6 ms·
Is that really a fair characterization? The two-time pad is like Vigenere with a very long key. Offhand, I'd expect that makes the cryptanalysis much more cha
by cvwright 8y ago
Is that really a fair characterization?
The two-time pad is like Vigenere with a very long key. Offhand, I'd expect that makes the cryptanalysis much more challenging than for Vigenere with a typical short key.
- deleted 8y ago[deleted]
- tptacek 8y agoI wrote a reply but then read 'SilasX's sibling and now I'm less sure of that reply. :) Key size is less interesting to me than the number of times the key is reused.
- a1369209993 8y ago> Is that really a fair characterization? Kind of, but not quite; the problem with a 2-time pad is key cancellation: c1 ^ c2 = (p1 ^ k) ^ (p2 ^ k) = p1 ^ p2. The xor[0] of two plaintexts is only challenging to cryptanalyze if high-entropy sensitive information happens to line up in just the right way. 0: Technically sum mod 26 or so - xor is sum mod 2 - but the same tricks apply.