+++ /dev/null
-/*
- * Copyright (c) 1997-1999 The Stanford SRP Authentication Project
- * All Rights Reserved.
- *
- * Permission is hereby granted, free of charge, to any person obtaining
- * a copy of this software and associated documentation files (the
- * "Software"), to deal in the Software without restriction, including
- * without limitation the rights to use, copy, modify, merge, publish,
- * distribute, sublicense, and/or sell copies of the Software, and to
- * permit persons to whom the Software is furnished to do so, subject to
- * the following conditions:
- *
- * The above copyright notice and this permission notice shall be
- * included in all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
- * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
- * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
- *
- * IN NO EVENT SHALL STANFORD BE LIABLE FOR ANY SPECIAL, INCIDENTAL,
- * INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND, OR ANY DAMAGES WHATSOEVER
- * RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER OR NOT ADVISED OF
- * THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF LIABILITY, ARISING OUT
- * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
- *
- * In addition, the following conditions apply:
- *
- * 1. Any software that incorporates the SRP authentication technology
- * must display the following acknowlegment:
- * "This product uses the 'Secure Remote Password' cryptographic
- * authentication system developed by Tom Wu (tjw@CS.Stanford.EDU)."
- *
- * 2. Any software that incorporates all or part of the SRP distribution
- * itself must also display the following acknowledgment:
- * "This product includes software developed by Tom Wu and Eugene
- * Jhong for the SRP Distribution (http://srp.stanford.edu/srp/)."
- *
- * 3. Redistributions in source or binary form must retain an intact copy
- * of this copyright notice and list of conditions.
- */
-
-#include <stdio.h>
-
-#include "t_defines.h"
-#include "t_pwd.h"
-#include "t_read.h"
-#include "bn.h"
-#include "bn_lcl.h"
-#include "bn_prime.h"
-
-#define TABLE_SIZE 32
-
-static int witness(BIGNUM *w, const BIGNUM *a, const BIGNUM *a1,
- const BIGNUM *a1_odd, int k, BN_CTX *ctx, BN_MONT_CTX *mont);
-
-/*
- * This is the safe prime generation logic.
- * To generate a safe prime p (where p = 2q+1 and q is prime), we start
- * with a random odd q that is one bit shorter than the desired length
- * of p. We use a simple 30-element sieve to filter the values of q
- * and consider only those that are 11, 23, or 29 (mod 30). (If q were
- * anything else, either q or p would be divisible by 2, 3, or 5).
- * For the values of q that are left, we apply the following tests in
- * this order:
- *
- * trial divide q
- * let p = 2q + 1
- * trial divide p
- * apply Fermat test to q (2^q == 2 (mod q))
- * apply Fermat test to p (2^p == 2 (mod p))
- * apply real probablistic primality test to q
- * apply real probablistic primality test to p
- *
- * A number that passes all these tests is considered a safe prime for
