9,834 reputation
12450
bio website github.com/CodesInChaos
location Frankfurt, Germany
age
visits member for 3 years, 3 months
seen 1 hour ago

Oct
10
comment Hash functions throughput performance
On what platform? And what kind of implementation? Some hashes need c with SIMD intrinsics to shine, some are okay with plain c. Some require 64 bit CPUs, some excel in hardware (ASIC or FPGA). There is no single fastest hash.
Oct
9
comment what are the uses of tweaks in block ciphers?
@sashank You can encrypt each block independently, similar to ECB mode. But the tweak ensures that the same data at different positions encrypts to different values, avoiding ECB's biggest weakness.
Oct
9
comment AES file encryption with PBKDF2. Safe parameters?
@hunter Not entirely sure what you mean by "only the final round". Do you want to run PBKDF2 with 1 iteration on the output of PBKDF2 with many iterations?
Oct
9
comment post-quantum threshold secret sharing
Hashes/one-way-functions are a completely different issue. As far as we can tell they still exist, you just need to use twice the size. A 512 bit hash will offer 256 bits of security against QCs, far from any realistic attack.
Oct
9
comment post-quantum threshold secret sharing
If by threshold secret sharing, you mean something like Shamir's secret sharing, you can continue to use it. It's secure against computationally unbounded attackers i.e. it offers information theoretic security. It's essentially a system with less equations than variables, so there are many equally likely solutions.
Oct
9
comment AES file encryption with PBKDF2. Safe parameters?
@hunter one has to be careful about that. If one directly requests more than the natural size from PBKDF2 it can increase the cost for the defender but not for the attacker. Personally I like HKDF-Expand for this step.
Oct
9
comment what are the uses of tweaks in block ciphers?
I've only seen tweaks used as a block counter.
Oct
9
reviewed Approve suggested edit on disk-encryption tag wiki
Oct
9
reviewed Approve suggested edit on matrix-multiplication tag wiki excerpt
Oct
9
reviewed Approve suggested edit on multiple-encryption tag wiki excerpt
Oct
9
reviewed Approve suggested edit on matrix-multiplication tag wiki
Oct
9
reviewed Approve suggested edit on multiple-encryption tag wiki
Oct
9
reviewed Approve suggested edit on disk-encryption tag wiki excerpt
Oct
9
comment AES file encryption with PBKDF2. Safe parameters?
1024 iterations is very low. If you can afford the performance hit, use a larger value. On a desktop computer you should be able to afford a million iterations.
Oct
8
comment How do TLS 1.1 and 1.2 generate IVs (initialization vectors) for each record?
The obvious implementation is requesting 16 bytes from the PRNG.
Oct
8
comment How does redundancy in a file effects performance and security of encryption?
Proper encryption doesn't notice redundancy. You're putting in a bunch of bytes, getting out a bunch of bytes and runtime only depends on the length of the input.
Oct
8
awarded  Nice Question
Oct
8
comment Does BouncyCastle (for ECC) resist timing attacks?
I wouldn't use the ECC code in BouncyCastle C#.
Oct
8
comment How does one use AES block cipher modes of operation?
I don't get your question. You say that you have 8 bit block size, but you also mention AES. That makes no sense. Do you mean that you need to encrypt messages which aren't a multiple of 128 bits without length increase?
Oct
8
reviewed Approve suggested edit on timestamping tag wiki