10,257 reputation
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bio website github.com/CodesInChaos
location Frankfurt, Germany
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visits member for 3 years, 5 months
seen 2 hours ago

Jan
6
revised Why xor the message into the state for sponge hashes?
added 136 characters in body
Jan
6
asked Why xor the message into the state for sponge hashes?
Jan
5
comment RSA 4096 bit key benchmark
@owlstead Personally I like Curve25519/Ed25519 a lot. Quite fast, no timing attacks, compressed points(no validation required) and no random numbers for signing. It's no NIST standard, but that doesn't matter for my personal projects.
Jan
4
comment Does Grover's algorithm effect block size or only key size?
What do you mean by "protocol size"?
Jan
4
revised Calculating RSA private exponent when given public exponent and the modulus factors using extended euclid
edited title
Jan
4
comment Does Grover's algorithm effect block size or only key size?
1) I don't see that paper mentioning Rijndael with 256 bit blocks at all. It talks about AES with 128 bit blocks. AES-256 has a 256 bit key and 128 bit blocks. 2) Summarizing the paper as "AES-256 is not secure" is highly misleading. Related key attacks are irrelevant for pretty much every protocol that uses AES. 3) "Grover [...] cracking symmetric keys 2x faster" That's wrong too. A 2x speedup would be completely harmless. Grover halves the effective key-length, which is an exponential speedup.
Jan
3
comment Calculating RSA private exponent when given public exponent and the modulus factors using extended euclid
Check the "Computing a multiplicative inverse in a finite field" section of the "Extended Euclidean algorithm" wikipedia article.
Jan
3
awarded  Enlightened
Jan
2
revised How will Cryptography be changed by Quantum Computing?
formatting
Jan
1
comment Determining the algorithm used to generate a digital signature
I'd try throwing some kind of ASN1 parser at the signature.
Dec
30
answered Difference between symmetric and asymmetric hash function?
Dec
30
comment Difference between symmetric and asymmetric hash function?
That isn't about asymmetric hashes, but about asynchronous implementations of symmetric hashes. The code doesn't contain the word asymmetric anywhere. | Async in that context means that you order some computation, then do something else, and once the computation is finished(probably on another thread) you receive the result.
Dec
30
comment Difference between symmetric and asymmetric hash function?
There is symmetric(AES) and asymmetric(RSA) encryption. And there is symmetric authentication(MAC) and asymmetric authentication(RSA signatures). Many authentication schemes use hashes, but they aren't hashes.
Dec
30
comment Difference between symmetric and asymmetric hash function?
Can you provide some source for that claim? I've never heard of asymmetric hash functions. Hashes like SHA-x are unkeyed and symmetric.
Dec
30
comment Is RSASSA-PKCS1-v1_5 a good signature scheme for new systems?
It's important to note that PSS isn't broken when used without randomness, the security reduction just becomes less tight.
Dec
30
comment Is RSASSA-PKCS1-v1_5 a good signature scheme for new systems?
It's very important not to confuse RSASSA-PKCS1-v1_5 (the signature system) and RSAES-PKCS1-v1_5 (the encryption system). The latter is very broken in practice. Do not use RSAES-PKCS1-v1_5!
Dec
26
comment What exactly is a negligible (and non-negligible) function?
Asymptotic security claims aren't that popular nowadays. Concrete security claims are preferred, because they make a statement about the concrete key sizes we use.
Dec
25
comment Why does Fortuna (RNG) require entropy sources to specify accumulator pool?
I still don't get your argument. Since the benign sources have separate counters that the evil source can't influence, the input from the begin sources is still evenly distributed no matter what the evil sources do.
Dec
24
comment Why does Fortuna (RNG) require entropy sources to specify accumulator pool?
"Seems like that would make it harder for an evil entropy source to influence particular pools" what do you mean by that?
Dec
24
answered Why does Fortuna (RNG) require entropy sources to specify accumulator pool?