10,512 reputation
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bio website github.com/CodesInChaos
location Frankfurt, Germany
age
visits member for 3 years, 6 months
seen 8 hours ago

Aug
26
comment How is block cipher padding verified for consistancy?
Depends on the padding in question, and on how the validation routine works. But should be around 1/256 resulting in a message that has length (blocksize-1) mod blocksize.
Aug
26
suggested approved edit on malleability tag wiki excerpt
Aug
26
reviewed Approve malleability tag wiki excerpt
Aug
26
comment What is the post-quantum cryptography alternative to Diffie-Hellman?
Could you explain how to do key agreement once you have authentication?
Aug
26
comment How is CipherCloud doing homomorphic encryption?
My impression is that they don't use order preserving encryption everywhere, and in the case of names they simply split it in parts, which wouldn't allow prefix-matches. But the available information is so sparse that it's hard to say anything concrete.
Aug
26
reviewed Approve Are Stream Ciphers Less Secure?
Aug
26
comment Several questions about Paillier cryptosystem
@Thomas In this context it wasn't a bump, it was an edit. Probably an edit by an unregistered user.
Aug
25
comment Is there a way to make RC4 (ARCFOUR) secure, or is it completely broken?
The temptation of homebrew crypto is certainly strong. It's one of the points where I often disregard my own advice.
Aug
25
comment Is there a way to make RC4 (ARCFOUR) secure, or is it completely broken?
@AndrewSmith That article only talks about weaknesses in RC4, not weaknesses in general streamciphers. You make it sound like stream-ciphers in general are weaker than block-ciphers. They're less flexible, but not weaker when used correctly.
Aug
25
answered How is CipherCloud doing homomorphic encryption?
Aug
25
revised How is CipherCloud doing homomorphic encryption?
deleted 2 characters in body
Aug
25
revised Is there a way to make RC4 (ARCFOUR) secure, or is it completely broken?
added 238 characters in body; added 204 characters in body
Aug
25
comment Is there a way to make RC4 (ARCFOUR) secure, or is it completely broken?
@Kevin Could you talk a bit more about what you're trying to achieve, where your keys come from, what your threat model is,... ?
Aug
25
revised Is there a way to make RC4 (ARCFOUR) secure, or is it completely broken?
edited tags
Aug
25
answered Is there a way to make RC4 (ARCFOUR) secure, or is it completely broken?
Aug
25
comment Is there a way to make RC4 (ARCFOUR) secure, or is it completely broken?
@AndrewSmith There is no reason to consider stream ciphers intrinsically weak. They require nonces(IV must not be reused) and they're malleable. But when used correctly they're perfectly fine. You can even turn a block cipher into a stream cipher by using CTR mode.
Aug
25
comment Is it possible to pick your Ed25519 public key?
Can you fix the division part? The rest of the answer contains a nice explanation why the attacker doesn't care about k, but making it sound like DL is easy is highly misleading.
Aug
24
revised HRNG for One Time Pad
added 59 characters in body
Aug
24
answered How to submit a new method of encryption?
Aug
24
comment How do ciphers change plaintext into numeric digits for computing?
In practice you don't use the symmetric key as m. You add specialized padding.