poncho
Reputation
48,141
94/100 score
 Oct 1 comment Is it possible to add error propagation to OTP? @RichieFrame: nit, $GF(2^{8})$ multiplication wouldn't work, as a 0 in the pad would kill things. However, $GF(257)$ multiplication (with the convention that the 0x00 byte stands for the value 256) would work. Oct 1 comment Why does GnuPG save an array of remainders when generating prime numbers? @ZachDziura: the general formula is: if bit $i$ corresponds to the integer $ai+b$, then if $b % p = 0$, then set bits $kp$ (for integers $k$ in range), else if $a % p = 0$, then don't set any bits, else set bits $kp + p - (b a^{-1} \bmod p)$. Actually, if both $a % p = 0$ and $b % p = 0$, then no primes will be in range (as $ai + b$ will always be a multiple of $p$; presumably that'll never happen, as $a$ and $b$ must be relatively prime. Oct 1 comment Why does GnuPG save an array of remainders when generating prime numbers? @ZachDziura: actually, you would typically add twice the iteration (as there is little value even numbers. And, you don't divide each of the those numbers by each small prime (that's what you're trying to avoid); instead for each small prime $p$, you compute the initial candidate $prime % p$, and from that deduce which $prime+step$'s would be multiple of $p$. For example, if $p=3$ and $prime % p = 1$, then you know that $prime+2$, $prime+6$, $prime+10$, etc are multiples of 3; you can set those bits in the sieve Oct 1 answered Why does GnuPG save an array of remainders when generating prime numbers? Sep 30 awarded Enlightened Sep 30 awarded Nice Answer Sep 30 reviewed No Action Needed How can cryptographic signatures be somehow linked to a physical signature? Sep 30 reviewed No Action Needed Is it possbile to get same set of public and private keys twice while creating CSR ? If so where does the conflict happens !? Sep 30 reviewed No Action Needed Powerline password conversion Sep 30 comment Need some understanding on RSA public key exponent @ThomasPornin: yes, but you don't need to do it as a part of searching for the primes... Sep 29 answered Need some understanding on RSA public key exponent Sep 29 reviewed No Action Needed generate RSA public key having public modulus and exponent Sep 28 awarded Nice Answer Sep 27 awarded Enlightened Sep 27 awarded Nice Answer Sep 27 comment Is there specific name for simple XOR with ADD/SUB encoding? I suspect that malware authors use this as a method to avoid signature-based virus checkers. By cryptographical standards, this is a very weak method; however it may be sufficient to avoid simple-minded checks. Sep 26 awarded Enlightened Sep 26 awarded Nice Answer Sep 25 comment Is reverse NTRU still secure? @JeffreyQuesnelle: why would a digital signature system require a symmetric key exchange? Sep 25 answered Is reverse NTRU still secure?