Quantum attacks against iterated block ciphers

Understand

We study the amplification of security against quantum attacks provided by iteration of block ciphers.

• In the classical case, the Meet-in-the-middle attack is a generic attack against those constructions.
• This attack reduces the time required to break double iterations to only twice the time it takes to attack a single block cipher, given that the attacker has access to a large amount of memory.
• More abstractly, it shows that security by composition does not achieve exact multiplicative amplification.