- * our purposes. The tests are ordered this way for efficiency; the
- * slower tests are run rarely if ever at all.
- */
-
-static int
-trialdiv(x)
- const BigInteger x;
-{
- static int primes[] = { /* All odd primes < 256 */
- 3, 5, 7, 11, 13, 17, 19, 23, 29,
- 31, 37, 41, 43, 47, 53, 59, 61, 67,
- 71, 73, 79, 83, 89, 97, 101, 103,
- 107, 109, 113, 127, 131, 137, 139, 149, 151,
- 157, 163, 167, 173, 179, 181, 191, 193, 197,
- 199, 211, 223, 227, 229, 233, 239, 241, 251
- };
- static int nprimes = sizeof(primes) / sizeof(int);
- int i;
-
- for(i = 0; i < nprimes; ++i) {
- if(BigIntegerModInt(x, primes[i]) == 0)
- return primes[i];
- }
- return 1;
-}
-
-/* x + sieve30[x%30] == 11, 23, or 29 (mod 30) */
-
-static int sieve30[] =
-{ 11, 10, 9, 8, 7, 6, 5, 4, 3, 2,
- 1, 12, 11, 10, 9, 8, 7, 6, 5, 4,
- 3, 2, 1, 6, 5, 4, 3, 2, 1, 12
-};
-
-/* Find a Sophie-Germain prime between "lo" and "hi". NOTE: this is not
- a "safe prime", but the smaller prime. Take 2q+1 to get the safe prime. */
-
-static void
-sophie_germain(q, lo, hi)
- BigInteger q; /* assumed initialized */
- const BigInteger lo;
- const BigInteger hi;
-{
- BigInteger m, p, r;
- char parambuf[MAXPARAMLEN];
- int foundprime = 0;
- int i, mod30;
-
- m = BigIntegerFromInt(0);
- BigIntegerSub(m, hi, lo);
- i = (BigIntegerBitLen(m) + 7) / 8;
- t_random(parambuf, i);
- r = BigIntegerFromBytes(parambuf, i);
- BigIntegerMod(r, r, m);
-
- BigIntegerAdd(q, r, lo);
- if(BigIntegerModInt(q, 2) == 0)
- BigIntegerAddInt(q, q, 1); /* make q odd */
-
- mod30 = BigIntegerModInt(q, 30); /* mod30 = q % 30 */
-
- BigIntegerFree(m);
- m = BigIntegerFromInt(2); /* m = 2 */
- p = BigIntegerFromInt(0);
-
- while(BigIntegerCmp(q, hi) < 0) {
- if(trialdiv(q) < 2) {
- BigIntegerMulInt(p, q, 2); /* p = 2 * q */
- BigIntegerAddInt(p, p, 1); /* p += 1 */
- if(trialdiv(p) < 2) {
- BigIntegerModExp(r, m, q, q); /* r = 2^q % q */
- if(BigIntegerCmpInt(r, 2) == 0) { /* if(r == 2) */
- BigIntegerModExp(r, m, p, p); /* r = 2^p % p */
- if(BigIntegerCmpInt(r, 2) == 0) { /* if(r == 2) */
- if(BigIntegerCheckPrime(q) && BigIntegerCheckPrime(p)) {
- ++foundprime;
- break;
- }
- }
- }
- }
- }
-
- i = sieve30[mod30];
- BigIntegerAddInt(q, q, i); /* q += i */
- mod30 = (mod30 + i) % 30;
- }
-
- /* should wrap around on failure */
- if(!foundprime) {
- fprintf(stderr, "Prime generation failed!\n");
- exit(1);
- }
-
- BigIntegerFree(r);
- BigIntegerFree(m);
- BigIntegerFree(p);
-}
-
-_TYPE( struct t_confent * )
-t_makeconfent(tc, nsize)
- struct t_conf * tc;
- int nsize;
-{
- BigInteger n, g, q, t, u;
-
- t = BigIntegerFromInt(0);
- u = BigIntegerFromInt(1); /* u = 1 */
- BigIntegerLShift(t, u, nsize - 2); /* t = 2^(nsize-2) */
- BigIntegerMulInt(u, t, 2); /* u = 2^(nsize-1) */
-
- q = BigIntegerFromInt(0);
- sophie_germain(q, t, u);
-
- n = BigIntegerFromInt(0);
- BigIntegerMulInt(n, q, 2);
- BigIntegerAddInt(n, n, 1);
-
- /* Look for a generator mod n */
- g = BigIntegerFromInt(2);
- while(1) {
- BigIntegerModExp(t, g, q, n); /* t = g^q % n */
- if(BigIntegerCmpInt(t, 1) == 0) /* if(t == 1) */
- BigIntegerAddInt(g, g, 1); /* ++g */
- else
- break;
