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bio website github.com/CodesInChaos
location Frankfurt, Germany
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visits member for 3 years, 4 months
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Dec
2
comment What is the function of the secret key “r” in Poly1305?
$r$ being secret is essential. The only point of $s$ is to prevent an attacker from learning $r$.
Nov
30
comment Why is Lamport-Diffie secure?
As far as we know, there there are collision resistant hashes (if necessary we can even weaken that to random prefix collision resistance) which resist quantum computers with slightly larger security parameter.
Nov
29
comment are ideal hashes possible to create?
If your definition of "ideal hash" is that it has no collisions with an input larger than the output, that's impossible. Pigeonhole principle
Nov
28
comment Convert a number to sha-1
I don't get your point regarding collisions. But 2^44 should be feasible as a one-time effort, the rainbow table is only used to make additional conversions cheaper.
Nov
28
reviewed Approve suggested edit on hybrid tag wiki excerpt
Nov
28
reviewed Approve suggested edit on md2 tag wiki excerpt
Nov
28
reviewed Approve suggested edit on hybrid tag wiki
Nov
28
reviewed Approve suggested edit on
Nov
28
reviewed Approve suggested edit on access-control tag wiki
Nov
28
reviewed Approve suggested edit on constants tag wiki excerpt
Nov
28
reviewed Approve suggested edit on access-control tag wiki excerpt
Nov
28
reviewed Approve suggested edit on md2 tag wiki
Nov
28
reviewed Approve suggested edit on constants tag wiki
Nov
28
reviewed Approve suggested edit on
Nov
28
comment Design requirements for a keyed hash function?
The hash function needs to collision resistant. The encryption is trickier. Authenticated encryption always works (but that's a bit of cheating). An unauthenticated stream cipher does not work. A raw blockcipher with same block size as the hash does work.
Nov
28
comment Design requirements for a keyed hash function?
Related question: Is the encryption of a hash a good MAC?
Nov
28
comment Convert a number to sha-1
Searching a fixed 44 bit space might actually be one of the rare situations where a rainbow table is useful.
Nov
28
comment TCR hash functions from MD5
MD5 being broken only means that an attacker can find collisions when its used without a key.
Nov
27
reviewed Approve suggested edit on The exact definition of a symmetric encryption
Nov
27
comment scrypt and bcrypt for benefits of both?
For bcrypt and PBKDF2 combining them with each having have the work factor wouldn't really matter. For scrypt it's different: If you're CPU and not memory bound (typical for server side hashing), doubling the time budget doubles the used memory as well, making it four times as hard to break. => scrypt benefits from being the only function you use