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bio website github.com/CodesInChaos
location Frankfurt, Germany
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visits member for 3 years, 8 months
seen 11 hours ago

Mar
2
comment 128 bit 3DES Key and AES Key: what's the difference?
One of the annoying properties of DES is that you need to pass a 64 bit key to most implementations and it ignores 8 of them.
Mar
1
comment Are there any known weaknesses with ElGamal algorithm?
Take a look at ECIES, NaCl's boxes and axolotl.
Mar
1
comment Calculation of time needed to crack DES with my CPU
Brute-force is an embarrassingly parallel problem, so I'd expect a sequential CPU to do pretty badly, even with a bitsliced AVX2 implementation.
Mar
1
reviewed Reviewed Hashes and Ciphers
Mar
1
reviewed Edit How does knowing the factorization of N can help to obtain the secret?
Mar
1
revised How does knowing the factorization of N can help to obtain the secret?
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Mar
1
comment Twofish vs. Serpent vs. AES (or a combo)
The strength of the blockcipher is rarely the weakest point in a security system. There is no public cryptoanalysis that comes close to a practical break of AES. I use AES in TrueCrypt, since it's much faster than the others (thanks to AES-NI) and I consider it strong enough.
Mar
1
comment BLAKE2 input parameters
I don't see much point in using the salt feature, and AFAIK the reference implementation doesn't expose it. The third parameter is the key and what you want to use as key depends on what you're doing. It's pretty much the same thing as the key for HMAC or HKDF.
Mar
1
comment BLAKE2 input parameters
I'm voting to close this question as off-topic because this is a programming problem, not a cryptography problem.
Feb
27
comment Standard serialization format for libsodium-based messages
I'd use a simple version number and concatenation outside the box and a serialization library to produce the plaintext on the inside. Since you send this for every request, I'd use some compact encoding for the message (messagepack works if the keys are short) and I'd use (urlsafe) Base64 instead of hex. Finally I'd consider HMAC, since it doesn't require a nonce.
Feb
27
revised Drawback of ElGamal encryption
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Feb
27
comment Drawback of ElGamal encryption
Upsides compared with (EC)IES style schemes: None for normal encryption. Downsides: 1) Weak security proof (DDH) 2) Annoying to implement, since you need to be able to encode as group elements 3) malleable 4) The limited message size means that you typically still need to implement hybrid encryption.
Feb
27
comment Standard serialization format for libsodium-based messages
I'd simply concatenate nonce and ciphertext.
Feb
21
comment Figure out the encryption being used
If the algorithm doesn't suck, this will be impossible. Reversing the game executable is the most promising path.
Feb
19
comment Full Domain hash library
You can always chain a hash function with a stream cipher. Or simply use the hash in CTR mode for the expansion, similar to what Skein does internally.
Feb
19
revised What is the period of a cipher?
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Feb
19
revised What are the computational benefits of primes close to the power of 2?
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Feb
19
answered What are the computational benefits of primes close to the power of 2?
Feb
19
revised Can I jettison MAC if I already have SHA1(M)?
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Feb
19
revised Idea for secure password hash-likes, is this feasible/usable/workable?
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