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+Network Working Group                                          N. Haller
+Request for Comments: 1760                                      Bellcore
+Category: Informational                                    February 1995
+
+
+                   The S/KEY One-Time Password System
+
+Status of this Memo
+
+   This memo provides information for the Internet community.  This memo
+   does not specify an Internet standard of any kind.  Distribution of
+   this memo is unlimited.
+
+Abstract
+
+   This document describes the S/KEY* One-Time Password system as
+   released for public use by Bellcore and as described in reference
+   [3].  A reference implementation and documentation are available by
+   anonymous ftp from ftp.bellcore.com in the directories pub/nmh/...
+
+Overview
+
+   One form of attack on computing system connected to the Internet is
+   eavesdropping on network connections to obtain login id's and
+   passwords of legitimate users.  The captured login id and password
+   are, at a later time, used gain access to the system.  The S/KEY
+   One-Time Password system is designed to counter this type of attack,
+   called a replay attack.
+
+   With the S/KEY system, only a single use password ever crosses the
+   network.  The user's secret pass-phrase never crosses the network at
+   any time, including during login or when executing other commands
+   requiring authentication such as the UNIX commands passwd or su.
+   Thus, it is not vulnerable to eavesdropping/replay attacks.  Added
+   security is provided by the property that no secret information need
+   be stored on any system, including the host being protected.
+
+   The S/KEY system protects against external passive attacks against
+   the authentication subsystem.  It does not prevent a network
+   eavesdropper from gaining access to private information, and does not
+   provide protection against "inside jobs" or against active attacks
+   where the potential intruder as able to intercept and modify the
+   packet stream.
+
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+
+Haller                                                          [Page 1]
+
+RFC 1760           The S/KEY One-Time Password System      February 1995
+
+
+Introduction
+
+   There are two sides to the operation of the S/KEY one-time password
+   system.  On the client side, the appropriate one-time password must
+   be generated.  On the host side, the server must verify the one-time
+   password and permit the secure changing of the user's secret pass-
+   phrase.
+
+   An S/KEY system client passes the user's secret pass-phrase through
+   multiple applications of a secure hash function to produce a one-time
+   password.  On each use, the number of applications is reduced by one.
+   Thus a unique sequence of passwords is generated.  The S/KEY system
+   host verifies the one-time password by making one pass though the
+   secure hash function and comparing the result with the previous one-
+   time password.  This technique was first suggested by Leslie Lamport
+   [1].
+
+Secure Hash Function
+
+   A secure hash function is a function that is easy to compute in the
+   forward direction, but computationally infeasible to invert.  The
+   S/KEY system is based on the MD4 Message Digest algorithm designed by
+   Ronald Rivest [2].  Since the S/KEY authentication system went into
+   use, the MD5 Message Digest was released.  We have chosen to continue
+   to use MD4 due the large number of client programs that have been
+   distributed.  Some sites have generated functionally similar systems
+   based on MD5.  Clearly clients and hosts must use the same secure
+   hash function to interoperate.
+
+   The S/KEY system one-time passwords are 64 bits in length.  This is
+   believed to be long enough to be secure and short enough to be
+   manually entered (see below, Form of Passwords) when necessary.
+
+   The S/KEY system applies the secure hash function multiple times,
+   producing a 64 bit final output.  MD4 accepts an arbitrary number of
+   bits as input and produces a 128 bit output.  The S/KEY secure hash
+   function consists of applying MD4 to a 64 bit input and folding the
+   output of MD4 with exclusive or to produce a 64 bit output.
+
+Generation of One-Time Passwords
+
+   This section describes the computation of the S/KEY one-time
+   passwords.  It consists of a preparatory step in which all inputs are
+   combined, a generation step where the secure hash function is applied
+   multiple times, and an output function where the 64 bit one-time
+
+
+
+
+
+
+Haller                                                          [Page 2]
+
+RFC 1760           The S/KEY One-Time Password System      February 1995
+
+
+   password is displayed in readable form.
+
+   The client's secret pass phrase may be of any length and should be
+   more than eight characters.  As the S/KEY secure hash function
+   described above accepts a 64 bit input, a preparatory step is needed.
+   In this step, the pass phrase is concatenated with a seed that is
+   transmitted from the server in clear text.  This non-secret seed
+   allows a client to use the same secret pass phrase on multiple
+   machines (using different seeds) and to safely recycle secret
+   passwords by changing the seed.  (For ease in parsing, the seed may
+   not contain any blanks, and should consist of strictly alphanumeric
+   characters.) The result of the concatenation is passed through MD4,
+   and then reduced to 64 bits by exclusive-OR of the two 8-byte halves.
+
+   The following code fragment uses the MD4 implementation defined in
+   RFC 1320 [2] and defines the preparatory step:
+
+         strcpy(buf,seed);
+         strcat(buf,passwd);
+         MDbegin(&md)
+         MDupdate(&md,(unsigned char *)buf,8*buflen);
+
+         /* Fold result to 64 bits */
+         md.buffer[0] ^= md.buffer[2];
+         md.buffer[1] ^= md.buffer[3];
+
+   A sequence of one-time passwords is produced by applying the secure
+   hash function multiple times to the output of the preparatory step
+   (called S).  That is, the first one-time password is produced by
+   passing S through the secure hash function a number of times (N)
+   specified by the user.  The next one-time password is generated by
+   passing S though the secure hash function N-1 times.  An eavesdropper
+   who has monitored the transmission of a one-time password would not
+   be able to generate any succeeding password because doing so would
+   require inverting the hash function.
+
+Form of Passwords
+
+   The one-time password generated by the above procedure is 64 bits in
+   length.  Entering a 64 bit number is a difficult and error prone
+   process.  Some S/KEY system one-time password calculator programs
+   insert this password into the input stream, others make it available
+   for system cut and paste.  Some arrangements require the one-time
+   password to be entered manually. The S/KEY system is designed to
+   facilitate this manual entry without impeding automatic methods.  The
+   one-time password is therefore converted to, and accepted as, a
+   sequence of six short (1 to 4 letter) English words.  Each word is
+   chosen from a dictionary of 2048 words; at 11 bits per word, all
+
+
+
+Haller                                                          [Page 3]
+
+RFC 1760           The S/KEY One-Time Password System      February 1995
+
+
+   one-time passwords may be encoded.  Interoperability requires at all
+   S/KEY system hosts and calculators use the same dictionary.  The
+   standard dictionary is attached to this RFC.
+
+Verification of One-Time Passwords
+
+   A function on the host system that requires S/KEY authentication is
+   expected to issue an S/KEY challenge.  This challenge give the client
+   the current S/KEY parameters - the sequence number and seed.  It is
+   important that the S/KEY challenge be in a standard format so that
+   automated clients (see below) can recognize the challenge and extract
+   the parameters.  The format of the challenge is:
+
+        s/key sequence_integer seed
+
+   The three tokens are separated by single space characters.  The
+   challenge is terminated by a blank or a newline.
+
+   Given the parameters and the secret pass phrase, the client can
+   compute (or lookup) the one time password.  It then passes it to the
+   host system where it can be verified.
+
+   The host system has a file (on the UNIX reference implementation it
+   is /etc/skeykeys) containing, for each user, the one-time password
+   from the last successful login, or it may be initialized with the
+   first one-time password of the sequence using the keyinit command
+   (this command name may be implementation dependent).  To verify an
+   authentication attempt, it passes the transmitted one-time password
+   through the secure hash function one time.  If the result of this
+   operation matches the stored previous one-time password, the
+   authentication is successful and the accepted one-time password is
+   stored for future use.
+
+   Because the number of hash function applications executed by the
+   client decreases by one each time, at some point the user must
+   reinitialize the system of be unable to login again.  This is done by
+   using the keyinit command which allows the changing of the secret
+   pass phrase, the iteration count, and the seed. A frequent technique
+   is to increment a trailing digit(s) of the seed and to reset the
+   iteration count (to something in range of 500-1000).
+
+Clients
+
+   Several programs are available to calculate S/KEY one time passwords.
+   Included in the reference implementation are command line interfaces
+   for UNIX and PC systems (key), TSR interfaces for PCs (ctkey,
+   termkey, and popkey), and GUI interfaces for Macintosh and Windows
+   (keyapp and un-named Macintosh interface).
+
+
+
+Haller                                                          [Page 4]
+
+RFC 1760           The S/KEY One-Time Password System      February 1995
+
+
+   The most basic calculator is the key command whose format is:
+
+        key [-n count] sequence seed
+
+   The optional count is used to display more than a single one time
+   password.  This is useful to create a paper list of one time
+   passwords.
+
+   The most automated calculator is the termkey program that runs as a
+   Terminate and Stay Resident (TSR) program on a PC.  It scans the
+   screen to find the S/KEY parameters, prompts for the secret pass
+   phrase, and stuffs the one time password into the keyboard buffer.
+
+Acknowledgements
+
+   The idea behind S/KEY authentication was first proposed by Leslie
+   Lamport [1].  The specific system described was proposed by Phil
+   Karn, who also wrote most of the reference implementation.
+
+References
+
+   [1] Lamport, L., "Password Authentication with Insecure
+       Communication", Communications of the ACM 24.11, November 1981,
+       770-772.
+
+   [2] Rivest, R., "The MD4 Message-Digest Algorithm", RFC 1320, MIT and
+       RSA Data Security, Inc., April 1992
+
+   [3] Haller, N., "The S/KEY One-Time Password System", Proceedings of
+       the ISOC Symposium on Network and Distributed System Security,
+       February 1994, San Diego, CA
+
+   [4] Haller, N., and R. Atkinson, "On Internet Authentication", RFC
+       1704, Bell Communications Research and Naval Research Laboratory,
+       October 1994
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+Haller                                                          [Page 5]
+
+RFC 1760           The S/KEY One-Time Password System      February 1995
+
+
+Security Considerations
+
+   This entire document is about Security Considerations.
+
+Author's Address
+
+   Neil Haller
+   Bellcore
+   MRE 2Q-280
+   445 South Street
+   Morristown, NJ, 07960-6438, USA
+
+   Phone: +1 201 829-4478
+   Fax:  +1 201 829-2504
+   EMail: nmh@bellcore.com
+
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+Haller                                                          [Page 6]
+
+RFC 1760           The S/KEY One-Time Password System      February 1995
+
+
+Dictionary for Converting Between S/KEY 6-Word and Binary Formats
+
+   This dictionary is from the module put.c.  The code for this module,
+   and an implementation of the entire S/KEY One Time Password System is
+   available by anonymous ftp from ftp.bellcore.com in the directory
+   pub/nmh/skey.
