5,491 reputation
1827
bio website
location
age
visits member for 2 years, 9 months
seen 3 hours ago

Aug
22
reviewed Close Variants of AES?
Aug
22
reviewed Leave Open Which causes longer “break” time (in general)?
Aug
22
comment Why does DES use exactly 16 rounds?
@fgrieu You are probably correct.
Aug
21
awarded  Custodian
Aug
12
comment Deterministic Rand function for Winternitz One Time Signatures
I need (at least) 256 bit outputs because the Winternitz OWF has a 256 bit output. I need (at least) a 256 bit key, because the risk of collisions in the leaf keys must nut exceed the risk of collisions in the message digest function. I need a 256 bit seed because the number of leafs is $2^{250}$ and the total number of independent leaf keys is $2^{256}$.
Aug
11
comment SHACAL in SHA-256
Yes, SHACAL-2 was e.g. selected as part of the NESSIE portfolio. However, it should be noted that some standard modes of operation don't have a 256-bit equivalent, such as GCM.
Aug
10
answered SHACAL in SHA-256
Aug
9
comment Discovering private exponent from public key
Correction: The order $q$ of $g$ is the least positive integer such that $1 = g^q \bmod N$. You are correct that an element $g$ is a generator of the multiplicative group if its order is $q = N-1$. Also please note that $N = 251$ isn't a safe prime, since $(N-1)/2 = 125$ isn't a prime.
Aug
9
comment Discovering private exponent from public key
The parameter $n$ in my answer is an arbitrary attack parameter that might be any value between $0$ and $128$.
Aug
9
comment Discovering private exponent from public key
@Joe In SRP, $g$ is supposed to be a generator of the multiplicative group, meaning that the order of $g$ should be $q = N-1$. Since $N$ is supposed to be a safe prime, the only other possible values are $q = (N-1)/2$, $q = 2$ and $q = 1$. Checking the order of $g$ is done by finding the least $q$ such that $g = g^q \bmod N$.
Aug
9
answered Discovering private exponent from public key
Aug
7
revised Interleaving bytes to make an effectively larger block size
deleted 2 characters in body
Aug
7
comment Interleaving bytes to make an effectively larger block size
If by "interleaving" you mean transposing, please see the second case in my answer. Your function has approximately the same collision rate as CBC mode or CFB mode under CPA, but at the expense of three AES invocations per 128 bits, instead of just one.
Aug
6
revised Interleaving bytes to make an effectively larger block size
added 907 characters in body
Aug
5
revised Interleaving bytes to make an effectively larger block size
deleted 237 characters in body
Aug
5
revised Interleaving bytes to make an effectively larger block size
added 965 characters in body
Aug
5
revised Interleaving bytes to make an effectively larger block size
added 8 characters in body
Aug
5
revised Interleaving bytes to make an effectively larger block size
added 550 characters in body
Aug
5
answered Interleaving bytes to make an effectively larger block size
Aug
3
comment Cryptographically Secure Hash Algorithm with Very Specific Property
1. What exactly do the operators $\oplus$ and $+$ signify? Bitwise xor and string concatenation, or something else? 2. Are the $K_i$ values supposed to be of a fixed bit length, or do you want the relation to hold for inputs of any length?