9,751 reputation
12448
bio website github.com/CodesInChaos
location Frankfurt, Germany
age
visits member for 3 years, 2 months
seen 3 hours ago

Oct
8
reviewed Approve suggested edit on timestamping tag wiki excerpt
Oct
8
reviewed Approve suggested edit on fortuna tag wiki
Oct
8
reviewed Approve suggested edit on fortuna tag wiki excerpt
Oct
7
comment Does ElGamal Encryption create a different key for each block sent?
cross-posted on SO
Oct
7
comment SHA-1 colission resistance proof
Those are essentially random numbers, but created in a way that doesn't allow the algorithm designer to choose them, so called Nothing up my sleeve numbers. I don't remember what SHA-1 chose, probably the first few hex digits of square-root of a small prime.
Oct
7
comment SHA-1 colission resistance proof
1) It isn't 2) Those properties generally don't have a proof.
Oct
7
comment Why are huge prime numbers important in cryptography?
Huge primes are not important in crypto. I've never seen a prime larger than 10000 bits in crypto. Finding huge primes is just a sport.
Oct
6
comment Does BouncyCastle (for ECC) resist timing attacks?
These are large libraries, some parts my be better than others. At least the ECC part looks vulnerable to timing attacks to me.
Oct
6
comment Practical disadvantages of GCM mode encryption
That kind of bug can happen with pretty much any kind of MAC. They're the reason why I like unit tests that cover all possible message length from 0 to a few hundred.
Oct
6
answered How does one deal with a negative “d” in RSA?
Oct
6
comment What is adversary's advantage in cryptography and why we use it?
@LateralFractal I'd guess having a site-index (which tells google what has changed) and being popular are the most important factors.
Oct
6
comment Is this a good entropy collector and whitening technique?
A sane algorithm would be secure if the entire seed material contained enough (somewhere between 100 and 200 bits) entropy. Your algorithm is only secure if each 512 bit block contains enough entropy. So it's clearly a bad design.
Oct
6
comment Is this a good entropy collector and whitening technique?
Step 3 is silly, and step 5 shows a misunderstanding of randomness
Oct
5
comment Is there a way to make RC4 (ARCFOUR) secure, or is it completely broken?
@e-sushi At the lower level I mostly use NaCl stuff, but at the higher levels I like homebrew stuff, for example designing my own SSL alternative. I don't like TLS or GPG much. I tell people to use TLS, but I don't like using it myself, so I'm a bit of a hypocrite.
Oct
4
revised Hashing a message with a length that isn't a multiple of 8 bits
edited title
Oct
4
revised Decrypting a message without the private key using CRT
added 13 characters in body
Oct
4
comment NIST temporarily closed — will that have a negative impact on the future of cryptography?
Avoiding NIST standards just because they come from NIST isn't that useful. We need to understand why they're broken. Without that understanding we can't know if alternatives aren't just as bad.
Oct
4
comment Three-way hash collision
For narrow pipe (or even local wide-pipe) constructions you'll get a four-way hash collision for merely the cost of two normal collisions.
Oct
4
comment Difference between salted hash and keyed hashing?
A key is secret, a salt is not.
Oct
3
comment Extracting only the entropy
@Blaze /dev/random is no good. Its performance sucks. Because for some reason it tries to limit the output to the estimated entropy.