+
+
+{        "A",     "ABE",   "ACE",   "ACT",   "AD",    "ADA",   "ADD",
+"AGO",   "AID",   "AIM",   "AIR",   "ALL",   "ALP",   "AM",    "AMY",
+"AN",    "ANA",   "AND",   "ANN",   "ANT",   "ANY",   "APE",   "APS",
+"APT",   "ARC",   "ARE",   "ARK",   "ARM",   "ART",   "AS",    "ASH",
+"ASK",   "AT",    "ATE",   "AUG",   "AUK",   "AVE",   "AWE",   "AWK",
+"AWL",   "AWN",   "AX",    "AYE",   "BAD",   "BAG",   "BAH",   "BAM",
+"BAN",   "BAR",   "BAT",   "BAY",   "BE",    "BED",   "BEE",   "BEG",
+"BEN",   "BET",   "BEY",   "BIB",   "BID",   "BIG",   "BIN",   "BIT",
+"BOB",   "BOG",   "BON",   "BOO",   "BOP",   "BOW",   "BOY",   "BUB",
+"BUD",   "BUG",   "BUM",   "BUN",   "BUS",   "BUT",   "BUY",   "BY",
+"BYE",   "CAB",   "CAL",   "CAM",   "CAN",   "CAP",   "CAR",   "CAT",
+"CAW",   "COD",   "COG",   "COL",   "CON",   "COO",   "COP",   "COT",
+"COW",   "COY",   "CRY",   "CUB",   "CUE",   "CUP",   "CUR",   "CUT",
+"DAB",   "DAD",   "DAM",   "DAN",   "DAR",   "DAY",   "DEE",   "DEL",
+"DEN",   "DES",   "DEW",   "DID",   "DIE",   "DIG",   "DIN",   "DIP",
+"DO",    "DOE",   "DOG",   "DON",   "DOT",   "DOW",   "DRY",   "DUB",
+"DUD",   "DUE",   "DUG",   "DUN",   "EAR",   "EAT",   "ED",    "EEL",
+"EGG",   "EGO",   "ELI",   "ELK",   "ELM",   "ELY",   "EM",    "END",
+"EST",   "ETC",   "EVA",   "EVE",   "EWE",   "EYE",   "FAD",   "FAN",
+"FAR",   "FAT",   "FAY",   "FED",   "FEE",   "FEW",   "FIB",   "FIG",
+"FIN",   "FIR",   "FIT",   "FLO",   "FLY",   "FOE",   "FOG",   "FOR",
+"FRY",   "FUM",   "FUN",   "FUR",   "GAB",   "GAD",   "GAG",   "GAL",
+"GAM",   "GAP",   "GAS",   "GAY",   "GEE",   "GEL",   "GEM",   "GET",
+"GIG",   "GIL",   "GIN",   "GO",    "GOT",   "GUM",   "GUN",   "GUS",
+"GUT",   "GUY",   "GYM",   "GYP",   "HA",    "HAD",   "HAL",   "HAM",
+"HAN",   "HAP",   "HAS",   "HAT",   "HAW",   "HAY",   "HE",    "HEM",
+"HEN",   "HER",   "HEW",   "HEY",   "HI",    "HID",   "HIM",   "HIP",
+"HIS",   "HIT",   "HO",    "HOB",   "HOC",   "HOE",   "HOG",   "HOP",
+"HOT",   "HOW",   "HUB",   "HUE",   "HUG",   "HUH",   "HUM",   "HUT",
+"I",     "ICY",   "IDA",   "IF",    "IKE",   "ILL",   "INK",   "INN",
+"IO",    "ION",   "IQ",    "IRA",   "IRE",   "IRK",   "IS",    "IT",
+"ITS",   "IVY",   "JAB",   "JAG",   "JAM",   "JAN",   "JAR",   "JAW",
+"JAY",   "JET",   "JIG",   "JIM",   "JO",    "JOB",   "JOE",   "JOG",
+"JOT",   "JOY",   "JUG",   "JUT",   "KAY",   "KEG",   "KEN",   "KEY",
+"KID",   "KIM",   "KIN",   "KIT",   "LA",    "LAB",   "LAC",   "LAD",
+"LAG",   "LAM",   "LAP",   "LAW",   "LAY",   "LEA",   "LED",   "LEE",
+"LEG",   "LEN",   "LEO",   "LET",   "LEW",   "LID",   "LIE",   "LIN",
+"LIP",   "LIT",   "LO",    "LOB",   "LOG",   "LOP",   "LOS",   "LOT",
+"LOU",   "LOW",   "LOY",   "LUG",   "LYE",   "MA",    "MAC",   "MAD",
+"MAE",   "MAN",   "MAO",   "MAP",   "MAT",   "MAW",   "MAY",   "ME",
+
+
+
+Haller                                                          [Page 7]
+
+RFC 1760           The S/KEY One-Time Password System      February 1995
+
+
+"MEG",   "MEL",   "MEN",   "MET",   "MEW",   "MID",   "MIN",   "MIT",
+"MOB",   "MOD",   "MOE",   "MOO",   "MOP",   "MOS",   "MOT",   "MOW",
+"MUD",   "MUG",   "MUM",   "MY",    "NAB",   "NAG",   "NAN",   "NAP",
+"NAT",   "NAY",   "NE",    "NED",   "NEE",   "NET",   "NEW",   "NIB",
+"NIL",   "NIP",   "NIT",   "NO",    "NOB",   "NOD",   "NON",   "NOR",
+"NOT",   "NOV",   "NOW",   "NU",    "NUN",   "NUT",   "O",     "OAF",
+"OAK",   "OAR",   "OAT",   "ODD",   "ODE",   "OF",    "OFF",   "OFT",
+"OH",    "OIL",   "OK",    "OLD",   "ON",    "ONE",   "OR",    "ORB",
+"ORE",   "ORR",   "OS",    "OTT",   "OUR",   "OUT",   "OVA",   "OW",
+"OWE",   "OWL",   "OWN",   "OX",    "PA",    "PAD",   "PAL",   "PAM",
+"PAN",   "PAP",   "PAR",   "PAT",   "PAW",   "PAY",   "PEA",   "PEG",
+"PEN",   "PEP",   "PER",   "PET",   "PEW",   "PHI",   "PI",    "PIE",
+"PIN",   "PIT",   "PLY",   "PO",    "POD",   "POE",   "POP",   "POT",
+"POW",   "PRO",   "PRY",   "PUB",   "PUG",   "PUN",   "PUP",   "PUT",
+"QUO",   "RAG",   "RAM",   "RAN",   "RAP",   "RAT",   "RAW",   "RAY",
+"REB",   "RED",   "REP",   "RET",   "RIB",   "RID",   "RIG",   "RIM",
+"RIO",   "RIP",   "ROB",   "ROD",   "ROE",   "RON",   "ROT",   "ROW",
+"ROY",   "RUB",   "RUE",   "RUG",   "RUM",   "RUN",   "RYE",   "SAC",
+"SAD",   "SAG",   "SAL",   "SAM",   "SAN",   "SAP",   "SAT",   "SAW",
+"SAY",   "SEA",   "SEC",   "SEE",   "SEN",   "SET",   "SEW",   "SHE",
+"SHY",   "SIN",   "SIP",   "SIR",   "SIS",   "SIT",   "SKI",   "SKY",
+"SLY",   "SO",    "SOB",   "SOD",   "SON",   "SOP",   "SOW",   "SOY",
+"SPA",   "SPY",   "SUB",   "SUD",   "SUE",   "SUM",   "SUN",   "SUP",
+"TAB",   "TAD",   "TAG",   "TAN",   "TAP",   "TAR",   "TEA",   "TED",
+"TEE",   "TEN",   "THE",   "THY",   "TIC",   "TIE",   "TIM",   "TIN",
+"TIP",   "TO",    "TOE",   "TOG",   "TOM",   "TON",   "TOO",   "TOP",
+"TOW",   "TOY",   "TRY",   "TUB",   "TUG",   "TUM",   "TUN",   "TWO",
+"UN",    "UP",    "US",    "USE",   "VAN",   "VAT",   "VET",   "VIE",
+"WAD",   "WAG",   "WAR",   "WAS",   "WAY",   "WE",    "WEB",   "WED",
+"WEE",   "WET",   "WHO",   "WHY",   "WIN",   "WIT",   "WOK",   "WON",
+"WOO",   "WOW",   "WRY",   "WU",    "YAM",   "YAP",   "YAW",   "YE",
+"YEA",   "YES",   "YET",   "YOU",   "ABED",  "ABEL",  "ABET",  "ABLE",
+"ABUT",  "ACHE",  "ACID",  "ACME",  "ACRE",  "ACTA",  "ACTS",  "ADAM",
+"ADDS",  "ADEN",  "AFAR",  "AFRO",  "AGEE",  "AHEM",  "AHOY",  "AIDA",
+"AIDE",  "AIDS",  "AIRY",  "AJAR",  "AKIN",  "ALAN",  "ALEC",  "ALGA",
+"ALIA",  "ALLY",  "ALMA",  "ALOE",  "ALSO",  "ALTO",  "ALUM",  "ALVA",
+"AMEN",  "AMES",  "AMID",  "AMMO",  "AMOK",  "AMOS",  "AMRA",  "ANDY",
+"ANEW",  "ANNA",  "ANNE",  "ANTE",  "ANTI",  "AQUA",  "ARAB",  "ARCH",
+"AREA",  "ARGO",  "ARID",  "ARMY",  "ARTS",  "ARTY",  "ASIA",  "ASKS",
+"ATOM",  "AUNT",  "AURA",  "AUTO",  "AVER",  "AVID",  "AVIS",  "AVON",
+"AVOW",  "AWAY",  "AWRY",  "BABE",  "BABY",  "BACH",  "BACK",  "BADE",
+"BAIL",  "BAIT",  "BAKE",  "BALD",  "BALE",  "BALI",  "BALK",  "BALL",
+"BALM",  "BAND",  "BANE",  "BANG",  "BANK",  "BARB",  "BARD",  "BARE",
+"BARK",  "BARN",  "BARR",  "BASE",  "BASH",  "BASK",  "BASS",  "BATE",
+"BATH",  "BAWD",  "BAWL",  "BEAD",  "BEAK",  "BEAM",  "BEAN",  "BEAR",
+"BEAT",  "BEAU",  "BECK",  "BEEF",  "BEEN",  "BEER",  "BEET",  "BELA",
+"BELL",  "BELT",  "BEND",  "BENT",  "BERG",  "BERN",  "BERT",  "BESS",
+"BEST",  "BETA",  "BETH",  "BHOY",  "BIAS",  "BIDE",  "BIEN",  "BILE",
+
+
+
+Haller                                                          [Page 8]
+
+RFC 1760           The S/KEY One-Time Password System      February 1995
+
+
+"BILK",  "BILL",  "BIND",  "BING",  "BIRD",  "BITE",  "BITS",  "BLAB",
+"BLAT",  "BLED",  "BLEW",  "BLOB",  "BLOC",  "BLOT",  "BLOW",  "BLUE",
+"BLUM",  "BLUR",  "BOAR",  "BOAT",  "BOCA",  "BOCK",  "BODE",  "BODY",
+"BOGY",  "BOHR",  "BOIL",  "BOLD",  "BOLO",  "BOLT",  "BOMB",  "BONA",
+"BOND",  "BONE",  "BONG",  "BONN",  "BONY",  "BOOK",  "BOOM",  "BOON",
+"BOOT",  "BORE",  "BORG",  "BORN",  "BOSE",  "BOSS",  "BOTH",  "BOUT",
+"BOWL",  "BOYD",  "BRAD",  "BRAE",  "BRAG",  "BRAN",  "BRAY",  "BRED",
+"BREW",  "BRIG",  "BRIM",  "BROW",  "BUCK",  "BUDD",  "BUFF",  "BULB",
+"BULK",  "BULL",  "BUNK",  "BUNT",  "BUOY",  "BURG",  "BURL",  "BURN",
+"BURR",  "BURT",  "BURY",  "BUSH",  "BUSS",  "BUST",  "BUSY",  "BYTE",
+"CADY",  "CAFE",  "CAGE",  "CAIN",  "CAKE",  "CALF",  "CALL",  "CALM",
+"CAME",  "CANE",  "CANT",  "CARD",  "CARE",  "CARL",  "CARR",  "CART",
+"CASE",  "CASH",  "CASK",  "CAST",  "CAVE",  "CEIL",  "CELL",  "CENT",
+"CERN",  "CHAD",  "CHAR",  "CHAT",  "CHAW",  "CHEF",  "CHEN",  "CHEW",
+"CHIC",  "CHIN",  "CHOU",  "CHOW",  "CHUB",  "CHUG",  "CHUM",  "CITE",
+"CITY",  "CLAD",  "CLAM",  "CLAN",  "CLAW",  "CLAY",  "CLOD",  "CLOG",
+"CLOT",  "CLUB",  "CLUE",  "COAL",  "COAT",  "COCA",  "COCK",  "COCO",
+"CODA",  "CODE",  "CODY",  "COED",  "COIL",  "COIN",  "COKE",  "COLA",
+"COLD",  "COLT",  "COMA",  "COMB",  "COME",  "COOK",  "COOL",  "COON",
+"COOT",  "CORD",  "CORE",  "CORK",  "CORN",  "COST",  "COVE",  "COWL",
+"CRAB",  "CRAG",  "CRAM",  "CRAY",  "CREW",  "CRIB",  "CROW",  "CRUD",
+"CUBA",  "CUBE",  "CUFF",  "CULL",  "CULT",  "CUNY",  "CURB",  "CURD",
+"CURE",  "CURL",  "CURT",  "CUTS",  "DADE",  "DALE",  "DAME",  "DANA",
+"DANE",  "DANG",  "DANK",  "DARE",  "DARK",  "DARN",  "DART",  "DASH",
+"DATA",  "DATE",  "DAVE",  "DAVY",  "DAWN",  "DAYS",  "DEAD",  "DEAF",
+"DEAL",  "DEAN",  "DEAR",  "DEBT",  "DECK",  "DEED",  "DEEM",  "DEER",
+"DEFT",  "DEFY",  "DELL",  "DENT",  "DENY",  "DESK",  "DIAL",  "DICE",
+"DIED",  "DIET",  "DIME",  "DINE",  "DING",  "DINT",  "DIRE",  "DIRT",
+"DISC",  "DISH",  "DISK",  "DIVE",  "DOCK",  "DOES",  "DOLE",  "DOLL",
+"DOLT",  "DOME",  "DONE",  "DOOM",  "DOOR",  "DORA",  "DOSE",  "DOTE",
+"DOUG",  "DOUR",  "DOVE",  "DOWN",  "DRAB",  "DRAG",  "DRAM",  "DRAW",
+"DREW",  "DRUB",  "DRUG",  "DRUM",  "DUAL",  "DUCK",  "DUCT",  "DUEL",
+"DUET",  "DUKE",  "DULL",  "DUMB",  "DUNE",  "DUNK",  "DUSK",  "DUST",
+"DUTY",  "EACH",  "EARL",  "EARN",  "EASE",  "EAST",  "EASY",  "EBEN",
+"ECHO",  "EDDY",  "EDEN",  "EDGE",  "EDGY",  "EDIT",  "EDNA",  "EGAN",
+"ELAN",  "ELBA",  "ELLA",  "ELSE",  "EMIL",  "EMIT",  "EMMA",  "ENDS",
+"ERIC",  "EROS",  "EVEN",  "EVER",  "EVIL",  "EYED",  "FACE",  "FACT",
+"FADE",  "FAIL",  "FAIN",  "FAIR",  "FAKE",  "FALL",  "FAME",  "FANG",
+"FARM",  "FAST",  "FATE",  "FAWN",  "FEAR",  "FEAT",  "FEED",  "FEEL",
+"FEET",  "FELL",  "FELT",  "FEND",  "FERN",  "FEST",  "FEUD",  "FIEF",
+"FIGS",  "FILE",  "FILL",  "FILM",  "FIND",  "FINE",  "FINK",  "FIRE",
+"FIRM",  "FISH",  "FISK",  "FIST",  "FITS",  "FIVE",  "FLAG",  "FLAK",
+"FLAM",  "FLAT",  "FLAW",  "FLEA",  "FLED",  "FLEW",  "FLIT",  "FLOC",
+"FLOG",  "FLOW",  "FLUB",  "FLUE",  "FOAL",  "FOAM",  "FOGY",  "FOIL",
+"FOLD",  "FOLK",  "FOND",  "FONT",  "FOOD",  "FOOL",  "FOOT",  "FORD",
+"FORE",  "FORK",  "FORM",  "FORT",  "FOSS",  "FOUL",  "FOUR",  "FOWL",
+"FRAU",  "FRAY",  "FRED",  "FREE",  "FRET",  "FREY",  "FROG",  "FROM",
+"FUEL",  "FULL",  "FUME",  "FUND",  "FUNK",  "FURY",  "FUSE",  "FUSS",
+
+
+
+Haller                                                          [Page 9]
+
+RFC 1760           The S/KEY One-Time Password System      February 1995
+
+
+"GAFF",  "GAGE",  "GAIL",  "GAIN",  "GAIT",  "GALA",  "GALE",  "GALL",
