1 files changed, 12 insertions, 9 deletions

diff --git a/lib/libotputil/lrfc2289-otp.c b/lib/libotputil/lrfc2289-otp.c
index 807c2da..1ba7828 100644
--- a/lib/libotputil/lrfc2289-otp.c
+++ b/lib/libotputil/lrfc2289-otp.c
@@ -85,20 +85,23 @@ otputil_otp_code(
    int               pos;
 
    assert(otp_pass != NULL);
-   assert(otp_seed != NULL);
 
    // check otp_seed
-   for(len = 0; ((otp_seed[len])); len++)
+   secret[0] = '\0';
+   if ((otp_seed))
    {
-      if (len > OTPUTIL_OTP_SEED_MAX_LEN)
-         return(-1);
-      if (!(isalnum(otp_seed[len])))
+      for(len = 0; ((otp_seed[len])); len++)
+      {
+         if (len > OTPUTIL_OTP_SEED_MAX_LEN)
+            return(-1);
+         if (!(isalnum(otp_seed[len])))
+            return(-1);
+         secret[len] = tolower(otp_seed[len]);
+      };
+      secret[len] = '\0';
+      if (len < OTPUTIL_OTP_SEED_MIN_LEN)
          return(-1);
-      secret[len] = tolower(otp_seed[len]);
    };
-   secret[len] = '\0';
-   if (len < OTPUTIL_OTP_SEED_MIN_LEN)
-         return(-1);
 
    // check otp_pass
    len = strlen(otp_pass);