keygen.c

很有意思得加密解密算法

/* KEYGEN.C - strong RSA key-pair generation for RSAREF
 */

#include "global.h"
#include "rsaref.h"
#include "nn.h"
#include "rsaprime.h"
#include <stdio.h>
#include <time.h>
#include <stdlib.h>


/* Generates an strong RSA key pair with a given length and public exponent.
 */

const char *printMsg[11] =    {"\nGenerating tp...\0",
                               "Done.\nGenerating rp...\0",
                               "Done.\nGenerating sp...\0",
                               "Done.\nGenerating p...\0",
                               "Done.\nFinish generating p.\0",
                               "\nGenerating tq...\0",
                               "Done.\nGenerating rq...\0",
                               "Done.\nGenerating sq...\0",
                               "Done.\nGenerating q...\0",
                               "Done.\nFinish generating q.\0","\0"};

int R_GenerateStrongKeys (publicKey, privateKey, protoKey)
R_RSA_PUBLIC_KEY *publicKey;                          /* new RSA public key */
R_RSA_PRIVATE_KEY *privateKey;                       /* new RSA private key */
R_RSA_PROTO_KEY *protoKey;                             /* RSA prototype key */
{
  NN_DIGIT d[MAX_NN_DIGITS], dP[MAX_NN_DIGITS], dQ[MAX_NN_DIGITS],
    e[MAX_NN_DIGITS], n[MAX_NN_DIGITS], p[MAX_NN_DIGITS], phiN[MAX_NN_DIGITS],
    pMinus1[MAX_NN_DIGITS], q[MAX_NN_DIGITS], qInv[MAX_NN_DIGITS],
    qMinus1[MAX_NN_DIGITS], t[MAX_NN_DIGITS];
  int status;
  unsigned int nDigits, pDigits;

  if ((protoKey->bits < MIN_RSA_MODULUS_BITS) ||
      (protoKey->bits > MAX_RSA_MODULUS_BITS))
    return (RE_MODULUS_LEN);
  nDigits = (protoKey->bits + NN_DIGIT_BITS - 1) / NN_DIGIT_BITS;
  pDigits = (nDigits + 1) / 2;

  /* Generate random RSA primes p and q so that product has correct length.
   */

  /* NOTE: for 65537, this assumes NN_DIGIT is at least 17 bits. */
  NN_ASSIGN_DIGIT
    (e, protoKey->useFermat4 ? (NN_DIGIT)65537 : (NN_DIGIT)3, nDigits);
  FindStrongRSAPrime (p, (protoKey->bits + 1) / 2, e, &printMsg[0]);
  FindStrongRSAPrime (q, (protoKey->bits / 2) + 1, e, &printMsg[5]);

  /* Sort so that p > q. (p = q case is extremely unlikely.)
   */
  if (NN_Cmp (p, q, pDigits) < 0) {
    NN_Assign (t, p, pDigits);
    NN_Assign (p, q, pDigits);
    NN_Assign (q, t, pDigits);
  }

  /* Compute n = pq, qInv = q^{-1} mod p, d = e^{-1} mod (p-1)(q-1),
     dP = d mod p-1, dQ = d mod q-1.
   */
  NN_Mult (n, p, q, pDigits);
  NN_ModInv (qInv, q, p, pDigits);

  NN_ASSIGN_DIGIT (t, 1, pDigits);
  NN_Sub (pMinus1, p, t, pDigits);
  NN_Sub (qMinus1, q, t, pDigits);
  NN_Mult (phiN, pMinus1, qMinus1, pDigits);

  NN_ModInv (d, e, phiN, nDigits);
  NN_Mod (dP, d, nDigits, pMinus1, pDigits);
  NN_Mod (dQ, d, nDigits, qMinus1, pDigits);

  publicKey->bits = privateKey->bits = protoKey->bits;
  NN_Encode (publicKey->modulus, MAX_RSA_MODULUS_LEN, n, nDigits);
  NN_Encode (publicKey->exponent, MAX_RSA_MODULUS_LEN, e, 1);
  R_memcpy
    ((POINTER)privateKey->modulus, (POINTER)publicKey->modulus,
     MAX_RSA_MODULUS_LEN);
  R_memcpy
    ((POINTER)privateKey->publicExponent, (POINTER)publicKey->exponent,
     MAX_RSA_MODULUS_LEN);
  NN_Encode (privateKey->exponent, MAX_RSA_MODULUS_LEN, d, nDigits);
  NN_Encode (privateKey->prime[0], MAX_RSA_PRIME_LEN, p, pDigits);
  NN_Encode (privateKey->prime[1], MAX_RSA_PRIME_LEN, q, pDigits);
  NN_Encode (privateKey->primeExponent[0], MAX_RSA_PRIME_LEN, dP, pDigits);
  NN_Encode (privateKey->primeExponent[1], MAX_RSA_PRIME_LEN, dQ, pDigits);
  NN_Encode (privateKey->coefficient, MAX_RSA_PRIME_LEN, qInv, pDigits);

  /* Zeroize sensitive information.
   */
  R_memset ((POINTER)d, 0, sizeof (d));
  R_memset ((POINTER)dP, 0, sizeof (dP));
  R_memset ((POINTER)dQ, 0, sizeof (dQ));
  R_memset ((POINTER)p, 0, sizeof (p));
  R_memset ((POINTER)phiN, 0, sizeof (phiN));
  R_memset ((POINTER)pMinus1, 0, sizeof (pMinus1));
  R_memset ((POINTER)q, 0, sizeof (q));
  R_memset ((POINTER)qInv, 0, sizeof (qInv));
  R_memset ((POINTER)qMinus1, 0, sizeof (qMinus1));
  R_memset ((POINTER)t, 0, sizeof (t));
  
  return (0);
}