+"GALT",  "GAME",  "GANG",  "GARB",  "GARY",  "GASH",  "GATE",  "GAUL",
+"GAUR",  "GAVE",  "GAWK",  "GEAR",  "GELD",  "GENE",  "GENT",  "GERM",
+"GETS",  "GIBE",  "GIFT",  "GILD",  "GILL",  "GILT",  "GINA",  "GIRD",
+"GIRL",  "GIST",  "GIVE",  "GLAD",  "GLEE",  "GLEN",  "GLIB",  "GLOB",
+"GLOM",  "GLOW",  "GLUE",  "GLUM",  "GLUT",  "GOAD",  "GOAL",  "GOAT",
+"GOER",  "GOES",  "GOLD",  "GOLF",  "GONE",  "GONG",  "GOOD",  "GOOF",
+"GORE",  "GORY",  "GOSH",  "GOUT",  "GOWN",  "GRAB",  "GRAD",  "GRAY",
+"GREG",  "GREW",  "GREY",  "GRID",  "GRIM",  "GRIN",  "GRIT",  "GROW",
+"GRUB",  "GULF",  "GULL",  "GUNK",  "GURU",  "GUSH",  "GUST",  "GWEN",
+"GWYN",  "HAAG",  "HAAS",  "HACK",  "HAIL",  "HAIR",  "HALE",  "HALF",
+"HALL",  "HALO",  "HALT",  "HAND",  "HANG",  "HANK",  "HANS",  "HARD",
+"HARK",  "HARM",  "HART",  "HASH",  "HAST",  "HATE",  "HATH",  "HAUL",
+"HAVE",  "HAWK",  "HAYS",  "HEAD",  "HEAL",  "HEAR",  "HEAT",  "HEBE",
+"HECK",  "HEED",  "HEEL",  "HEFT",  "HELD",  "HELL",  "HELM",  "HERB",
+"HERD",  "HERE",  "HERO",  "HERS",  "HESS",  "HEWN",  "HICK",  "HIDE",
+"HIGH",  "HIKE",  "HILL",  "HILT",  "HIND",  "HINT",  "HIRE",  "HISS",
+"HIVE",  "HOBO",  "HOCK",  "HOFF",  "HOLD",  "HOLE",  "HOLM",  "HOLT",
+"HOME",  "HONE",  "HONK",  "HOOD",  "HOOF",  "HOOK",  "HOOT",  "HORN",
+"HOSE",  "HOST",  "HOUR",  "HOVE",  "HOWE",  "HOWL",  "HOYT",  "HUCK",
+"HUED",  "HUFF",  "HUGE",  "HUGH",  "HUGO",  "HULK",  "HULL",  "HUNK",
+"HUNT",  "HURD",  "HURL",  "HURT",  "HUSH",  "HYDE",  "HYMN",  "IBIS",
+"ICON",  "IDEA",  "IDLE",  "IFFY",  "INCA",  "INCH",  "INTO",  "IONS",
+"IOTA",  "IOWA",  "IRIS",  "IRMA",  "IRON",  "ISLE",  "ITCH",  "ITEM",
+"IVAN",  "JACK",  "JADE",  "JAIL",  "JAKE",  "JANE",  "JAVA",  "JEAN",
+"JEFF",  "JERK",  "JESS",  "JEST",  "JIBE",  "JILL",  "JILT",  "JIVE",
+"JOAN",  "JOBS",  "JOCK",  "JOEL",  "JOEY",  "JOHN",  "JOIN",  "JOKE",
+"JOLT",  "JOVE",  "JUDD",  "JUDE",  "JUDO",  "JUDY",  "JUJU",  "JUKE",
+"JULY",  "JUNE",  "JUNK",  "JUNO",  "JURY",  "JUST",  "JUTE",  "KAHN",
+"KALE",  "KANE",  "KANT",  "KARL",  "KATE",  "KEEL",  "KEEN",  "KENO",
+"KENT",  "KERN",  "KERR",  "KEYS",  "KICK",  "KILL",  "KIND",  "KING",
+"KIRK",  "KISS",  "KITE",  "KLAN",  "KNEE",  "KNEW",  "KNIT",  "KNOB",
+"KNOT",  "KNOW",  "KOCH",  "KONG",  "KUDO",  "KURD",  "KURT",  "KYLE",
+"LACE",  "LACK",  "LACY",  "LADY",  "LAID",  "LAIN",  "LAIR",  "LAKE",
+"LAMB",  "LAME",  "LAND",  "LANE",  "LANG",  "LARD",  "LARK",  "LASS",
+"LAST",  "LATE",  "LAUD",  "LAVA",  "LAWN",  "LAWS",  "LAYS",  "LEAD",
+"LEAF",  "LEAK",  "LEAN",  "LEAR",  "LEEK",  "LEER",  "LEFT",  "LEND",
+"LENS",  "LENT",  "LEON",  "LESK",  "LESS",  "LEST",  "LETS",  "LIAR",
+"LICE",  "LICK",  "LIED",  "LIEN",  "LIES",  "LIEU",  "LIFE",  "LIFT",
+"LIKE",  "LILA",  "LILT",  "LILY",  "LIMA",  "LIMB",  "LIME",  "LIND",
+"LINE",  "LINK",  "LINT",  "LION",  "LISA",  "LIST",  "LIVE",  "LOAD",
+"LOAF",  "LOAM",  "LOAN",  "LOCK",  "LOFT",  "LOGE",  "LOIS",  "LOLA",
+"LONE",  "LONG",  "LOOK",  "LOON",  "LOOT",  "LORD",  "LORE",  "LOSE",
+"LOSS",  "LOST",  "LOUD",  "LOVE",  "LOWE",  "LUCK",  "LUCY",  "LUGE",
+"LUKE",  "LULU",  "LUND",  "LUNG",  "LURA",  "LURE",  "LURK",  "LUSH",
+"LUST",  "LYLE",  "LYNN",  "LYON",  "LYRA",  "MACE",  "MADE",  "MAGI",
+"MAID",  "MAIL",  "MAIN",  "MAKE",  "MALE",  "MALI",  "MALL",  "MALT",
+"MANA",  "MANN",  "MANY",  "MARC",  "MARE",  "MARK",  "MARS",  "MART",
+
+
+
+Haller                                                         [Page 10]
+
+RFC 1760           The S/KEY One-Time Password System      February 1995
+
+
+"MARY",  "MASH",  "MASK",  "MASS",  "MAST",  "MATE",  "MATH",  "MAUL",
+"MAYO",  "MEAD",  "MEAL",  "MEAN",  "MEAT",  "MEEK",  "MEET",  "MELD",
+"MELT",  "MEMO",  "MEND",  "MENU",  "MERT",  "MESH",  "MESS",  "MICE",
+"MIKE",  "MILD",  "MILE",  "MILK",  "MILL",  "MILT",  "MIMI",  "MIND",
+"MINE",  "MINI",  "MINK",  "MINT",  "MIRE",  "MISS",  "MIST",  "MITE",
+"MITT",  "MOAN",  "MOAT",  "MOCK",  "MODE",  "MOLD",  "MOLE",  "MOLL",
+"MOLT",  "MONA",  "MONK",  "MONT",  "MOOD",  "MOON",  "MOOR",  "MOOT",
+"MORE",  "MORN",  "MORT",  "MOSS",  "MOST",  "MOTH",  "MOVE",  "MUCH",
+"MUCK",  "MUDD",  "MUFF",  "MULE",  "MULL",  "MURK",  "MUSH",  "MUST",
+"MUTE",  "MUTT",  "MYRA",  "MYTH",  "NAGY",  "NAIL",  "NAIR",  "NAME",
+"NARY",  "NASH",  "NAVE",  "NAVY",  "NEAL",  "NEAR",  "NEAT",  "NECK",
+"NEED",  "NEIL",  "NELL",  "NEON",  "NERO",  "NESS",  "NEST",  "NEWS",
+"NEWT",  "NIBS",  "NICE",  "NICK",  "NILE",  "NINA",  "NINE",  "NOAH",
+"NODE",  "NOEL",  "NOLL",  "NONE",  "NOOK",  "NOON",  "NORM",  "NOSE",
+"NOTE",  "NOUN",  "NOVA",  "NUDE",  "NULL",  "NUMB",  "OATH",  "OBEY",
+"OBOE",  "ODIN",  "OHIO",  "OILY",  "OINT",  "OKAY",  "OLAF",  "OLDY",
+"OLGA",  "OLIN",  "OMAN",  "OMEN",  "OMIT",  "ONCE",  "ONES",  "ONLY",
+"ONTO",  "ONUS",  "ORAL",  "ORGY",  "OSLO",  "OTIS",  "OTTO",  "OUCH",
+"OUST",  "OUTS",  "OVAL",  "OVEN",  "OVER",  "OWLY",  "OWNS",  "QUAD",
+"QUIT",  "QUOD",  "RACE",  "RACK",  "RACY",  "RAFT",  "RAGE",  "RAID",
+"RAIL",  "RAIN",  "RAKE",  "RANK",  "RANT",  "RARE",  "RASH",  "RATE",
+"RAVE",  "RAYS",  "READ",  "REAL",  "REAM",  "REAR",  "RECK",  "REED",
+"REEF",  "REEK",  "REEL",  "REID",  "REIN",  "RENA",  "REND",  "RENT",
+"REST",  "RICE",  "RICH",  "RICK",  "RIDE",  "RIFT",  "RILL",  "RIME",
+"RING",  "RINK",  "RISE",  "RISK",  "RITE",  "ROAD",  "ROAM",  "ROAR",
+"ROBE",  "ROCK",  "RODE",  "ROIL",  "ROLL",  "ROME",  "ROOD",  "ROOF",
+"ROOK",  "ROOM",  "ROOT",  "ROSA",  "ROSE",  "ROSS",  "ROSY",  "ROTH",
+"ROUT",  "ROVE",  "ROWE",  "ROWS",  "RUBE",  "RUBY",  "RUDE",  "RUDY",
+"RUIN",  "RULE",  "RUNG",  "RUNS",  "RUNT",  "RUSE",  "RUSH",  "RUSK",
+"RUSS",  "RUST",  "RUTH",  "SACK",  "SAFE",  "SAGE",  "SAID",  "SAIL",
+"SALE",  "SALK",  "SALT",  "SAME",  "SAND",  "SANE",  "SANG",  "SANK",
+"SARA",  "SAUL",  "SAVE",  "SAYS",  "SCAN",  "SCAR",  "SCAT",  "SCOT",
+"SEAL",  "SEAM",  "SEAR",  "SEAT",  "SEED",  "SEEK",  "SEEM",  "SEEN",
+"SEES",  "SELF",  "SELL",  "SEND",  "SENT",  "SETS",  "SEWN",  "SHAG",
+"SHAM",  "SHAW",  "SHAY",  "SHED",  "SHIM",  "SHIN",  "SHOD",  "SHOE",
+"SHOT",  "SHOW",  "SHUN",  "SHUT",  "SICK",  "SIDE",  "SIFT",  "SIGH",
+"SIGN",  "SILK",  "SILL",  "SILO",  "SILT",  "SINE",  "SING",  "SINK",
+"SIRE",  "SITE",  "SITS",  "SITU",  "SKAT",  "SKEW",  "SKID",  "SKIM",
+"SKIN",  "SKIT",  "SLAB",  "SLAM",  "SLAT",  "SLAY",  "SLED",  "SLEW",
+"SLID",  "SLIM",  "SLIT",  "SLOB",  "SLOG",  "SLOT",  "SLOW",  "SLUG",
+"SLUM",  "SLUR",  "SMOG",  "SMUG",  "SNAG",  "SNOB",  "SNOW",  "SNUB",
+"SNUG",  "SOAK",  "SOAR",  "SOCK",  "SODA",  "SOFA",  "SOFT",  "SOIL",
+"SOLD",  "SOME",  "SONG",  "SOON",  "SOOT",  "SORE",  "SORT",  "SOUL",
+"SOUR",  "SOWN",  "STAB",  "STAG",  "STAN",  "STAR",  "STAY",  "STEM",
+"STEW",  "STIR",  "STOW",  "STUB",  "STUN",  "SUCH",  "SUDS",  "SUIT",
+"SULK",  "SUMS",  "SUNG",  "SUNK",  "SURE",  "SURF",  "SWAB",  "SWAG",
+"SWAM",  "SWAN",  "SWAT",  "SWAY",  "SWIM",  "SWUM",  "TACK",  "TACT",
+"TAIL",  "TAKE",  "TALE",  "TALK",  "TALL",  "TANK",  "TASK",  "TATE",
+
+
+
+Haller                                                         [Page 11]
+
+RFC 1760           The S/KEY One-Time Password System      February 1995
+
+
+"TAUT",  "TEAL",  "TEAM",  "TEAR",  "TECH",  "TEEM",  "TEEN",  "TEET",
+"TELL",  "TEND",  "TENT",  "TERM",  "TERN",  "TESS",  "TEST",  "THAN",
+"THAT",  "THEE",  "THEM",  "THEN",  "THEY",  "THIN",  "THIS",  "THUD",
+"THUG",  "TICK",  "TIDE",  "TIDY",  "TIED",  "TIER",  "TILE",  "TILL",
+"TILT",  "TIME",  "TINA",  "TINE",  "TINT",  "TINY",  "TIRE",  "TOAD",
+"TOGO",  "TOIL",  "TOLD",  "TOLL",  "TONE",  "TONG",  "TONY",  "TOOK",
+"TOOL",  "TOOT",  "TORE",  "TORN",  "TOTE",  "TOUR",  "TOUT",  "TOWN",
+"TRAG",  "TRAM",  "TRAY",  "TREE",  "TREK",  "TRIG",  "TRIM",  "TRIO",
+"TROD",  "TROT",  "TROY",  "TRUE",  "TUBA",  "TUBE",  "TUCK",  "TUFT",
+"TUNA",  "TUNE",  "TUNG",  "TURF",  "TURN",  "TUSK",  "TWIG",  "TWIN",
+"TWIT",  "ULAN",  "UNIT",  "URGE",  "USED",  "USER",  "USES",  "UTAH",
+"VAIL",  "VAIN",  "VALE",  "VARY",  "VASE",  "VAST",  "VEAL",  "VEDA",
+"VEIL",  "VEIN",  "VEND",  "VENT",  "VERB",  "VERY",  "VETO",  "VICE",
+"VIEW",  "VINE",  "VISE",  "VOID",  "VOLT",  "VOTE",  "WACK",  "WADE",
+"WAGE",  "WAIL",  "WAIT",  "WAKE",  "WALE",  "WALK",  "WALL",  "WALT",
+"WAND",  "WANE",  "WANG",  "WANT",  "WARD",  "WARM",  "WARN",  "WART",
+"WASH",  "WAST",  "WATS",  "WATT",  "WAVE",  "WAVY",  "WAYS",  "WEAK",
+"WEAL",  "WEAN",  "WEAR",  "WEED",  "WEEK",  "WEIR",  "WELD",  "WELL",
+"WELT",  "WENT",  "WERE",  "WERT",  "WEST",  "WHAM",  "WHAT",  "WHEE",
+"WHEN",  "WHET",  "WHOA",  "WHOM",  "WICK",  "WIFE",  "WILD",  "WILL",
+"WIND",  "WINE",  "WING",  "WINK",  "WINO",  "WIRE",  "WISE",  "WISH",
+"WITH",  "WOLF",  "WONT",  "WOOD",  "WOOL",  "WORD",  "WORE",  "WORK",
+"WORM",  "WORN",  "WOVE",  "WRIT",  "WYNN",  "YALE",  "YANG",  "YANK",
+"YARD",  "YARN",  "YAWL",  "YAWN",  "YEAH",  "YEAR",  "YELL",  "YOGA",
+"YOKE"   };
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Haller                                                         [Page 12]
+
diff --git a/docs/rfc2289.txt b/docs/rfc2289.txt
new file mode 100644
index 0000000..8d1d722
--- /dev/null
+++ b/docs/rfc2289.txt
@@ -0,0 +1,1403 @@
+
+
+
+
+
+
+Network Working Group                                        N. Haller
+Request for Comments: 2289                                    Bellcore
+Obsoletes: 1938                                                C. Metz
+Category: Standards Track                   Kaman Sciences Corporation
+                                                             P. Nesser
+                                            Nesser & Nesser Consulting
+                                                              M. Straw
+                                                              Bellcore
+                                                         February 1998
+
+
+                       A One-Time Password System
+
+Status of this Memo
+
+   This document specifies an Internet standards track protocol for the
+   Internet community, and requests discussion and suggestions for
+   improvements.  Please refer to the current edition of the "Internet
+   Official Protocol Standards" (STD 1) for the standardization state
+   and status of this protocol.  Distribution of this memo is unlimited.
