/* R_KEYGEN.C - key-pair generation for RSAREF *//* Copyright (C) RSA Laboratories, a division of RSA Data Security,     Inc., created 1991. All rights reserved. */#include "global.h"#include "rsaref.h"#include "r_random.h"#include "nn.h"#include "prime.h"static int RSAFilter PROTO_LIST  ((NN_DIGIT *, unsigned int, NN_DIGIT *, unsigned int));static int RelativelyPrime PROTO_LIST  ((NN_DIGIT *, unsigned int, NN_DIGIT *, unsigned int));/* Generates an RSA key pair with a given length and public exponent. */int R_GeneratePEMKeys (publicKey, privateKey, protoKey, randomStruct)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 */R_RANDOM_STRUCT *randomStruct;                          /* random structure */{  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], u[MAX_NN_DIGITS],    v[MAX_NN_DIGITS];  int status;  unsigned int nDigits, pBits, pDigits, qBits;    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;  pBits = (protoKey->bits + 1) / 2;  qBits = protoKey->bits - pBits;  /* 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);  /* Generate prime p between 3*2^(pBits-2) and 2^pBits-1, searching       in steps of 2, until one satisfies gcd (p-1, e) = 1.   */  NN_Assign2Exp (t, pBits-1, pDigits);  NN_Assign2Exp (u, pBits-2, pDigits);  NN_Add (t, t, u, pDigits);  NN_ASSIGN_DIGIT (v, 1, pDigits);  NN_Sub (v, t, v, pDigits);  NN_Add (u, u, v, pDigits);  NN_ASSIGN_DIGIT (v, 2, pDigits);  do {    if (status = GeneratePrime (p, t, u, v, pDigits, randomStruct))      return (status);  }  while (! RSAFilter (p, pDigits, e, 1));    /* Generate prime q between 3*2^(qBits-2) and 2^qBits-1, searching       in steps of 2, until one satisfies gcd (q-1, e) = 1.   */  NN_Assign2Exp (t, qBits-1, pDigits);  NN_Assign2Exp (u, qBits-2, pDigits);  NN_Add (t, t, u, pDigits);  NN_ASSIGN_DIGIT (v, 1, pDigits);  NN_Sub (v, t, v, pDigits);  NN_Add (u, u, v, pDigits);  NN_ASSIGN_DIGIT (v, 2, pDigits);  do {    if (status = GeneratePrime (q, t, u, v, pDigits, randomStruct))      return (status);  }  while (! RSAFilter (q, pDigits, e, 1));    /* 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);}/* Returns nonzero iff GCD (a-1, b) = 1.   Lengths: a[aDigits], b[bDigits].   Assumes aDigits < MAX_NN_DIGITS, bDigits < MAX_NN_DIGITS. */static int RSAFilter (a, aDigits, b, bDigits)NN_DIGIT *a, *b;unsigned int aDigits, bDigits;{  int status;  NN_DIGIT aMinus1[MAX_NN_DIGITS], t[MAX_NN_DIGITS];    NN_ASSIGN_DIGIT (t, 1, aDigits);  NN_Sub (aMinus1, a, t, aDigits);    status = RelativelyPrime (aMinus1, aDigits, b, bDigits);  /* Zeroize sensitive information.   */  R_memset ((POINTER)aMinus1, 0, sizeof (aMinus1));    return (status);}/* Returns nonzero iff a and b are relatively prime.   Lengths: a[aDigits], b[bDigits].   Assumes aDigits >= bDigits, aDigits < MAX_NN_DIGITS. */static int RelativelyPrime (a, aDigits, b, bDigits)NN_DIGIT *a, *b;unsigned int aDigits, bDigits;{  int status;  NN_DIGIT t[MAX_NN_DIGITS], u[MAX_NN_DIGITS];    NN_AssignZero (t, aDigits);  NN_Assign (t, b, bDigits);  NN_Gcd (t, a, t, aDigits);  NN_ASSIGN_DIGIT (u, 1, aDigits);  status = NN_EQUAL (t, u, aDigits);    /* Zeroize sensitive information.   */  R_memset ((POINTER)t, 0, sizeof (t));    return (status);}