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1h
comment SSL-like protocol with public-key hard-coded in the client
hardcode a 2nd revocation key into the client?
3h
comment Does AES-128 have the same strength as AES-256 with a padded key?
We can both agree that 14 rounds is better than 10, but the 256-bit key schedule is weaker. AES-256 with a 128-bit key is weaker than AES-128 extended to 14 rounds, the question is how much weaker. Do related key attacks now apply? Can the subkey alignment allow new attacks? What about non public attacks?
18h
comment Positioning of keys in encrypted text
The name of this technique is obfuscation
18h
comment Does AES-128 have the same strength as AES-256 with a padded key?
And yes, padding that is non 0 has the same problems
18h
answered Does AES-128 have the same strength as AES-256 with a padded key?
1d
comment How to understand authenticator working process
You may want to reword that in better english
Apr
11
comment Difference between plain AES CTR and “CCM-style” CTR
Technically, a correct CTR implementation would have bounds checking for the size of the input block that is not populated by the nonce, or force the nonce to be 96 bits and only increment the remaining uInt32. We all know how many problems incorrect bounds checking can cause...
Apr
10
comment cryptography and use of python programming language
I have never heard this
Apr
9
comment Security of this deterministic encryption scheme
No, but this is a scheme that is more than just the mode; I assume the plaintext MAC is sufficient to authenticate, but it is truncated possibly past a desired security level
Apr
9
comment Security of this deterministic encryption scheme
There is also no MAC on the ciphertext
Apr
9
comment Will repeated rounds of SHA-512 provide random numbers?
pseudorandom yes, depending on your use of the outputs, the method you described may be a massive security risk
Apr
9
comment SHA256-based stream cipher
unbreakable up to max 128-bit security level, possibly less in practice depending on generation method of ECC private keys, and as mentioned already, vulnerable to known plaintext type attacks
Apr
8
comment IV = Filename XOR CipherKey?
[ Hash(GUID), truncate to blocksize, encrypt ] = IV
Apr
8
comment IV = Filename XOR CipherKey?
XOR is fine if done correctly. With CBC, the IV is ok to be known, but should be unpredictable, and creating it from fixed data makes it predictable. Using the key as that fixed data may be ok if you are encrypting a counter to gen the IV. And by encrypting I mean using the block cipher, not xor
Apr
8
comment Multi cipher CTR
Based on your explanation, breaking one cipher would break 1/3 of the ciphertext
Apr
8
comment Convert SpookyHash to semi-secure 192bit hash
average funded = some kid at a computer with a botnet of a few thousand computers that he can send commands to, well funded = a petaflop supercomputer in the basement.
Apr
8
comment Convert SpookyHash to semi-secure 192bit hash
1 GPU*year = a few minutes for a well funded attacker, and a few seconds for a nation state.
Apr
8
comment What benefit is there to using AES over my custom cipher for secure storage?
That sounds like a homework question, and a poorly worded one at that. The title of the question also does not match.
Apr
8
comment Multi cipher CTR
Yes.. incrementing the IV for the same block output is unnecessary with different keys
Apr
8
comment Multi cipher CTR
I understand what you want to know, but you have not explained how the operation actually works with enough detail for the question to be answered