- }
- BigIntegerFree(t);
- BigIntegerFree(u);
- BigIntegerFree(q);
-
- tc->tcbuf.modulus.data = tc->modbuf;
- tc->tcbuf.modulus.len = BigIntegerToBytes(n, tc->tcbuf.modulus.data);
- BigIntegerFree(n);
-
- tc->tcbuf.generator.data = tc->genbuf;
- tc->tcbuf.generator.len = BigIntegerToBytes(g, tc->tcbuf.generator.data);
- BigIntegerFree(g);
-
- tc->tcbuf.index = 1;
- return &tc->tcbuf;
-}
-
-_TYPE( struct t_confent * )
-t_makeconfent_c(tc, nsize)
- struct t_conf * tc;
- int nsize;
-{
- BigInteger g, n, p, q, j, k, t, u;
- int psize, qsize;
-
- psize = nsize / 2;
- qsize = nsize - psize;
-
- t = BigIntegerFromInt(1); /* t = 1 */
- u = BigIntegerFromInt(0);
- BigIntegerLShift(u, t, psize - 3); /* u = t*2^(psize-3) = 2^(psize-3) */
- BigIntegerMulInt(t, u, 3); /* t = 3*u = 1.5*2^(psize-2) */
- BigIntegerAdd(u, u, t); /* u += t [u = 2^(psize-1)] */
- j = BigIntegerFromInt(0);
- sophie_germain(j, t, u);
-
- k = BigIntegerFromInt(0);
- if(qsize != psize) {
- BigIntegerFree(t);
- t = BigIntegerFromInt(1); /* t = 1 */
- BigIntegerLShift(u, t, qsize - 3); /* u = t*2^(qsize-3) = 2^(qsize-3) */
- BigIntegerMulInt(t, u, 3); /* t = 3*u = 1.5*2^(qsize-2) */
- BigIntegerAdd(u, u, t); /* u += t [u = 2^(qsize-1)] */
- }
- sophie_germain(k, t, u);
-
- p = BigIntegerFromInt(0);
- BigIntegerMulInt(p, j, 2); /* p = 2 * j */
- BigIntegerAddInt(p, p, 1); /* p += 1 */
-
- q = BigIntegerFromInt(0);
- BigIntegerMulInt(q, k, 2); /* q = 2 * k */
- BigIntegerAddInt(q, q, 1); /* q += 1 */
-
- n = BigIntegerFromInt(0);
- BigIntegerMul(n, p, q); /* n = p * q */
- BigIntegerMul(u, j, k); /* u = j * k */
-
- BigIntegerFree(p);
- BigIntegerFree(q);
- BigIntegerFree(j);
- BigIntegerFree(k);
-
- g = BigIntegerFromInt(2); /* g = 2 */
-
- /* Look for a generator mod n */
- while(1) {
- BigIntegerModExp(t, g, u, n); /* t = g^u % n */
- if(BigIntegerCmpInt(t, 1) == 0)
- BigIntegerAddInt(g, g, 1); /* ++g */
- else
- break;
- }
-
- BigIntegerFree(u);
- BigIntegerFree(t);
-
- tc->tcbuf.modulus.data = tc->modbuf;
- tc->tcbuf.modulus.len = BigIntegerToBytes(n, tc->tcbuf.modulus.data);
- BigIntegerFree(n);
-
- tc->tcbuf.generator.data = tc->genbuf;
- tc->tcbuf.generator.len = BigIntegerToBytes(g, tc->tcbuf.generator.data);
- BigIntegerFree(g);
-
- tc->tcbuf.index = 1;
- return &tc->tcbuf;
-}
-
-_TYPE( struct t_confent * )
-t_newconfent(tc)
- struct t_conf * tc;
-{
- tc->tcbuf.index = 0;
- tc->tcbuf.modulus.data = tc->modbuf;
- tc->tcbuf.modulus.len = 0;
- tc->tcbuf.generator.data = tc->genbuf;
- tc->tcbuf.generator.len = 0;
- return &tc->tcbuf;
-}
-
-_TYPE( void )
-t_putconfent(ent, fp)
- const struct t_confent * ent;
- FILE * fp;
-{
- char strbuf[MAXB64PARAMLEN];
-
- fprintf(fp, "%d:%s:", ent->index,
- t_tob64(strbuf, ent->modulus.data, ent->modulus.len));
- fprintf(fp, "%s\n",
- t_tob64(strbuf, ent->generator.data, ent->generator.len));
-}
-
-int
-BigIntegerBitLen(b)
- BigInteger b;
-{
- return BN_num_bits(b);
-}
-
-int
-BigIntegerCheckPrime(n)
- BigInteger n;
-{
- BN_CTX * ctx = BN_CTX_new();
- int rv = BN_is_prime(n, 25, NULL, ctx, NULL);
- BN_CTX_free(ctx);
- return rv;
-}
-
