207 reputation
18
bio website isplab.tudelft.nl/users/…
location Delft, Netherlands
age 27
visits member for 1 year, 1 month
seen Jun 5 at 12:24
stats profile views 4

Scientific programmer at TU Delft


May
14
asked DGK Cryptosystem Encryption Speedup
May
9
comment Chinese Remainder Theorem and RSA
Thank you very much. I can see that your knowledge of this subject is really good, but I am looking in 2 distinct books at the formulation of the CRT and I am failing to see how this simple statement that you presented above derives from it. The CRT states that a solution for a system of r linear congruences exists and is unique modulo n, where $n = \prod_{i=0}^rn_i$, but how do you use this? The "General Case" on Wikipedia doesn't help: en.wikipedia.org/wiki/Chinese_remainder_theorem#General_case
May
9
awarded  Supporter
May
9
accepted Chinese Remainder Theorem and RSA
May
9
comment Chinese Remainder Theorem and RSA
That's a really nice and detailed proof, but I need more help to understand it: First, how did you end up with this formula: $M_1 = (M^d \bmod N) \bmod p = ((M \bmod p)^{d \mod p-1}) \bmod p$? Could you please detail it? I don't understand how you applied Fermat's "Little" Theorem to obtain it. It's clear how you've proven the formulae for the recombination step, but I'm not able to understand how does the CRT work in this case. How do you "immediately deduce that" $m = (M^d \bmod N) \mod pq$?
May
9
comment Chinese Remainder Theorem and RSA
@Ninefingers: Yes, I know, it's just that comments don't show previews and, anyway, I'll try to use it next time. Thanks.
May
9
revised Chinese Remainder Theorem and RSA
added 15 characters in body
May
9
comment Chinese Remainder Theorem and RSA
It's not clear to me how the CRT is applied to derive this formula: m = m_2 + (h * q), where h = q_inv * (m_1 - m_2) (mod p). I would really appreciate it if you could detail this procedure.
May
9
awarded  Editor
May
9
revised Chinese Remainder Theorem and RSA
added 105 characters in body
May
9
comment Chinese Remainder Theorem and RSA
@mikeazo: The security update is not relevant for this conversation at the moment. If I manage to understand the way the CRT is applied for RSA, then I should be able to figure the rest out by myself, because it is similar. Please ignore my reference to DGK for now.
May
9
asked Chinese Remainder Theorem and RSA
May
4
awarded  Student
May
3
awarded  Scholar
May
3
awarded  Analytical
May
3
accepted Generating Random Primes
May
3
comment Generating Random Primes
Now this is a really good answer. Thanks for taking the time to provide such a detailed explanation. It really clarifies the issue. I will probably go with the heuristic method, since it saves me some headache. There shouldn't be any performance concern at the moment, since prime numbers are required only for key generation, which I don't have to perform many times.
May
3
asked Generating Random Primes
Apr
24
awarded  Autobiographer