5,446 reputation
1726
bio website
location
age
visits member for 2 years, 8 months
seen 1 hour ago

Feb
10
comment How can I simulate and measure brute force hacking using RSA?
160 bits sound about right if by "brute force" one means literally iterating through all odd numbers from $\sqrt(N)$ and checking if the value divides $N$.
Feb
8
awarded  Yearling
Feb
5
answered Do both client and server need to implement OpenSSL protections to protect from CBC attacks
Feb
4
awarded  Nice Question
Feb
3
comment Can passwords be stored securely so that a similarity comparison can be made?
No, it would just require storing $h = Hash(f(PW))$. If $PW_0$ and $PW_1$ are similar, then $h_0 = h_1$.
Feb
3
comment Can passwords be stored securely so that a similarity comparison can be made?
One answer would be that the entered passwords are always passed through a function $f$ such that $f(PW_0) = f(PW_1)$ iff the passwords are "similar". One trivial example would be converting all entered passwords to all lower case before further processing.
Feb
2
comment What is difference between PRG, PRF, and PRP
It would be a stretch, so not quite. A PRF has to be indistinguishable from a random function. A PRP might be, but doesn't have to be, a PRF in this sense. However, the security proof for e.g. CTR mode is based on the premise that the block cipher (a PRP) might be modeled as a PRF, as long as the key stream is constrained to the square root of the cardinality of the total set of possible blocks.
Feb
2
comment Proof for exponentiation in modular arithemtic
This is a proof by induction. We know it is true for $e = 1$. Using the formula in the answer, we can then prove it is true for $e = 2$ as well, and then for $e = 3$ etc. No matter how large $e$ gets, we might prove that the formula is true for $e + 1$ as well. Hence, by induction, it is true for all integer values of $e$.
Feb
2
comment What is difference between PRG, PRF, and PRP
The difference between a PRF and a PRP is that the PRP is a bijective function and the PRF is not. There are no other differences, but of course this difference has various implications for their respective applications.
Feb
2
answered Why is CBC based on AES malleable in blocks other than the first block?
Jan
30
revised Hardness of finding mutual discrete logarithms of small generators in $\mathbb{Z}_p$
added 3 characters in body
Jan
30
revised Hardness of finding mutual discrete logarithms of small generators in $\mathbb{Z}_p$
added 240 characters in body
Jan
30
revised Hardness of finding mutual discrete logarithms of small generators in $\mathbb{Z}_p$
added 418 characters in body
Jan
29
revised Hardness of finding mutual discrete logarithms of small generators in $\mathbb{Z}_p$
added 136 characters in body
Jan
29
revised Hardness of finding mutual discrete logarithms of small generators in $\mathbb{Z}_p$
added 350 characters in body
Jan
28
comment Secret sharing - no dealer, modifiable, verifiable
If robustness isn't a requirement, also look at Pedersen's original scheme link.springer.com/chapter/10.1007%2F3-540-46416-6_47
Jan
28
comment Secret sharing - no dealer, modifiable, verifiable
This sounds a lot like the Joint-Uncond-Secure-RSS scheme of link.springer.com/chapter/10.1007%2F3-540-68339-9_31. The trick is to let each participant be a dealer, or, put differently, build the scheme around participants who generate their shares randomly.
Jan
28
asked Hardness of finding mutual discrete logarithms of small generators in $\mathbb{Z}_p$
Jan
27
comment How can I find the prime numbers used in RSA?
The approach is just basic algebra. If the factors are close to the floor $x$ of the square root, the equation $r + (x-p)(q-x) - x(q+p-2x)$ will be dominated by the first and third term and the second factor of the third term will consequently be a function of the magnitude of $r$.
Jan
27
comment How cryptographically secure was the original WW2 Enigma machine, from a modern viewpoint?
AES is believed to be (IND-CPA) secure even if the plain text is chosen by the attacker, so why do you include the restriction of no operator errors?