+
+Copyright Notice
+
+   Copyright (C) The Internet Society (1998).  All Rights Reserved.
+
+1.0 ABSTRACT
+
+   This document describes a one-time password authentication system
+   (OTP). The system provides authentication for system access (login)
+   and other applications requiring authentication that is secure
+   against passive attacks based on replaying captured reusable
+   passwords. OTP evolved from the S/KEY (S/KEY is a trademark of
+   Bellcore) One-Time Password System that was released by Bellcore and
+   is described in references [3] and [5].
+
+2.0 OVERVIEW
+
+   One form of attack on networked computing systems is eavesdropping on
+   network connections to obtain authentication information such as the
+   login IDs and passwords of legitimate users. Once this information is
+   captured, it can be used at a later time to gain access to the
+   system. One-time password systems are designed to counter this type
+   of attack, called a "replay attack" [4].
+
+   The authentication system described in this document uses a secret
+   pass-phrase to generate a sequence of one-time (single use)
+   passwords.  With this system, the user's secret pass-phrase never
+   needs to cross the network at any time such as during authentication
+
+
+
+Haller                      Standards Track                     [Page 1]
+
+RFC 2289               A One-Time Password System          February 1998
+
+
+   or during pass-phrase changes. Thus, it is not vulnerable to replay
+   attacks.  Added security is provided by the property that no secret
+   information need be stored on any system, including the server being
+   protected.
+
+   The OTP system protects against external passive attacks against the
+   authentication subsystem. It does not prevent a network eavesdropper
+   from gaining access to private information and does not provide
+   protection against either "social engineering" or active attacks [9].
+
+3.0 INTRODUCTION
+
+   There are two entities in the operation of the OTP one-time password
+   system. The generator must produce the appropriate one-time password
+   from the user's secret pass-phrase and from information provided in
+   the challenge from the server. The server must send a challenge that
+   includes the appropriate generation parameters to the generator, must
+   verify the one-time password received, must store the last valid
+   one-time password it received, and must store the corresponding one-
+   time password sequence number. The server must also facilitate the
+   changing of the user's secret pass-phrase in a secure manner.
+
+   The OTP system generator passes the user's secret pass-phrase, along
+   with a seed received from the server as part of the challenge,
+   through multiple iterations of a secure hash function to produce a
+   one-time password. After each successful authentication, the number
+   of secure hash function iterations is reduced by one.  Thus, a unique
+   sequence of passwords is generated.  The server verifies the one-time
+   password received from the generator by computing the secure hash
+   function once and comparing the result with the previously accepted
+   one-time password.  This technique was first suggested by Leslie
+   Lamport [1].
+
+4.0 REQUIREMENTS TERMINOLOGY
+
+   In this document, the words that are used to define the significance
+   of each particular requirement are usually capitalized.  These words
+   are:
+
+     - MUST
+
+       This word or the adjective "REQUIRED" means that the item is an
+       absolute requirement of the specification.
+
+
+
+
+
+
+
+
+Haller                      Standards Track                     [Page 2]
+
+RFC 2289               A One-Time Password System          February 1998
+
+
+     - SHOULD
+
+       This word or the adjective "RECOMMENDED" means that there might
+       exist valid reasons in particular circumstances to ignore this
+       item, but the full implications should be understood and the case
+       carefully weighed before taking a different course.
+
+     - MAY
+
+       This word or the adjective "OPTIONAL" means that this item is
+       truly optional.  One vendor might choose to include the item
+       because a particular marketplace requires it or because it
+       enhances the product, for example; another vendor may omit the
+       same item.
+
+5.0 SECURE HASH FUNCTION
+
+   The security of the OTP system is based on the non-invertability of a
+   secure hash function. Such a function must be tractable to compute in
+   the forward direction, but computationally infeasible to invert.
+
+   The interfaces are currently defined for three such hash algorithms,
+   MD4 [2] and MD5 [6] by Ronald Rivest, and SHA [7] by NIST.  All
+   conforming implementations of both server and generators MUST support
+   MD5.  They SHOULD support SHA and MAY also support MD4.  Clearly, the
+   generator and server must use the same algorithm in order to
+   interoperate. Other hash algorithms may be specified for use with
+   this system by publishing the appropriate interfaces.
+
+   The secure hash algorithms listed above have the property that they
+   accept an input that is arbitrarily long and produce a fixed size
+   output. The OTP system folds this output to 64 bits using the
+   algorithms in the Appendix A. 64 bits is also the length of the one-
+   time passwords. This is believed to be long enough to be secure and
+   short enough to be entered manually (see below, Form of Output) when
+   necessary.
+
+6.0 GENERATION OF ONE-TIME PASSWORDS
+
+   This section describes the generation of the one-time passwords.
+   This process consists of an initial step in which all inputs are
+   combined, a computation step where the secure hash function is
+   applied a specified number of times, and an output function where the
+   64 bit one-time password is converted to a human readable form.
+
+   Appendix C contains examples of the outputs given a collection of
+   inputs.  It provides implementors with a means of verification the
+   use of these algorithms.
+
+
+
+Haller                      Standards Track                     [Page 3]
+
+RFC 2289               A One-Time Password System          February 1998
+
+
+   Initial Step
+
+   In principle, the user's secret pass-phrase may be of any length. To
+   reduce the risk from techniques such as exhaustive search or
+   dictionary attacks, character string pass-phrases MUST contain at
+   least 10 characters (see Form of Inputs below).  All implementations
+   MUST support a pass-phrases of at least 63 characters.  The secret
+   pass-phrase is frequently, but is not required to be, textual
+   information provided by a user.
+
+   In this step, the pass phrase is concatenated with a seed that is
+   transmitted from the server in clear text. This non-secret seed
+   allows clients to use the same secret pass-phrase on multiple
+   machines (using different seeds) and to safely recycle their secret
+   pass-phrases by changing the seed.
+
+   The result of the concatenation is passed through the secure hash
+   function and then is reduced to 64 bits using one of the function
+   dependent algorithms shown in Appendix A.
+
+   Computation Step
+
+   A sequence of one-time passwords is produced by applying the secure
+   hash function multiple times to the output of the initial step
+   (called S). That is, the first one-time password to be used is
+   produced by passing S through the secure hash function a number of
+   times (N) specified by the user. The next one-time password to be
+   used is generated by passing S though the secure hash function N-1
+   times. An eavesdropper who has monitored the transmission of a one-
+   time password would not be able to generate the next required
+   password because doing so would mean inverting the hash function.
+
+   Form of Inputs
+
+   The secret pass-phrase is seen only by the OTP generator. To allow
+   interchangeability of generators, all generators MUST support a
+   secret pass-phrase of 10 to 63 characters. Implementations MAY
+   support a longer pass-phrase, but such implementations risk the loss
+   of interchangeability with implementations supporting only the
+   minimum.
+
+   The seed MUST consist of purely alphanumeric characters and MUST be
+   of one to 16 characters in length. The seed is a string of characters
+   that MUST not contain any blanks and SHOULD consist of strictly
+   alphanumeric characters from the ISO-646 Invariant Code Set.  The
+   seed MUST be case insensitive and MUST be internally converted to
+   lower case before it is processed.
+
+
+
+
+Haller                      Standards Track                     [Page 4]
+
+RFC 2289               A One-Time Password System          February 1998
+
+
+   The sequence number and seed together constitute a larger unit of
+   data called the challenge. The challenge gives the generator the
+   parameters it needs to calculate the correct one-time password from
+   the secret pass-phrase. The challenge MUST be in a standard syntax so
+   that automated generators can recognize the challenge in context and
+   extract these parameters. The syntax of the challenge is:
+
+           otp-<algorithm identifier> <sequence integer> <seed>
+
+   The three tokens MUST be separated by a white space (defined as any
+   number of spaces and/or tabs) and the entire challenge string MUST be
+   terminated with either a space or a new line. The string "otp-" MUST
+   be in lower case.  The algorithm identifier is case sensitive (the
+   existing identifiers are all lower case), and the seed is case
+   insensitive and converted before use to lower case.  If additional
+   algorithms are defined, appropriate identifiers (short, but not
+   limited to three or four characters) must be defined. The currently
+   defined algorithm identifiers are:
+
+       md4        MD4 Message Digest
+       md5        MD5 Message Digest
+       sha1       NIST Secure Hash Algorithm Revision 1
+
+   An example of an OTP challenge is:   otp-md5 487 dog2
+
+   Form of Output
+
+   The one-time password generated by the above procedure is 64 bits in
+   length. Entering a 64 bit number is a difficult and error prone
+   process. Some generators insert this password into the input stream
+   and some others make it available for system "cut and paste." Still
+   other arrangements require the one-time password to be entered
+   manually. The OTP system is designed to facilitate this manual entry
+   without impeding automatic methods. The one-time password therefore
+   MAY be converted to, and all servers MUST be capable of accepting it
+   as, a sequence of six short (1 to 4 letter) easily typed words that
+   only use characters from ISO-646 IVCS. Each word is chosen from a
+   dictionary of 2048 words; at 11 bits per word, all one-time passwords
+   may be encoded.
+
+   The two extra bits in this encoding are used to store a checksum.
+   The 64 bits of key are broken down into pairs of bits, then these
+   pairs are summed together. The two least significant bits of this sum
+   are encoded in the last two bits of the six word sequence with the
+   least significant bit of the sum as the last bit encoded. All OTP
+   generators MUST calculate this checksum and all OTP servers MUST
+   verify this checksum explicitly as part of the operation of decoding
+   this representation of the one-time password.
+
+
+
+Haller                      Standards Track                     [Page 5]
+
+RFC 2289               A One-Time Password System          February 1998
+
+
+   Generators that produce the six-word format MUST present the words in
+   upper case with single spaces used as separators. All servers MUST
+   accept six-word format without regard to case and white space used as
+   a separator. The two lines below represent the same one-time
+   password.  The first is valid as output from a generator and as input
+   a server, the second is valid only as human input to a server.
+
+            OUST COAT FOAL MUG BEAK TOTE
+            oust coat foal  mug  beak  tote
+
+     Interoperability requires that all OTP servers and generators use
+     the same dictionary. The standard dictionary was originally
+     specified in the "S/KEY One Time Password System" that is described
+     in RFC 1760 [5].  This dictionary is included in this document as
+     Appendix D.
+
+     To facilitate the implementation of smaller generators, hexadecimal
+     output is an acceptable alternative for the presentation of the
+     one-time password. All implementations of the server software MUST
+     accept case-insensitive hexadecimal as well as six-word format. The
+     hexadecimal digits may be separated by white space so servers are
+     REQUIRED to ignore all white space.  If the representation is
+     partitioned by white space, leading zeros must be retained.
+     Examples of hexadecimal format are:
+
+           Representation                Value
+
+           3503785b369cda8b              0x3503785b369cda8b
+           e5cc a1b8 7c13 096b           0xe5cca1b87c13096b
+           C7 48 90 F4 27 7B A1 CF       0xc74890f4277ba1cf
+           47 9 A68 28 4C 9D 0 1BC       0x479a68284c9d01bc
+
+   In addition to accepting six-word and hexadecimal encodings of the
+   64 bit one-time password, servers SHOULD accept the alternate
+   dictionary encoding described in Appendix B.  The six words in this
+   encoding MUST not overlap the set of words in the standard
+   dictionary.  To avoid ambiguity with the hexadecimal representation,
+   words in the alternate dictionary MUST not be comprised solely of
+   the letters A-F.  Decoding words thus encoded does not require any
+   knowledge of the alternative dictionary used so the acceptance of
+   any alternate dictionary implies the acceptance of all alternate
+   dictionaries.  Words in the alternative dictionaries are case
+   sensitive.  Generators and servers MUST preserve the case in the
+   processing of these words.
