I asked a question somewhere else on stack exchange and had to put something like "using the numerical one time pad the user can create their encrypted message by hand". Is there a better way of saying "numerical one time pad"?

The following is an example of what I'm trying to describe:
key: 7 1 6 3 1 3
message: 0 5 0 9 9 9
ciphertext = (message + key) mod 10: 7 6 6 2 0 2

Most OTP examples use mod 26, and most computer programs use mod 2 (XOR), but I'm trying to describe encrypting a decimal number specifically.

  • $\begingroup$ Xor is lighting fast. Is there any advantage for using decimal number? $\endgroup$
    – Leo.W
    Commented Feb 24, 2017 at 10:49
  • $\begingroup$ "decimal-based OTP"? $\endgroup$
    – SEJPM
    Commented Feb 24, 2017 at 10:55
  • 1
    $\begingroup$ @DY.W an XOR function is likely faster for computers but this is for a human to write out by hand. The advantage is a human can do this quickly without converting to binary and converting back, since they have been trained to do math in base 10 already. $\endgroup$
    – daniel
    Commented Feb 24, 2017 at 11:18
  • 2
    $\begingroup$ @SEJPM "decimal one-time-pad" - as not to confuse it with "(decimal) one-time-password"? $\endgroup$
    – Maarten Bodewes
    Commented Feb 24, 2017 at 14:28
  • $\begingroup$ "Addition modulo 10", maybe... $\endgroup$
    – poncho
    Commented Feb 24, 2017 at 17:26

1 Answer 1


The correct names are OTLP (one time letter pad) and OTFP (one time figure pad). More about the system here:


  • $\begingroup$ I don't really like the word figure since its just a more important number. And i don't like like those tables. tables are gross. $\endgroup$
    – daniel
    Commented Feb 24, 2017 at 20:53
  • $\begingroup$ Well, OTLP and OTFP is what they are called. Is there reason not to like settled cryptographic expressions and giving things new names? Wouldn't it complicate things a bit too much if we all gave our own names to everything of which we don't like the name. We'd create babylon, everybody talking differently. What's wrong with what tables? $\endgroup$ Commented Feb 24, 2017 at 22:53
  • $\begingroup$ There are like 6 google results for "one time figure pad" versus a quarter of a million for one time pad.\ $\endgroup$
    – daniel
    Commented Feb 24, 2017 at 23:44
  • $\begingroup$ Well, the one time pad is the general name that is known to the public. A few decades ago, most people even never heard of one time pad. It's not because "one time pad" is popular that there are no other expression used in the branche. I can give you many expressions you never heard of, but that doesn't mean they are not correct. Do you have any experience with crypto? 10 years ago nobody ever heard of the TSEC/KL7. Is that a reason not to like it? That's why people take the effort to document these things. Otherwise, we live in a world where "i don't know it" means "it doesn't exist" ;-) $\endgroup$ Commented Feb 25, 2017 at 8:51

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