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visits member for 1 year, 10 months
seen Feb 13 at 14:22

Oct
9
comment One time pad key exchange
Or both parties are physically present to create or exchange the keys.
Oct
4
comment In layman's terms, how does Shor's algorithm work?
I'm not qualified to provide an answer, but the following article may be what you are seeking: arstechnica.com/security/2012/09/…
Oct
3
comment Using SHA-256 with different initial hash value
Thanks. I need to read your answer a few times, but this was the kind of insight I was seeking.
Sep
7
comment Why is the salt used only once in PBKDF2, while the password is used often?
I agree - repeatedly injecting low entropy into a hash function just doesn't seem "right". In addition, the last 256 bits of the SHA256 input will be zero (as Ki/Ko are defined to be 512 bits and SHA256 has a 256 bit output and a 512 bit block size); again adding low entropy to the function. If I were to design a PBKDF I'd want to inject as much entropy as possible, but I also agree with the disclaimer.
Sep
6
comment Why is the salt used only once in PBKDF2, while the password is used often?
Correct. I understand the HMAC construction (which is really more of a workaround to address the length-extension attack weaknesses common to Merkle–Damgård construction hash functions), but the Un = PRF( PW, Un-1 ) construction is specific to PBKDF2. If just happens that if the PRF is an HMAC then the PW (which is typically short & low entropy) is used far more than the salt (which may have much better properties).
Sep
6
comment Why is the salt used only once in PBKDF2, while the password is used often?
Danke kind sir.