+
+   In summary, all conforming servers MUST accept six-word input that
+   uses the Standard Dictionary (RFC 1760 and Appendix D), MUST accept
+   hexadecimal encoding, and SHOULD accept six-word input that uses the
+
+
+
+Haller                      Standards Track                     [Page 6]
+
+RFC 2289               A One-Time Password System          February 1998
+
+
+   Alternative Dictionary technique (Appendix B).  As there is a remote
+   possibility that a hexadecimal encoding of a one-time password will
+   look like a valid six-word standard dictionary encoding, all
+   implementations MUST use the following scheme.  If a six-word
+   encoded one-time password is valid, it is accepted.  Otherwise, if
+   the one-time password can be interpreted as hexadecimal, and with
+   that decoding it is valid, then it is accepted.
+
+7.0 VERIFICATION OF ONE-TIME PASSWORDS
+
+   An application on the server system that requires OTP authentication
+   is expected to issue an OTP challenge as described above. Given the
+   parameters from this challenge and the secret pass-phrase, the
+   generator can compute (or lookup) the one-time password that is
+   passed to the server to be verified.
+
+   The server system has a database containing, for each user, the
+   one-time password from the last successful authentication or the
+   first OTP of a newly initialized sequence. To authenticate the user,
+   the server decodes the one-time password received from the generator
+   into a 64-bit key and then runs this key through the secure hash
+   function once. If the result of this operation matches the stored
+   previous OTP, the authentication is successful and the accepted
+   one-time password is stored for future use.
+
+8.0 PASS-PHRASE CHANGES
+
+   Because the number of hash function applications executed by the
+   generator decreases by one each time, at some point the user must
+   reinitialize the system or be unable to authenticate.
+
+   Although some installations may not permit users to initialize
+   remotely, implementations MUST provide a means to do so that does
+   not reveal the user's secret pass-phrase.  One way is to provide a
+   means to reinitialize the  sequence through explicit specification
+   of the first one-time password.
+
+   When the sequence of one-time passwords is reinitialized,
+   implementations MUST verify that the seed or the pass-phrase is
+   changed.  Installations SHOULD discourage any operation that sends
+   the secret pass-phrase over a network in clear-text as such practice
+   defeats the concept of a one-time password.
+
+   Implementations MAY use the following technique for
+   [re]initialization:
+
+
+
+
+
+
+Haller                      Standards Track                     [Page 7]
+
+RFC 2289               A One-Time Password System          February 1998
+
+
+      o  The user picks a new seed and hash count (default values may
+         be offered).  The user provides these, along with the
+         corresponding generated one-time password, to the host system.
+
+      o  The user MAY also provide the corresponding generated one
+         time password for count-1 as an error check.
+
+      o  The user SHOULD provide the generated one-time password for
+         the old seed and old hash count to protect an idle terminal
+         or workstation (this implies that when the count is 1, the
+         user can login but cannot then change the seed or count).
+
+   In the future a specific protocol may be defined for
+   reinitialization that will permit smooth and possibly automated
+   interoperation of all hosts and generators.
+
+9.0 PROTECTION AGAINST RACE ATTACK
+
+   All conforming server implementations MUST protect against the race
+   condition described in this section.  A defense against this attack
+   is outlined; implementations MAY use this approach or MAY select an
+   alternative defense.
+
+   It is possible for an attacker to listen to most of a one-time
+   password, guess the remainder, and then race the legitimate user to
+   complete the authentication.  Multiple guesses against the last word
+   of the six-word format are likely to succeed.
+
+   One possible defense is to prevent a user from starting multiple
+   simultaneous authentication sessions. This means that once the
+   legitimate user has initiated authentication, an attacker would be
+   blocked until the first authentication process has completed.  In
+   this approach, a timeout is necessary to thwart a denial of service
+   attack.
+
+10.0 SECURITY CONSIDERATIONS
+
+   This entire document discusses an authentication system that
+   improves security by limiting the danger of eavesdropping/replay
+   attacks that have been used against simple password systems [4].
+
+   The use of the OTP system only provides protections against passive
+   eavesdropping/replay attacks.  It does not provide for the privacy
+   of transmitted data, and it does not provide protection against
+   active attacks such as session hijacking that are known to be
+   present in the current Internet [9].  The use of IP Security
+   (IPsec), see [10], [11], and [12] is recommended to protect against
+   TCP session hijacking.
+
+
+
+Haller                      Standards Track                     [Page 8]
+
+RFC 2289               A One-Time Password System          February 1998
+
+
+   The success of the OTP system to protect host systems is dependent
+   on the non-invertability of the secure hash functions used.  To our
+   knowledge, none of the hash algorithms have been broken, but it is
+   generally believed [6] that MD4 is not as strong as MD5.  If a
+   server supports multiple hash algorithms, it is only as secure as
+   the weakest algorithm.
+
+11.0 ACKNOWLEDGMENTS
+
+   The idea behind OTP authentication was first proposed by Leslie
+   Lamport [1]. Bellcore's S/KEY system, from which OTP is derived, was
+   proposed by Phil Karn, who also wrote most of the Bellcore reference
+   implementation.
+
+12.0 REFERENCES
+
+   [1]  Leslie Lamport, "Password Authentication with Insecure
+        Communication", Communications of the ACM 24.11 (November
+        1981), 770-772
+
+   [2]  Rivest, R., "The MD4 Message-Digest Algorithm", RFC 1320,
+        April 1992.
+
+   [3]  Neil Haller, "The S/KEY One-Time Password System", Proceedings
+        of the ISOC Symposium on Network and Distributed System
+        Security, February 1994, San Diego, CA
+
+   [4]  Haller, N., and R. Atkinson, "On Internet Authentication",
+        RFC 1704, October 1994.
+
+   [5]  Haller, N., "The S/KEY One-Time Password System",
+        RFC 1760, February 1995.
+
+   [6]  Rivest, R., "The MD5 Message-Digest Algorithm", RFC 1321,
+        April 1992.
+
+   [7]  National Institute of Standards and Technology (NIST),
+        "Announcing the Secure Hash Standard", FIPS 180-1, U.S.
+        Department of Commerce, April 1995.
+
+   [8]  International Standard - Information Processing -- ISO 7-bit
+        coded character set for information interchange (Invariant Code
+        Set), ISO-646, International Standards Organization, Geneva,
+        Switzerland, 1983
+
+
+
+
+
+
+
+Haller                      Standards Track                     [Page 9]
+
+RFC 2289               A One-Time Password System          February 1998
+
+
+   [9]  Computer Emergency Response Team (CERT), "IP Spoofing and
+        Hijacked Terminal Connections", CA-95:01, January 1995.
+        Available via anonymous ftp from info.cert.org in
+        /pub/cert_advisories.
+
+   [10] Atkinson, R., "Security Architecture for the Internet Protocol",
+        RFC 1825, August 1995.
+
+   [11] Atkinson, R., "IP Authentication Header", RFC 1826, August
+        1995.
+
+   [12] Atkinson, R., "IP Encapsulating Security Payload (ESP)", RFC
+        1827, August 1995.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Haller                      Standards Track                    [Page 10]
+
+RFC 2289               A One-Time Password System          February 1998
+
+
+13.0 AUTHORS' ADDRESSES
+
+   Neil Haller
+   Bellcore
+   MCC 1C-265B
+   445 South Street
+   Morristown, NJ, 07960-6438, USA
+
+   Phone: +1 201 829-4478
+   Fax:   +1 201 829-2504
+   EMail: nmh@bellcore.com
+
+
+   Craig Metz
+   Kaman Sciences Corporation
+   For NRL Code 5544
+   4555 Overlook Avenue, S.W.
+   Washington, DC, 20375-5337, USA
+
+   Phone: +1 202 404-7122
+   Fax:   +1 202 404-7942
+   EMail: cmetz@cs.nrl.navy.mil
+
+
+   Philip J. Nesser II
+   Nesser & Nesser Consulting
+   13501 100th Ave NE
+   Suite 5202
+   Kirkland, WA 98034, USA
+
+   Phone: +1 206 481 4303
+   EMail: pjnesser@martigny.ai.mit.edu
+
+
+   Mike Straw
+   Bellcore
+   RRC 1A-225
+   445 Hoes Lane
+   Piscataway, NJ 08854-4182
+
+   Phone:  +1 908 699-5212
+   EMail:  mess@bellcore.com
+
+
+
+
+
+
+
+
+
+Haller                      Standards Track                    [Page 11]
+
+RFC 2289               A One-Time Password System          February 1998
+
+
+Appendix A  -  Interfaces to Secure Hash Algorithms
+
+   Original interoperability tests provided valuable insights into the
+   subtle problems which occur when converting protocol specifications
+   into running code.  In particular, the manipulation of bit ordered
+   data is dependent on the architecture of the hardware, specifically
+   the way in which a computer stores multi-byte data.  The method is
+   typically called big or little "endian."  A big endian machine stores
+   data with the most significant byte first, while a little endian
+   machine stores the least significant byte first.  Thus, on a big
+   endian machine data is stored left to right, while little endian
+   machines store data right to left.
+
+   For example, the four byte value 0x11AABBCC is stored in a big endian
+   machine as the following series of four bytes, "0x11", "0xAA",
+   "0xBB", and "0xCC", while on a little endian machine the value would
+   be stored as "0xCC", "0xBB", "0xAA", and "0x11".
+
+   For historical reasons, and to promote interoperability with existing
+   implementations, it was decided that ALL hashes incorporated into the
+   OTP protocol MUST store the output of their hash function in LITTLE
+   ENDIAN format BEFORE the bit folding to 64 bits occurs.  This is done
+   in the implementations of MD4 and MD5 (see references [2] and [6]),
+   while it must be explicitly done for the implementation of SHA1 (see
+   reference [7]).
+
+   Any future hash functions implemented into the OTP protocol SHOULD
+   provide a similar reference fragment of code to allow independent
+   implementations to operate successfully.
+
+
+   MD4 Message Digest (see reference [2])
+
+     MD4_CTX md;
+     unsigned char result[16];
+
+     strcpy(buf, seed);     /* seed must be in lower case */
+     strcat(buf, passwd);
+     MD4Init(&md);
+     MD4Update(&md, (unsigned char *)buf, strlen(buf));
+     MD4Final(result, &md);
+
+     /* Fold the 128 bit result to 64 bits */
+     for (i = 0; i < 8; i++)
+             result[i] ^= result[i+8];
+
+
+
+
+
+
+Haller                      Standards Track                    [Page 12]
+
+RFC 2289               A One-Time Password System          February 1998
+
+
+MD5 Message Digest (see reference [6])
+
+     MD5_CTX md;
+     unsigned char result[16];
+     strcpy(buf, seed);     /* seed must be in lower case */
+     strcat(buf, passwd);
+     MD5Init(&md);
+     MD5Update(&md, (unsigned char *)buf, strlen(buf));
+     MD5Final(result, &md);
+
+     /* Fold the 128 bit result to 64 bits */
+     for (i = 0; i < 8; i++)
+             result[i] ^= result[i+8];
+
+
+SHA Secure Hash Algorithm (see reference [7])
+
+     SHA_INFO sha;
+     unsigned char result[16];
+     strcpy(buf, seed);     /* seed must be in lower case */
+     strcat(buf, passwd);
+     sha_init(&sha);
+     sha_update(&sha, (unsigned char *)buf, strlen(buf));
+     sha_final(&sha);       /* NOTE:  no result buffer */
+
+     /* Fold the 160 bit result to 64 bits */
+     sha.digest[0] ^= sha.digest[2];
+     sha.digest[1] ^= sha.digest[3];
+     sha.digest[0] ^= sha.digest[4];
+
+     /*
+      * copy the resulting 64 bits to the result buffer in little endian
+      * fashion (analogous to the way MD4Final() and MD5Final() do).
+      */
+     for (i = 0, j = 0; j < 8; i++, j += 4)
+     {
+             result[j]   = (unsigned char)(sha.digest[i] & 0xff);
+             result[j+1] = (unsigned char)((sha.digest[i] >> 8) & 0xff);
+             result[j+2] = (unsigned char)((sha.digest[i] >> 16) & 0xff);
+             result[j+3] = (unsigned char)((sha.digest[i] >> 24) & 0xff);
+     }
+
+
+
+
+
+
+
+
+
+
+Haller                      Standards Track                    [Page 13]
+
+RFC 2289               A One-Time Password System          February 1998
+
+
+Appendix B   -   Alternative Dictionary Algorithm
+
+   The purpose of alternative dictionary encoding of the OTP one-time
+   password is to allow the use of language specific or friendly words.
+   As case translation is not always well defined, the alternative
+   dictionary encoding is case sensitive.  Servers SHOULD accept this
+   encoding in addition to the standard 6-word and hexadecimal
+   encodings.
+
+
+   GENERATOR ENCODING USING AN ALTERNATE DICTIONARY
+
+     The standard 6-word encoding uses the placement of a word in the
+     dictionary to represent an 11-bit number. The 64-bit one-time
+     password can then be represented by six words.
+
+     An alternative dictionary of 2048 words may be created such that
+     each word W and position of the word in the dictionary N obey the
+     relationship:
+
+             alg( W ) % 2048 == N
+     where
+             alg is the hash algorithm used (e.g. MD4, MD5, SHA1).
+
+     In addition, no words in the standard dictionary may be chosen.
+
+     The generator expands the 64-bit one-time password to 66 bits by
+     computing parity as with the standard 6-word encoding.  The six 11-
+     bit numbers are then converted to words using the dictionary that
+     was created such that the above relationship holds.
