Army signals security & "Clansmen" series radios

[David Howe]

> Yes, but if there are 10,000 recipients it will take forever to generate
> the encryptions, and the size of each message will be huge (yes, I know
> you only have to encrypt the session key, but 10,000 encrypted session
> keys is still a lot of data to have to transmit).
  Worse than that - in order for the message to be a true variant (for
reverse-tracking) there must be a unique difference betwen each one (in the
plaintext, not the structure), or at best a small subset of different
messages (say ten) which are allocated diffferently with each group
transmission so as to "home in" on the guilty party (which still allows a
source with access to two or more leaks to discover and remove/alter the
pattern).
  However, this approach is often discounted in practice as both ends of the
game know it is possible, so rephrase and rearrange the message as much as
possible before passing it beyond the leak's handler.