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Nov
7
reviewed No Action Needed Available programs that can verify the working of a simple substitution cipher
Nov
7
reviewed No Action Needed Proving that a function is not invert-able (one way function)
Nov
7
reviewed Reviewed Repeated XOR decryption
Nov
7
reviewed No Action Needed Franklin-Reiter related message attack m2 = a(m1)+b
Nov
7
comment Is it possible to decrypt the entire message with one half of the key in this example?
@user4131185: you are correct; knowledge of one half of the key does not allow the attacker to deduce anything, as long as you use the key only once. If you encrypt, say, two 256 bit blocks, then knowledge of the half key does leak information about the blocks. As for the second issue, well, if it is not important that someone with the keys to decrypt the data, well, I would suggest a more secure way would be to output a constant block of all 0's; a constant block of 0's cannot leak anything about the plaintext, and hence is more secure.
Nov
6
revised Is it possible to decrypt the entire message with one half of the key in this example?
added 1 character in body
Nov
6
answered Is it possible to decrypt the entire message with one half of the key in this example?
Nov
6
comment Is it possible to add OpenSSL engine for a block algorithm with different input and output block size?
What sort of mode would you be running your 'not-precisely-a-block-cipher' in? Normal CBC mode won't work. Also, is the algorithm deterministic or randomized? If it's randomized, then things like CTR mode are off the table. Thirdly, is there any particular reason you think that your cipher is actually secure?
Nov
6
awarded  Nice Answer
Nov
6
awarded  Nice Answer
Nov
5
reviewed No Action Needed Is a die implemented in a physics engine truly random?
Nov
5
reviewed No Action Needed In RSA, why does Alice's $N$ need to be relatively prime to Bob's $N$?
Nov
5
reviewed Close The use of the term “sound” in cryptography
Nov
5
reviewed No Action Needed Is a die implemented in a physics engine truly random?
Nov
5
reviewed No Action Needed What is more secure, a ciphertext encrypted with AES-256 or encrypted with 3 different AES-128 keys?
Nov
5
reviewed No Action Needed Is a die implemented in a physics engine truly random?
Nov
4
reviewed Approve Is python a secure programming language for cryptography?
Nov
4
revised Is SEAL 3.0 broken?
added 400 characters in body
Nov
4
answered Is SEAL 3.0 broken?
Nov
3
comment Is $(f(X), G(X))$ pseudorandom?
Hint: can you think of a pair $f$, $G$ where it is distinguishable?