+
+   SERVER DECODING OF ALTERNATE DICTIONARY ONE-TIME PASSWORDS
+
+     The server accepting alternative dictionary encoding converts each
+     word to an 11-bit number using the above encoding. These numbers
+     are then used in the same way as the decoded standard dictionary
+     words to form the 66-bit one-time password.
+
+     The server does not need to have access to the alternate dictionary
+     that was used to create the one-time password it is authenticating.
+     This is because the decoding from word to 11-bit number does not
+     make any use of the dictionary.  As a result of the independence of
+     the dictionary, a server accepting one alternate dictionary accept
+     all alternate dictionaries.
+
+
+
+
+
+
+
+Haller                      Standards Track                    [Page 14]
+
+RFC 2289               A One-Time Password System          February 1998
+
+
+Appendix C  -  OTP Verification Examples
+
+   This appendix provides a series of inputs and correct outputs for all
+   three of the defined OTP cryptographic hashes, specifically MD4, MD5,
+   and SHA1.  This document is intended to be used by developers for
+   interoperability checks when creating generators or servers.  Output
+   is provided in both hexadecimal notation and the six word encoding
+   documented in Appendix D.
+
+   GENERAL CHECKS
+
+   Note that the output given for these checks is not intended to be
+   taken literally, but describes the type of action that should be
+   taken.
+
+   Pass Phrase Length
+
+ Input:
+   Pass Phrase: Too_short
+   Seed: iamvalid
+   Count: 99
+   Hash: ANY
+ Output:
+   ERROR:  Pass Phrase too short
+
+ Input:
+   Pass Phrase:
+     1234567890123456789012345678901234567890123456789012345678901234
+   Seed: iamvalid
+   Count: 99
+   Hash: ANY
+ Output:
+   WARNING: Pass Phrase longer than the recommended maximum length of
+63
+
+Seed Values
+
+ Input:
+   Pass Phrase:  A_Valid_Pass_Phrase
+   Seed: Length_Okay
+   Count: 99
+   Hash: ANY
+ Output:
+   ERROR: Seed must be purely alphanumeric
+
+ Input:
+   Pass Phrase:  A_Valid_Pass_Phrase
+   Seed: LengthOfSeventeen
+
+
+
+Haller                      Standards Track                    [Page 15]
+
+RFC 2289               A One-Time Password System          February 1998
+
+
+   Count: 99
+   Hash: ANY
+
+ Output:
+   ERROR: Seed must be between 1 and 16 characters in length
+
+ Input:
+   Pass Phrase:  A_Valid_Pass_Phrase
+   Seed: A Seed
+   Count: 99
+   Hash: ANY
+ Output:
+   ERROR: Seed must not contain any spaces
+
+Parity Calculations
+
+ Input:
+   Pass Phrase: A_Valid_Pass_Phrase
+   Seed: AValidSeed
+   Count: 99
+   Hash: MD5
+ Output:
+   Hex: 85c43ee03857765b
+   Six Word(CORRECT):          FOWL KID MASH DEAD DUAL OAF
+   Six Word(INCORRECT PARITY): FOWL KID MASH DEAD DUAL NUT
+   Six Word(INCORRECT PARITY): FOWL KID MASH DEAD DUAL O
+   Six Word(INCORRECT PARITY): FOWL KID MASH DEAD DUAL OAK
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Haller                      Standards Track                    [Page 16]
+
+RFC 2289               A One-Time Password System          February 1998
+
+
+MD4 ENCODINGS
+
+Pass Phrase     Seed    Cnt Hex                 Six Word Format
+========================================================================
+This is a test. TeSt     0  D185 4218 EBBB 0B51
+                                           ROME MUG FRED SCAN LIVE LACE
+This is a test. TeSt     1  6347 3EF0 1CD0 B444
+                                           CARD SAD MINI RYE COL KIN
+This is a test. TeSt    99  C5E6 1277 6E6C 237A
+                                           NOTE OUT IBIS SINK NAVE MODE
+AbCdEfGhIjK     alpha1   0  5007 6F47 EB1A DE4E
+                                           AWAY SEN ROOK SALT LICE MAP
+AbCdEfGhIjK     alpha1   1  65D2 0D19 49B5 F7AB
+                                           CHEW GRIM WU HANG BUCK SAID
+AbCdEfGhIjK     alpha1  99  D150 C82C CE6F 62D1
+                                           ROIL FREE COG HUNK WAIT COCA
+OTP's are good  correct  0  849C 79D4 F6F5 5388
+                                           FOOL STEM DONE TOOL BECK NILE
+OTP's are good  correct  1  8C09 92FB 2508 47B1
+                                           GIST AMOS MOOT AIDS FOOD SEEM
+OTP's are good  correct 99  3F3B F4B4 145F D74B
+                                           TAG SLOW NOV MIN WOOL KENO
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Haller                      Standards Track                    [Page 17]
+
+RFC 2289               A One-Time Password System          February 1998
+
+
+MD5 ENCODINGS
+
+Pass Phrase     Seed    Cnt Hex                 Six Word Format
+========================================================================
+This is a test. TeSt     0  9E87 6134 D904 99DD
+                                           INCH SEA ANNE LONG AHEM TOUR
+This is a test. TeSt     1  7965 E054 36F5 029F
+                                           EASE OIL FUM CURE AWRY AVIS
+This is a test. TeSt    99  50FE 1962 C496 5880
+                                           BAIL TUFT BITS GANG CHEF THY
+AbCdEfGhIjK     alpha1   0  8706 6DD9 644B F206
+                                           FULL PEW DOWN ONCE MORT ARC
+AbCdEfGhIjK     alpha1   1  7CD3 4C10 40AD D14B
+                                           FACT HOOF AT FIST SITE KENT
+AbCdEfGhIjK     alpha1  99  5AA3 7A81 F212 146C
+                                           BODE HOP JAKE STOW JUT RAP
+OTP's are good  correct  0  F205 7539 43DE 4CF9
+                                           ULAN NEW ARMY FUSE SUIT EYED
+OTP's are good  correct  1  DDCD AC95 6F23 4937
+                                           SKIM CULT LOB SLAM POE HOWL
+OTP's are good  correct 99  B203 E28F A525 BE47
+                                           LONG IVY JULY AJAR BOND LEE
+
+
+SHA1 ENCODINGS
+
+Pass Phrase     Seed    Cnt Hex                 Six Word Format
+========================================================================
+This is a test. TeSt     0  BB9E 6AE1 979D 8FF4
+                                           MILT VARY MAST OK SEES WENT
+This is a test. TeSt     1  63D9 3663 9734 385B
+                                           CART OTTO HIVE ODE VAT NUT
+This is a test. TeSt    99  87FE C776 8B73 CCF9
+                                           GAFF WAIT SKID GIG SKY EYED
+AbCdEfGhIjK     alpha1   0  AD85 F658 EBE3 83C9
+                                           LEST OR HEEL SCOT ROB SUIT
+AbCdEfGhIjK     alpha1   1  D07C E229 B5CF 119B
+                                           RITE TAKE GELD COST TUNE RECK
+AbCdEfGhIjK     alpha1  99  27BC 7103 5AAF 3DC6
+                                           MAY STAR TIN LYON VEDA STAN
+OTP's are good  correct  0  D51F 3E99 BF8E 6F0B
+                                           RUST WELT KICK FELL TAIL FRAU
+OTP's are good  correct  1  82AE B52D 9437 74E4
+                                           FLIT DOSE ALSO MEW DRUM DEFY
+OTP's are good  correct 99  4F29 6A74 FE15 67EC
+                                           AURA ALOE HURL WING BERG WAIT
+
+
+
+
+
+Haller                      Standards Track                    [Page 18]
+
+RFC 2289               A One-Time Password System          February 1998
+
+
+Appendix D   -   Dictionary for Converting Between 6-Word and Binary Formats
+
+   This dictionary is from the module put.c in the original Bellcore
+   reference distribution.
+
+{        "A",     "ABE",   "ACE",   "ACT",   "AD",    "ADA",   "ADD",
+"AGO",   "AID",   "AIM",   "AIR",   "ALL",   "ALP",   "AM",    "AMY",
+"AN",    "ANA",   "AND",   "ANN",   "ANT",   "ANY",   "APE",   "APS",
+"APT",   "ARC",   "ARE",   "ARK",   "ARM",   "ART",   "AS",    "ASH",
+"ASK",   "AT",    "ATE",   "AUG",   "AUK",   "AVE",   "AWE",   "AWK",
+"AWL",   "AWN",   "AX",   "AYE",   "BAD",   "BAG",   "BAH",   "BAM",
+"BAN",   "BAR",   "BAT",   "BAY",   "BE",    "BED",   "BEE",   "BEG",
+"BEN",   "BET",   "BEY",   "BIB",   "BID",   "BIG",   "BIN",   "BIT",
+"BOB",   "BOG",   "BON",   "BOO",   "BOP",   "BOW",   "BOY",   "BUB",
+"BUD",   "BUG",   "BUM",   "BUN",   "BUS",   "BUT",   "BUY",   "BY",
+"BYE",   "CAB",   "CAL",   "CAM",   "CAN",   "CAP",   "CAR",   "CAT",
+"CAW",   "COD",   "COG",   "COL",   "CON",   "COO",   "COP",   "COT",
+"COW",   "COY",   "CRY",   "CUB",   "CUE",   "CUP",   "CUR",   "CUT",
+"DAB",   "DAD",   "DAM",   "DAN",   "DAR",   "DAY",   "DEE",   "DEL",
+"DEN",   "DES",   "DEW",   "DID",   "DIE",   "DIG",   "DIN",   "DIP",
+"DO",    "DOE",   "DOG",   "DON",   "DOT",   "DOW",   "DRY",   "DUB",
+"DUD",   "DUE",   "DUG",   "DUN",   "EAR",   "EAT",   "ED",    "EEL",
+"EGG",   "EGO",   "ELI",   "ELK",   "ELM",   "ELY",   "EM",    "END",
+"EST",   "ETC",   "EVA",   "EVE",   "EWE",   "EYE",   "FAD",   "FAN",
+"FAR",   "FAT",   "FAY",   "FED",   "FEE",   "FEW",   "FIB",   "FIG",
+"FIN",   "FIR",   "FIT",   "FLO",   "FLY",   "FOE",   "FOG",   "FOR",
+"FRY",   "FUM",   "FUN",   "FUR",   "GAB",   "GAD",   "GAG",   "GAL",
+"GAM",   "GAP",   "GAS",   "GAY",   "GEE",   "GEL",   "GEM",   "GET",
+"GIG",   "GIL",   "GIN",   "GO",    "GOT",   "GUM",   "GUN",   "GUS",
+"GUT",   "GUY",   "GYM",   "GYP",   "HA",    "HAD",   "HAL",   "HAM",
+"HAN",   "HAP",   "HAS",   "HAT",   "HAW",   "HAY",   "HE",    "HEM",
+"HEN",   "HER",   "HEW",   "HEY",   "HI",    "HID",   "HIM",   "HIP",
+"HIS",   "HIT",   "HO",   "HOB",   "HOC",   "HOE",   "HOG",   "HOP",
+"HOT",   "HOW",   "HUB",   "HUE",   "HUG",   "HUH",   "HUM",   "HUT",
