src/RsaStd.cpp

   1 #include "RsaStd.h"
   2
   3 #include <iostream>
   4 using namespace std;
   5
   6 #include "Rand.h"
   7 #include "Utils.h"
   8
   9 pair<Rsa::KeyPub, RsaStd::KeyPriv> RsaStd::generateRSAKeys(uint exponent, uint keySizeBits)
  10 {
  11    mpz_class p, q, phi;
  12    Rsa::KeyPub kPub;
  13    KeyPriv kPriv;
  14
  15    do
  16    {
  17       kPub.e = exponent;
  18       p = Rand::randPrime(keySizeBits / 2);
  19       q = Rand::randPrime(keySizeBits / 2);
  20
  21       kPriv.n = kPub.n = p * q;
  22       phi = (p - 1) * (q - 1);
  23
  24    // d = e^-1 (mode phi).
  25    } while (mpz_invert(kPriv.d.get_mpz_t(), kPub.e.get_mpz_t(), phi.get_mpz_t()) == 0); // If 'd' is not invertible we try another primes.
  26
  27    return make_pair(kPub, kPriv);
  28 }
  29
  30 mpz_class RsaStd::sign(const mpz_class& m, const KeyPriv& kPriv)
  31 {
  32    mpz_class result;
  33
  34    // m^d (mod n).
  35    mpz_powm_sec(result.get_mpz_t(), m.get_mpz_t(), kPriv.d.get_mpz_t(), kPriv.n.get_mpz_t());
  36    return result;
  37 }