9,467 reputation
12346
bio website github.com/CodesInChaos
location Frankfurt, Germany
age
visits member for 3 years
seen 4 hours ago

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.
Aug
24
comment Detect tampering of data
As a side-note: A plain md5 hash is not suitable for password hashing. Use an appropriate function, such as scrypt, bcrypt or PBKDF2.
Aug
23
comment Can I make a cipher (ex: Vigenère) harder to break?
For a substitution cipher it's easy: Use a 128 bit block instead of a 4.7 bit one.
Aug
23
comment Can I make a cipher (ex: Vigenère) harder to break?
You could compress the data before encrypting it. But why do you want to use classic ciphers?
Aug
23
answered HRNG for One Time Pad
Aug
23
reviewed Approve suggested edit on Why is padding used for RSA encryption given that it is not a block cipher?
Aug
23
answered Why is padding used for RSA encryption given that it is not a block cipher?
Aug
23
comment Is it possible to pick your Ed25519 public key?
You can ignore the hashing step, it doesn't affect security. An attacker wins if he finds $a$, he doesn't care about finding a $k$.
Aug
23
answered Is it possible to pick your Ed25519 public key?