+"I",     "ICY",   "IDA",   "IF",    "IKE",   "ILL",   "INK",   "INN",
+"IO",    "ION",   "IQ",   "IRA",   "IRE",   "IRK",   "IS",    "IT",
+"ITS",   "IVY",   "JAB",   "JAG",   "JAM",   "JAN",   "JAR",   "JAW",
+"JAY",   "JET",   "JIG",   "JIM",   "JO",    "JOB",   "JOE",   "JOG",
+"JOT",   "JOY",   "JUG",   "JUT",   "KAY",   "KEG",   "KEN",   "KEY",
+"KID",   "KIM",   "KIN",   "KIT",   "LA",    "LAB",   "LAC",   "LAD",
+"LAG",   "LAM",   "LAP",   "LAW",   "LAY",   "LEA",   "LED",   "LEE",
+"LEG",   "LEN",   "LEO",   "LET",   "LEW",   "LID",   "LIE",   "LIN",
+"LIP",   "LIT",   "LO",   "LOB",   "LOG",   "LOP",   "LOS",   "LOT",
+"LOU",   "LOW",   "LOY",   "LUG",   "LYE",   "MA",    "MAC",   "MAD",
+"MAE",   "MAN",   "MAO",   "MAP",   "MAT",   "MAW",   "MAY",   "ME",
+"MEG",   "MEL",   "MEN",   "MET",   "MEW",   "MID",   "MIN",   "MIT",
+"MOB",   "MOD",   "MOE",   "MOO",   "MOP",   "MOS",   "MOT",   "MOW",
+"MUD",   "MUG",   "MUM",   "MY",    "NAB",   "NAG",   "NAN",   "NAP",
+
+
+
+Haller                      Standards Track                    [Page 19]
+
+RFC 2289               A One-Time Password System          February 1998
+
+
+"NAT",   "NAY",   "NE",   "NED",   "NEE",   "NET",   "NEW",   "NIB",
+"NIL",   "NIP",   "NIT",   "NO",    "NOB",   "NOD",   "NON",   "NOR",
+"NOT",   "NOV",   "NOW",   "NU",    "NUN",   "NUT",   "O",     "OAF",
+"OAK",   "OAR",   "OAT",   "ODD",   "ODE",   "OF",    "OFF",   "OFT",
+"OH",    "OIL",   "OK",   "OLD",   "ON",    "ONE",   "OR",    "ORB",
+"ORE",   "ORR",   "OS",   "OTT",   "OUR",   "OUT",   "OVA",   "OW",
+"OWE",   "OWL",   "OWN",   "OX",    "PA",    "PAD",   "PAL",   "PAM",
+"PAN",   "PAP",   "PAR",   "PAT",   "PAW",   "PAY",   "PEA",   "PEG",
+"PEN",   "PEP",   "PER",   "PET",   "PEW",   "PHI",   "PI",    "PIE",
+"PIN",   "PIT",   "PLY",   "PO",    "POD",   "POE",   "POP",   "POT",
+"POW",   "PRO",   "PRY",   "PUB",   "PUG",   "PUN",   "PUP",   "PUT",
+"QUO",   "RAG",   "RAM",   "RAN",   "RAP",   "RAT",   "RAW",   "RAY",
+"REB",   "RED",   "REP",   "RET",   "RIB",   "RID",   "RIG",   "RIM",
+"RIO",   "RIP",   "ROB",   "ROD",   "ROE",   "RON",   "ROT",   "ROW",
+"ROY",   "RUB",   "RUE",   "RUG",   "RUM",   "RUN",   "RYE",   "SAC",
+"SAD",   "SAG",   "SAL",   "SAM",   "SAN",   "SAP",   "SAT",   "SAW",
+"SAY",   "SEA",   "SEC",   "SEE",   "SEN",   "SET",   "SEW",   "SHE",
+"SHY",   "SIN",   "SIP",   "SIR",   "SIS",   "SIT",   "SKI",   "SKY",
+"SLY",   "SO",    "SOB",   "SOD",   "SON",   "SOP",   "SOW",   "SOY",
+"SPA",   "SPY",   "SUB",   "SUD",   "SUE",   "SUM",   "SUN",   "SUP",
+"TAB",   "TAD",   "TAG",   "TAN",   "TAP",   "TAR",   "TEA",   "TED",
+"TEE",   "TEN",   "THE",   "THY",   "TIC",   "TIE",   "TIM",   "TIN",
+"TIP",   "TO",    "TOE",   "TOG",   "TOM",   "TON",   "TOO",   "TOP",
+"TOW",   "TOY",   "TRY",   "TUB",   "TUG",   "TUM",   "TUN",   "TWO",
+"UN",    "UP",    "US",   "USE",   "VAN",   "VAT",   "VET",   "VIE",
+"WAD",   "WAG",   "WAR",   "WAS",   "WAY",   "WE",    "WEB",   "WED",
+"WEE",   "WET",   "WHO",   "WHY",   "WIN",   "WIT",   "WOK",   "WON",
+"WOO",   "WOW",   "WRY",   "WU",    "YAM",   "YAP",   "YAW",   "YE",
+"YEA",   "YES",   "YET",   "YOU",   "ABED",  "ABEL",  "ABET",  "ABLE",
+"ABUT",  "ACHE",  "ACID",  "ACME",  "ACRE",  "ACTA",  "ACTS",  "ADAM",
+"ADDS",  "ADEN",  "AFAR",  "AFRO",  "AGEE",  "AHEM",  "AHOY",  "AIDA",
+"AIDE",  "AIDS",  "AIRY",  "AJAR",  "AKIN",  "ALAN",  "ALEC",  "ALGA",
+"ALIA",  "ALLY",  "ALMA",  "ALOE",  "ALSO",  "ALTO",  "ALUM",  "ALVA",
+"AMEN",  "AMES",  "AMID",  "AMMO",  "AMOK",  "AMOS",  "AMRA",  "ANDY",
+"ANEW",  "ANNA",  "ANNE",  "ANTE",  "ANTI",  "AQUA",  "ARAB",  "ARCH",
+"AREA",  "ARGO",  "ARID",  "ARMY",  "ARTS",  "ARTY",  "ASIA",  "ASKS",
+"ATOM",  "AUNT",  "AURA",  "AUTO",  "AVER",  "AVID",  "AVIS",  "AVON",
+"AVOW",  "AWAY",  "AWRY",  "BABE",  "BABY",  "BACH",  "BACK",  "BADE",
+"BAIL",  "BAIT",  "BAKE",  "BALD",  "BALE",  "BALI",  "BALK",  "BALL",
+"BALM",  "BAND",  "BANE",  "BANG",  "BANK",  "BARB",  "BARD",  "BARE",
+"BARK",  "BARN",  "BARR",  "BASE",  "BASH",  "BASK",  "BASS",  "BATE",
+"BATH",  "BAWD",  "BAWL",  "BEAD",  "BEAK",  "BEAM",  "BEAN",  "BEAR",
+"BEAT",  "BEAU",  "BECK",  "BEEF",  "BEEN",  "BEER",  "BEET",  "BELA",
+"BELL",  "BELT",  "BEND",  "BENT",  "BERG",  "BERN",  "BERT",  "BESS",
+"BEST",  "BETA",  "BETH",  "BHOY",  "BIAS",  "BIDE",  "BIEN",  "BILE",
+"BILK",  "BILL",  "BIND",  "BING",  "BIRD",  "BITE",  "BITS",  "BLAB",
+"BLAT",  "BLED",  "BLEW",  "BLOB",  "BLOC",  "BLOT",  "BLOW",  "BLUE",
+"BLUM",  "BLUR",  "BOAR",  "BOAT",  "BOCA",  "BOCK",  "BODE",  "BODY",
+
+
+
+Haller                      Standards Track                    [Page 20]
+
+RFC 2289               A One-Time Password System          February 1998
+
+
+"BOGY",  "BOHR",  "BOIL",  "BOLD",  "BOLO",  "BOLT",  "BOMB",  "BONA",
+"BOND",  "BONE",  "BONG",  "BONN",  "BONY",  "BOOK",  "BOOM",  "BOON",
+"BOOT",  "BORE",  "BORG",  "BORN",  "BOSE",  "BOSS",  "BOTH",  "BOUT",
+"BOWL",  "BOYD",  "BRAD",  "BRAE",  "BRAG",  "BRAN",  "BRAY",  "BRED",
+"BREW",  "BRIG",  "BRIM",  "BROW",  "BUCK",  "BUDD",  "BUFF",  "BULB",
+"BULK",  "BULL",  "BUNK",  "BUNT",  "BUOY",  "BURG",  "BURL",  "BURN",
+"BURR",  "BURT",  "BURY",  "BUSH",  "BUSS",  "BUST",  "BUSY",  "BYTE",
+"CADY",  "CAFE",  "CAGE",  "CAIN",  "CAKE",  "CALF",  "CALL",  "CALM",
+"CAME",  "CANE",  "CANT",  "CARD",  "CARE",  "CARL",  "CARR",  "CART",
+"CASE",  "CASH",  "CASK",  "CAST",  "CAVE",  "CEIL",  "CELL",  "CENT",
+"CERN",  "CHAD",  "CHAR",  "CHAT",  "CHAW",  "CHEF",  "CHEN",  "CHEW",
+"CHIC",  "CHIN",  "CHOU",  "CHOW",  "CHUB",  "CHUG",  "CHUM",  "CITE",
+"CITY",  "CLAD",  "CLAM",  "CLAN",  "CLAW",  "CLAY",  "CLOD",  "CLOG",
+"CLOT",  "CLUB",  "CLUE",  "COAL",  "COAT",  "COCA",  "COCK",  "COCO",
+"CODA",  "CODE",  "CODY",  "COED",  "COIL",  "COIN",  "COKE",  "COLA",
+"COLD",  "COLT",  "COMA",  "COMB",  "COME",  "COOK",  "COOL",  "COON",
+"COOT",  "CORD",  "CORE",  "CORK",  "CORN",  "COST",  "COVE",  "COWL",
+"CRAB",  "CRAG",  "CRAM",  "CRAY",  "CREW",  "CRIB",  "CROW",  "CRUD",
+"CUBA",  "CUBE",  "CUFF",  "CULL",  "CULT",  "CUNY",  "CURB",  "CURD",
+"CURE",  "CURL",  "CURT",  "CUTS",  "DADE",  "DALE",  "DAME",  "DANA",
+"DANE",  "DANG",  "DANK",  "DARE",  "DARK",  "DARN",  "DART",  "DASH",
+"DATA",  "DATE",  "DAVE",  "DAVY",  "DAWN",  "DAYS",  "DEAD",  "DEAF",
+"DEAL",  "DEAN",  "DEAR",  "DEBT",  "DECK",  "DEED",  "DEEM",  "DEER",
+"DEFT",  "DEFY",  "DELL",  "DENT",  "DENY",  "DESK",  "DIAL",  "DICE",
+"DIED",  "DIET",  "DIME",  "DINE",  "DING",  "DINT",  "DIRE",  "DIRT",
+"DISC",  "DISH",  "DISK",  "DIVE",  "DOCK",  "DOES",  "DOLE",  "DOLL",
+"DOLT",  "DOME",  "DONE",  "DOOM",  "DOOR",  "DORA",  "DOSE",  "DOTE",
+"DOUG",  "DOUR",  "DOVE",  "DOWN",  "DRAB",  "DRAG",  "DRAM",  "DRAW",
+"DREW",  "DRUB",  "DRUG",  "DRUM",  "DUAL",  "DUCK",  "DUCT",  "DUEL",
+"DUET",  "DUKE",  "DULL",  "DUMB",  "DUNE",  "DUNK",  "DUSK",  "DUST",
+"DUTY",  "EACH",  "EARL",  "EARN",  "EASE",  "EAST",  "EASY",  "EBEN",
+"ECHO",  "EDDY",  "EDEN",  "EDGE",  "EDGY",  "EDIT",  "EDNA",  "EGAN",
+"ELAN",  "ELBA",  "ELLA",  "ELSE",  "EMIL",  "EMIT",  "EMMA",  "ENDS",
+"ERIC",  "EROS",  "EVEN",  "EVER",  "EVIL",  "EYED",  "FACE",  "FACT",
+"FADE",  "FAIL",  "FAIN",  "FAIR",  "FAKE",  "FALL",  "FAME",  "FANG",
+"FARM",  "FAST",  "FATE",  "FAWN",  "FEAR",  "FEAT",  "FEED",  "FEEL",
+"FEET",  "FELL",  "FELT",  "FEND",  "FERN",  "FEST",  "FEUD",  "FIEF",
+"FIGS",  "FILE",  "FILL",  "FILM",  "FIND",  "FINE",  "FINK",  "FIRE",
+"FIRM",  "FISH",  "FISK",  "FIST",  "FITS",  "FIVE",  "FLAG",  "FLAK",
+"FLAM",  "FLAT",  "FLAW",  "FLEA",  "FLED",  "FLEW",  "FLIT",  "FLOC",
+"FLOG",  "FLOW",  "FLUB",  "FLUE",  "FOAL",  "FOAM",  "FOGY",  "FOIL",
+"FOLD",  "FOLK",  "FOND",  "FONT",  "FOOD",  "FOOL",  "FOOT",  "FORD",
+"FORE",  "FORK",  "FORM",  "FORT",  "FOSS",  "FOUL",  "FOUR",  "FOWL",
+"FRAU",  "FRAY",  "FRED",  "FREE",  "FRET",  "FREY",  "FROG",  "FROM",
+"FUEL",  "FULL",  "FUME",  "FUND",  "FUNK",  "FURY",  "FUSE",  "FUSS",
+"GAFF",  "GAGE",  "GAIL",  "GAIN",  "GAIT",  "GALA",  "GALE",  "GALL",
+"GALT",  "GAME",  "GANG",  "GARB",  "GARY",  "GASH",  "GATE",  "GAUL",
+"GAUR",  "GAVE",  "GAWK",  "GEAR",  "GELD",  "GENE",  "GENT",  "GERM",
+
+
+
+Haller                      Standards Track                    [Page 21]
+
+RFC 2289               A One-Time Password System          February 1998
+
+
+"GETS",  "GIBE",  "GIFT",  "GILD",  "GILL",  "GILT",  "GINA",  "GIRD",
+"GIRL",  "GIST",  "GIVE",  "GLAD",  "GLEE",  "GLEN",  "GLIB",  "GLOB",
+"GLOM",  "GLOW",  "GLUE",  "GLUM",  "GLUT",  "GOAD",  "GOAL",  "GOAT",
+"GOER",  "GOES",  "GOLD",  "GOLF",  "GONE",  "GONG",  "GOOD",  "GOOF",
+"GORE",  "GORY",  "GOSH",  "GOUT",  "GOWN",  "GRAB",  "GRAD",  "GRAY",
+"GREG",  "GREW",  "GREY",  "GRID",  "GRIM",  "GRIN",  "GRIT",  "GROW",
+"GRUB",  "GULF",  "GULL",  "GUNK",  "GURU",  "GUSH",  "GUST",  "GWEN",
+"GWYN",  "HAAG",  "HAAS",  "HACK",  "HAIL",  "HAIR",  "HALE",  "HALF",
+"HALL",  "HALO",  "HALT",  "HAND",  "HANG",  "HANK",  "HANS",  "HARD",
+"HARK",  "HARM",  "HART",  "HASH",  "HAST",  "HATE",  "HATH",  "HAUL",
+"HAVE",  "HAWK",  "HAYS",  "HEAD",  "HEAL",  "HEAR",  "HEAT",  "HEBE",
+"HECK",  "HEED",  "HEEL",  "HEFT",  "HELD",  "HELL",  "HELM",  "HERB",
+"HERD",  "HERE",  "HERO",  "HERS",  "HESS",  "HEWN",  "HICK",  "HIDE",
+"HIGH",  "HIKE",  "HILL",  "HILT",  "HIND",  "HINT",  "HIRE",  "HISS",
+"HIVE",  "HOBO",  "HOCK",  "HOFF",  "HOLD",  "HOLE",  "HOLM",  "HOLT",
+"HOME",  "HONE",  "HONK",  "HOOD",  "HOOF",  "HOOK",  "HOOT",  "HORN",
