3,984 reputation
11032
bio website bradconte.com
location Texas, USA
age 27
visits member for 3 years, 3 months
seen Nov 11 at 6:49

I'm a software engineer with a background in computer science and mathematics. I love cryptography, math, and Linux.

More about me on my website: http://bradconte.com/about.


Oct
23
reviewed No Action Needed Open source implementations of Symmetric Searchable Encryption and Order Preserving Encryption
Oct
23
reviewed No Action Needed How is SSL secure from rogue Certificate Authorities?
Oct
23
reviewed Close Are there any hand ciphers not obsoleted by computer cryptanalysis?
Oct
23
revised Would it be possible to generate the original data from a SHA-512 checksum?
added 286 characters in body
Oct
23
answered Would it be possible to generate the original data from a SHA-512 checksum?
Oct
23
revised Guarding against cryptanalytic breakthroughs: combining multiple hash functions
Corrected dead link, inserted paper title.
Oct
19
comment Does encrypting a hash of the message yield a secure MAC?
@pasgabriele: I don't know know for sure, but it seems reasonable. It would be very useful for this question to have that answered. If nothing else, with a fixed CBC IV you would be using CBC-MAC on the message hash. Signatures usually just sign a hash, MACing just the hash should be acceptable too.
Oct
19
reviewed Approve suggested edit on blocksize tag wiki excerpt
Oct
19
reviewed Approve suggested edit on blocksize tag wiki
Oct
18
comment Does encrypting a hash of the message yield a secure MAC?
@nightcracker: I'm not sure that's a necessary property of MACs. Avoiding leaking $x_0 = x_1$ is a requirement of confidentiality, not authentication. And in practice, the randomized ciphertext of both MTE and ETM will randomize the MAC. (And if you aren't encrypting, the point is moot.)
Oct
18
comment Does encrypting a hash of the message yield a secure MAC?
@pasgabriele: A PRF is a suitable MAC. Your question is probably best posed as: Is $PRP(hash(x))$ a PRF? Considering that a PRP is a PRF for hash-output sized inputs, this seams plausible at the outset.
Oct
18
comment Does encrypting a hash of the message yield a secure MAC?
@nightcracker: Which messages produce the same MAC (with non-negligible probability)? The provided example only finds intermediate values for doing so.
Oct
18
comment Two different approaches for Key Expansion using the AES-256 algorithm?
Good catch. I copied the code from the OP, I don't know why there is + notation. The actual algorithm uses the XOR operation, so maybe those instances should be changed to ^ for clarity. I assume they were intended to indicate the same thing.
Oct
17
awarded  Cleanup
Oct
17
revised Two different approaches for Key Expansion using the AES-256 algorithm?
rolled back to a previous revision
Oct
17
revised Two different approaches for Key Expansion using the AES-256 algorithm?
Moved re-written code into answer, tweaked other wording.
Oct
17
answered Two different approaches for Key Expansion using the AES-256 algorithm?
Oct
17
revised Two different approaches for Key Expansion using the AES-256 algorithm?
deleted 97 characters in body
Oct
16
revised Two different approaches for Key Expansion using the AES-256 algorithm?
Use bracket-style subscripting for a "w" values, to simplify the notation.
Oct
16
reviewed Approve suggested edit on predicate-encryption tag wiki