Tagged Questions
9
votes
2answers
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Why is the salt used only once in PBKDF2, while the password is used often?
The purpose of PBKDF2 is to create a derived key (DK) from a master password (PW) and a salt, often using a function like HMAC-SHA256. I have read that the salt should be as random as possible. But ...
10
votes
1answer
337 views
Security of N bit HMAC
Lets say that I am using 128 bit HMAC. How many operations are needed to find "non secure" message. Is birthday attack possible?
