[syntheticnature]

The Discordians promulgated a code that might be a bit more mathematically resistant. It involves this series of steps:

  CONVERSION:
  A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

  STEP 1. Write out the message (HAIL ERIS) and put all the vowels at the end (HLRSAIEI)

  STEP 2. Reverse order (IEIASRLH)

  STEP 3. Convert to numbers (9-5-9-1-19-18-12-8)

  STEP 4. Put into numerical order (1-5-8-9-9-12-18-19)

  STEP 5. Convert back to letters (AEHIILRS)

They assert 100% unbreakability, which isn't true, but on a sufficiently long message one's anagram checker might give out, and then there is the task of ordering the words so generated...

Mind you, decryption by the intended recipient is equally complex.

[philh]

Not 100% unbreakable in general, but I think it does pretty well in the real world. There are plenty of messages that Eve simply can't decrypt with complete confidence. For example, she can't tell ATTACK WILL AT DAWN from ATTACK DAWN AT WILL. She'd have to resort to priors to guess which of those was intended.

[aparent]

It is so good that even Alice can't decrypt those with confidence! :)

[wanderfowl]

It's the newest, hottest thing in Crypto: Perfect Backwards Secrecy!

[wolfgke]

This algorithm can be simplified - step 2 can be skipped.

[watersb]

While technically correct, "simplified" is not part of the Discordian vocabulary.

[MatthaeusHarris]

The whole algorithm boils down to "Write your message into an array, then sort the array."