+"HOSE",  "HOST",  "HOUR",  "HOVE",  "HOWE",  "HOWL",  "HOYT",  "HUCK",
+"HUED",  "HUFF",  "HUGE",  "HUGH",  "HUGO",  "HULK",  "HULL",  "HUNK",
+"HUNT",  "HURD",  "HURL",  "HURT",  "HUSH",  "HYDE",  "HYMN",  "IBIS",
+"ICON",  "IDEA",  "IDLE",  "IFFY",  "INCA",  "INCH",  "INTO",  "IONS",
+"IOTA",  "IOWA",  "IRIS",  "IRMA",  "IRON",  "ISLE",  "ITCH",  "ITEM",
+"IVAN",  "JACK",  "JADE",  "JAIL",  "JAKE",  "JANE",  "JAVA",  "JEAN",
+"JEFF",  "JERK",  "JESS",  "JEST",  "JIBE",  "JILL",  "JILT",  "JIVE",
+"JOAN",  "JOBS",  "JOCK",  "JOEL",  "JOEY",  "JOHN",  "JOIN",  "JOKE",
+"JOLT",  "JOVE",  "JUDD",  "JUDE",  "JUDO",  "JUDY",  "JUJU",  "JUKE",
+"JULY",  "JUNE",  "JUNK",  "JUNO",  "JURY",  "JUST",  "JUTE",  "KAHN",
+"KALE",  "KANE",  "KANT",  "KARL",  "KATE",  "KEEL",  "KEEN",  "KENO",
+"KENT",  "KERN",  "KERR",  "KEYS",  "KICK",  "KILL",  "KIND",  "KING",
+"KIRK",  "KISS",  "KITE",  "KLAN",  "KNEE",  "KNEW",  "KNIT",  "KNOB",
+"KNOT",  "KNOW",  "KOCH",  "KONG",  "KUDO",  "KURD",  "KURT",  "KYLE",
+"LACE",  "LACK",  "LACY",  "LADY",  "LAID",  "LAIN",  "LAIR",  "LAKE",
+"LAMB",  "LAME",  "LAND",  "LANE",  "LANG",  "LARD",  "LARK",  "LASS",
+"LAST",  "LATE",  "LAUD",  "LAVA",  "LAWN",  "LAWS",  "LAYS",  "LEAD",
+"LEAF",  "LEAK",  "LEAN",  "LEAR",  "LEEK",  "LEER",  "LEFT",  "LEND",
+"LENS",  "LENT",  "LEON",  "LESK",  "LESS",  "LEST",  "LETS",  "LIAR",
+"LICE",  "LICK",  "LIED",  "LIEN",  "LIES",  "LIEU",  "LIFE",  "LIFT",
+"LIKE",  "LILA",  "LILT",  "LILY",  "LIMA",  "LIMB",  "LIME",  "LIND",
+"LINE",  "LINK",  "LINT",  "LION",  "LISA",  "LIST",  "LIVE",  "LOAD",
+"LOAF",  "LOAM",  "LOAN",  "LOCK",  "LOFT",  "LOGE",  "LOIS",  "LOLA",
+"LONE",  "LONG",  "LOOK",  "LOON",  "LOOT",  "LORD",  "LORE",  "LOSE",
+"LOSS",  "LOST",  "LOUD",  "LOVE",  "LOWE",  "LUCK",  "LUCY",  "LUGE",
+"LUKE",  "LULU",  "LUND",  "LUNG",  "LURA",  "LURE",  "LURK",  "LUSH",
+"LUST",  "LYLE",  "LYNN",  "LYON",  "LYRA",  "MACE",  "MADE",  "MAGI",
+"MAID",  "MAIL",  "MAIN",  "MAKE",  "MALE",  "MALI",  "MALL",  "MALT",
+"MANA",  "MANN",  "MANY",  "MARC",  "MARE",  "MARK",  "MARS",  "MART",
+"MARY",  "MASH",  "MASK",  "MASS",  "MAST",  "MATE",  "MATH",  "MAUL",
+"MAYO",  "MEAD",  "MEAL",  "MEAN",  "MEAT",  "MEEK",  "MEET",  "MELD",
+"MELT",  "MEMO",  "MEND",  "MENU",  "MERT",  "MESH",  "MESS",  "MICE",
+
+
+
+Haller                      Standards Track                    [Page 22]
+
+RFC 2289               A One-Time Password System          February 1998
+
+
+"MIKE",  "MILD",  "MILE",  "MILK",  "MILL",  "MILT",  "MIMI",  "MIND",
+"MINE",  "MINI",  "MINK",  "MINT",  "MIRE",  "MISS",  "MIST",  "MITE",
+"MITT",  "MOAN",  "MOAT",  "MOCK",  "MODE",  "MOLD",  "MOLE",  "MOLL",
+"MOLT",  "MONA",  "MONK",  "MONT",  "MOOD",  "MOON",  "MOOR",  "MOOT",
+"MORE",  "MORN",  "MORT",  "MOSS",  "MOST",  "MOTH",  "MOVE",  "MUCH",
+"MUCK",  "MUDD",  "MUFF",  "MULE",  "MULL",  "MURK",  "MUSH",  "MUST",
+"MUTE",  "MUTT",  "MYRA",  "MYTH",  "NAGY",  "NAIL",  "NAIR",  "NAME",
+"NARY",  "NASH",  "NAVE",  "NAVY",  "NEAL",  "NEAR",  "NEAT",  "NECK",
+"NEED",  "NEIL",  "NELL",  "NEON",  "NERO",  "NESS",  "NEST",  "NEWS",
+"NEWT",  "NIBS",  "NICE",  "NICK",  "NILE",  "NINA",  "NINE",  "NOAH",
+"NODE",  "NOEL",  "NOLL",  "NONE",  "NOOK",  "NOON",  "NORM",  "NOSE",
+"NOTE",  "NOUN",  "NOVA",  "NUDE",  "NULL",  "NUMB",  "OATH",  "OBEY",
+"OBOE",  "ODIN",  "OHIO",  "OILY",  "OINT",  "OKAY",  "OLAF",  "OLDY",
+"OLGA",  "OLIN",  "OMAN",  "OMEN",  "OMIT",  "ONCE",  "ONES",  "ONLY",
+"ONTO",  "ONUS",  "ORAL",  "ORGY",  "OSLO",  "OTIS",  "OTTO",  "OUCH",
+"OUST",  "OUTS",  "OVAL",  "OVEN",  "OVER",  "OWLY",  "OWNS",  "QUAD",
+"QUIT",  "QUOD",  "RACE",  "RACK",  "RACY",  "RAFT",  "RAGE",  "RAID",
+"RAIL",  "RAIN",  "RAKE",  "RANK",  "RANT",  "RARE",  "RASH",  "RATE",
+"RAVE",  "RAYS",  "READ",  "REAL",  "REAM",  "REAR",  "RECK",  "REED",
+"REEF",  "REEK",  "REEL",  "REID",  "REIN",  "RENA",  "REND",  "RENT",
+"REST",  "RICE",  "RICH",  "RICK",  "RIDE",  "RIFT",  "RILL",  "RIME",
+"RING",  "RINK",  "RISE",  "RISK",  "RITE",  "ROAD",  "ROAM",  "ROAR",
+"ROBE",  "ROCK",  "RODE",  "ROIL",  "ROLL",  "ROME",  "ROOD",  "ROOF",
+"ROOK",  "ROOM",  "ROOT",  "ROSA",  "ROSE",  "ROSS",  "ROSY",  "ROTH",
+"ROUT",  "ROVE",  "ROWE",  "ROWS",  "RUBE",  "RUBY",  "RUDE",  "RUDY",
+"RUIN",  "RULE",  "RUNG",  "RUNS",  "RUNT",  "RUSE",  "RUSH",  "RUSK",
+"RUSS",  "RUST",  "RUTH",  "SACK",  "SAFE",  "SAGE",  "SAID",  "SAIL",
+"SALE",  "SALK",  "SALT",  "SAME",  "SAND",  "SANE",  "SANG",  "SANK",
+"SARA",  "SAUL",  "SAVE",  "SAYS",  "SCAN",  "SCAR",  "SCAT",  "SCOT",
+"SEAL",  "SEAM",  "SEAR",  "SEAT",  "SEED",  "SEEK",  "SEEM",  "SEEN",
+"SEES",  "SELF",  "SELL",  "SEND",  "SENT",  "SETS",  "SEWN",  "SHAG",
+"SHAM",  "SHAW",  "SHAY",  "SHED",  "SHIM",  "SHIN",  "SHOD",  "SHOE",
+"SHOT",  "SHOW",  "SHUN",  "SHUT",  "SICK",  "SIDE",  "SIFT",  "SIGH",
+"SIGN",  "SILK",  "SILL",  "SILO",  "SILT",  "SINE",  "SING",  "SINK",
+"SIRE",  "SITE",  "SITS",  "SITU",  "SKAT",  "SKEW",  "SKID",  "SKIM",
+"SKIN",  "SKIT",  "SLAB",  "SLAM",  "SLAT",  "SLAY",  "SLED",  "SLEW",
+"SLID",  "SLIM",  "SLIT",  "SLOB",  "SLOG",  "SLOT",  "SLOW",  "SLUG",
+"SLUM",  "SLUR",  "SMOG",  "SMUG",  "SNAG",  "SNOB",  "SNOW",  "SNUB",
+"SNUG",  "SOAK",  "SOAR",  "SOCK",  "SODA",  "SOFA",  "SOFT",  "SOIL",
+"SOLD",  "SOME",  "SONG",  "SOON",  "SOOT",  "SORE",  "SORT",  "SOUL",
+"SOUR",  "SOWN",  "STAB",  "STAG",  "STAN",  "STAR",  "STAY",  "STEM",
+"STEW",  "STIR",  "STOW",  "STUB",  "STUN",  "SUCH",  "SUDS",  "SUIT",
+"SULK",  "SUMS",  "SUNG",  "SUNK",  "SURE",  "SURF",  "SWAB",  "SWAG",
+"SWAM",  "SWAN",  "SWAT",  "SWAY",  "SWIM",  "SWUM",  "TACK",  "TACT",
+"TAIL",  "TAKE",  "TALE",  "TALK",  "TALL",  "TANK",  "TASK",  "TATE",
+"TAUT",  "TEAL",  "TEAM",  "TEAR",  "TECH",  "TEEM",  "TEEN",  "TEET",
+"TELL",  "TEND",  "TENT",  "TERM",  "TERN",  "TESS",  "TEST",  "THAN",
+"THAT",  "THEE",  "THEM",  "THEN",  "THEY",  "THIN",  "THIS",  "THUD",
+
+
+
+Haller                      Standards Track                    [Page 23]
+
+RFC 2289               A One-Time Password System          February 1998
+
+
+"THUG",  "TICK",  "TIDE",  "TIDY",  "TIED",  "TIER",  "TILE",  "TILL",
+"TILT",  "TIME",  "TINA",  "TINE",  "TINT",  "TINY",  "TIRE",  "TOAD",
+"TOGO",  "TOIL",  "TOLD",  "TOLL",  "TONE",  "TONG",  "TONY",  "TOOK",
+"TOOL",  "TOOT",  "TORE",  "TORN",  "TOTE",  "TOUR",  "TOUT",  "TOWN",
+"TRAG",  "TRAM",  "TRAY",  "TREE",  "TREK",  "TRIG",  "TRIM",  "TRIO",
+"TROD",  "TROT",  "TROY",  "TRUE",  "TUBA",  "TUBE",  "TUCK",  "TUFT",
+"TUNA",  "TUNE",  "TUNG",  "TURF",  "TURN",  "TUSK",  "TWIG",  "TWIN",
+"TWIT",  "ULAN",  "UNIT",  "URGE",  "USED",  "USER",  "USES",  "UTAH",
+"VAIL",  "VAIN",  "VALE",  "VARY",  "VASE",  "VAST",  "VEAL",  "VEDA",
+"VEIL",  "VEIN",  "VEND",  "VENT",  "VERB",  "VERY",  "VETO",  "VICE",
+"VIEW",  "VINE",  "VISE",  "VOID",  "VOLT",  "VOTE",  "WACK",  "WADE",
+"WAGE",  "WAIL",  "WAIT",  "WAKE",  "WALE",  "WALK",  "WALL",  "WALT",
+"WAND",  "WANE",  "WANG",  "WANT",  "WARD",  "WARM",  "WARN",  "WART",
+"WASH",  "WAST",  "WATS",  "WATT",  "WAVE",  "WAVY",  "WAYS",  "WEAK",
+"WEAL",  "WEAN",  "WEAR",  "WEED",  "WEEK",  "WEIR",  "WELD",  "WELL",
+"WELT",  "WENT",  "WERE",  "WERT",  "WEST",  "WHAM",  "WHAT",  "WHEE",
+"WHEN",  "WHET",  "WHOA",  "WHOM",  "WICK",  "WIFE",  "WILD",  "WILL",
+"WIND",  "WINE",  "WING",  "WINK",  "WINO",  "WIRE",  "WISE",  "WISH",
+"WITH",  "WOLF",  "WONT",  "WOOD",  "WOOL",  "WORD",  "WORE",  "WORK",
+"WORM",  "WORN",  "WOVE",  "WRIT",  "WYNN",  "YALE",  "YANG",  "YANK",
+"YARD",  "YARN",  "YAWL",  "YAWN",  "YEAH",  "YEAR",  "YELL",  "YOGA",
+"YOKE"   };
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Haller                      Standards Track                    [Page 24]
+
+RFC 2289               A One-Time Password System          February 1998
+
+
+Full Copyright Statement
+
+   Copyright (C) The Internet Society (1998).  All Rights Reserved.
+
+   This document and translations of it may be copied and furnished to
+   others, and derivative works that comment on or otherwise explain it
+   or assist in its implementation may be prepared, copied, published
+   and distributed, in whole or in part, without restriction of any
+   kind, provided that the above copyright notice and this paragraph are
+   included on all such copies and derivative works.  However, this
+   document itself may not be modified in any way, such as by removing
+   the copyright notice or references to the Internet Society or other
+   Internet organizations, except as needed for the purpose of
+   developing Internet standards in which case the procedures for
+   copyrights defined in the Internet Standards process must be
+   followed, or as required to translate it into languages other than
+   English.
+
+   The limited permissions granted above are perpetual and will not be
+   revoked by the Internet Society or its successors or assigns.
+
+   This document and the information contained herein is provided on an
+   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
+   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
+   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
+   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
+   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
+
+
+
+
+
+
+
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+
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+
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+
+
+
+Haller                      Standards Track                    [Page 25]
+