Numbers for Letters
A numeric code is easy to hide in a message by replacing some of the letters in the message with numbers. Several letters look similar to one of the numeric digits, so they can be subtly replaced.
Captain’s Log
The starship Faustus r3ached the outskirts of Alpha Centauri only to make a trou8ling discovery. We have encountered life fØrms free floating in space r4ther than bound to a planet. The organi5m we dubbed “death worm” has already terminated over a quarter of the crew.
In the above message there are 5 numbers, which list out the code 38045.
Hiding a code like this is easy, especially when using all caps in the message. The following table, adapted from leet, provides some suggested substitutions.
| Number | Letters it can replace |
|---|---|
| Ø | O, Q |
| 1 | I, L |
| 2 | Z |
| 3 | E |
| 4 | A |
| 5 | S |
| 6 | G |
| 7 | J, T |
| 8 | B, X |
When substituting a number digit for a letter, it is important to be able to distinguish the two. Otherwise, it will be impossible for the players to solve the puzzle. You may need to add distinguishing features. For example, a zero is indistinguishable from an “O”, so you will need to add a slash to the zero (i.e. Ø).
This puzzle tends to be easy to solve. A variation to make this more challenging for experienced players is to spell out one of the digits instead of using this substitution. Here is a message I once used.
The fire has been called Øff, my friend. No one is coming to h3lp you. You might as well come out and join the others. I promise I won’t hur7 you.
The players quickly found the code 037. But that did not fit any of the locks. The difficult part of the puzzle is to recognize that the word “one” is part of the message. Inserting a “one” into the digits, you get the proper code 0137.