P1619: editorial change #18
I'd like to add another request (#18) for a small editorial change of the
P1619 draft.
In the Annex C.1. the word "random" and "randomize" appears with different,
only later defined meanings. A footnote or a reference would be helpful for
the reader, to clarify that some usage of these words mean the following:
If an agent does not know the key K and the original plaintext P, then a
change of the ciphertext C = E_K(P) to C' will result in a decrypted
plaintext P' = D_K(C'), which cannot be distinguished by the agent from
true random, with significant certainty. (Details are in C3).
The standard meaning of "random" does not apply here, because the functions
used are deterministic, and the key K is fixed for the whole key scope.
It is also important to emphasize that if the two conditions does not hold,
that is, the agent knows K and/or something about P, he can get some
information about the change from C to C', like the fact that change has
happened, or what bits were flipped.