Take the 2-minute tour ×
Cryptography Stack Exchange is a question and answer site for software developers, mathematicians and others interested in cryptography. It's 100% free, no registration required.

there are two ways for key change: Key update and re-keying. Which of this methods use KDF (Key Derivation Function) for getting new keys.

share|improve this question
    
Both, as I recall they mean the same thing... –  user1028028 Feb 5 at 13:22
    
Difference between re-keying and key update is , that in case of re-keying the new key is independent of old key, in case of key update key is depend of old key. –  Gev_sedrakyan Feb 5 at 13:27
    
That would be bad ... as it might open the encryption to a related key attack... –  user1028028 Feb 5 at 13:34
    
Key update can still be dependent on the old key, but not be related on a cipher level, as you can run it through a KDF or hash algorithm. Just as re-key can use purely random data and not go through a KDF, either one can use or not use a KDF –  Richie Frame Feb 5 at 20:04

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.