Plaintexts

Unlike differential cryptanalysis, which uses pairs of chosen plaintexts with a fixed XOR difference, integral cryptanalysis uses sets or even multisets of chosen plaintexts of which part is held constant and another part varies through all possibilities.

Working back and forth between the two plaintexts, using the intelligibility criterion to check guesses, the analyst may recover much or all of the original plaintexts.

A cryptosystem is called semantically secure if an attacker cannot distinguish two encryptions from each other even if the attacker knows (or has chosen) the corresponding plaintexts.

All such ciphers are easier to break than once believed, as substitution alphabets are repeated for sufficiently large plaintexts.

If both plaintexts are in a natural language (e.

If the attacker seeks to discover any one of many cryptographic keys, there is a memory-efficient attack which will discover one of 2 28 keys, given a handful of chosen plaintexts per key and around 2 84 encryption operations.

In other cases, the plaintext can be contrived to have a nearly flat frequency distribution, and much longer plaintexts will then be required by the user.

This padding ensures that m does not fall into the range of insecure plaintexts, and that a given message, once padded, will encrypt to one of a large number of different possible ciphertexts.

Trying all keys simply yields all plaintexts, all equally likely to be the actual plaintext.