Re: Encryption key longer than text to encrypt


Sebastian Gottschalk wrote:
Jean-François Michaud wrote:

All of this of course, depends on the initial rotor states being
unknown to the attackers.

And the initial state, which is the actual key, is shorter than the
message. Thus, it's still just a stream cipher.

Would it matter If the algorithm was known?

The algorithm *is* known to the attacker.

Hmmm my understanding of stream ciphers was based on incomplete
information. You're probably refering to the definition using
"keystream generation". It is much more accurate than the definition
that uses these criteria:

1- Symmetric cipher
2- Input digits are encrypted one at a time
3- The transformation of digits varies during the encryption

My cipher only solidly met the first criterion. Context is lacking for
the second and third criteria.

Alright so I'm talking about a synchronous stream cipher, but the
original question still remains unanswered.

Regards
Jean-Francois Michaud

.

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