-unsigned int
-BigIntegerModInt(d, m)
- BigInteger d;
- unsigned int m;
-{
- return BN_mod_word(d, m);
-}
-
-void
-BigIntegerMod(result, d, m)
- BigInteger result, d, m;
-{
- BN_CTX * ctx = BN_CTX_new();
- BN_mod(result, d, m, ctx);
- BN_CTX_free(ctx);
-}
-
-void
-BigIntegerMul(result, m1, m2)
- BigInteger result, m1, m2;
-{
- BN_CTX * ctx = BN_CTX_new();
- BN_mul(result, m1, m2, ctx);
- BN_CTX_free(ctx);
-}
-
-void
-BigIntegerLShift(result, x, bits)
- BigInteger result, x;
- unsigned int bits;
-{
- BN_lshift(result, x, bits);
-}
-
-int BN_is_prime(const BIGNUM *a, int checks, void (*callback)(int,int,void *),
- BN_CTX *ctx_passed, void *cb_arg)
- {
- return BN_is_prime_fasttest(a, checks, callback, ctx_passed, cb_arg, 0);
- }
-
-int BN_is_prime_fasttest(const BIGNUM *a, int checks,
- void (*callback)(int,int,void *),
- BN_CTX *ctx_passed, void *cb_arg,
- int do_trial_division)
- {
- int i, j, ret = -1;
- int k;
- BN_CTX *ctx = NULL;
- BIGNUM *A1, *A1_odd, *check; /* taken from ctx */
- BN_MONT_CTX *mont = NULL;
- const BIGNUM *A = NULL;
-
- if (checks == BN_prime_checks)
- checks = BN_prime_checks_for_size(BN_num_bits(a));
-
- /* first look for small factors */
- if (!BN_is_odd(a))
- return(0);
- if (do_trial_division)
- {
- for (i = 1; i < NUMPRIMES; i++)
- if (BN_mod_word(a, primes[i]) == 0)
- return 0;
- if (callback != NULL) callback(1, -1, cb_arg);
- }
-
- if (ctx_passed != NULL)
- ctx = ctx_passed;
- else
- if ((ctx=BN_CTX_new()) == NULL)
- goto err;
- BN_CTX_start(ctx);
-
- /* A := abs(a) */
- if (a->neg)
- {
- BIGNUM *t;
- if ((t = BN_CTX_get(ctx)) == NULL) goto err;
- BN_copy(t, a);
- t->neg = 0;
- A = t;
- }
- else
- A = a;
- A1 = BN_CTX_get(ctx);
- A1_odd = BN_CTX_get(ctx);
- check = BN_CTX_get(ctx);
- if (check == NULL) goto err;
-
- /* compute A1 := A - 1 */
- if (!BN_copy(A1, A))
- goto err;
- if (!BN_sub_word(A1, 1))
- goto err;
- if (BN_is_zero(A1))
- {
- ret = 0;
- goto err;
- }
-
- /* write A1 as A1_odd * 2^k */
- k = 1;
- while (!BN_is_bit_set(A1, k))
- k++;
- if (!BN_rshift(A1_odd, A1, k))
- goto err;
-
- /* Montgomery setup for computations mod A */
- mont = BN_MONT_CTX_new();
- if (mont == NULL)
- goto err;
- if (!BN_MONT_CTX_set(mont, A, ctx))
- goto err;
-
- for (i = 0; i < checks; i++)
- {
- if (!BN_pseudo_rand(check, BN_num_bits(A1), 0, 0))
- goto err;
- if (BN_cmp(check, A1) >= 0)
- if (!BN_sub(check, check, A1))
- goto err;
- if (!BN_add_word(check, 1))
- goto err;
- /* now 1 <= check < A */
-
- j = witness(check, A, A1, A1_odd, k, ctx, mont);
- if (j == -1) goto err;
- if (j)
- {
- ret=0;
- goto err;
- }
- if (callback != NULL) callback(1,i,cb_arg);
- }
- ret=1;
-err:
- if (ctx != NULL)
- {
- BN_CTX_end(ctx);
- if (ctx_passed == NULL)
- BN_CTX_free(ctx);
- }
- if (mont != NULL)
- BN_MONT_CTX_free(mont);
-
- return(ret);
- }
-
-static int witness(BIGNUM *w, const BIGNUM *a, const BIGNUM *a1,
- const BIGNUM *a1_odd, int k, BN_CTX *ctx, BN_MONT_CTX *mont)
- {
- if (!BN_mod_exp_mont(w, w, a1_odd, a, ctx, mont)) /* w := w^a1_odd mod a */
- return -1;
- if (BN_is_one(w))
- return 0; /* probably prime */
- if (BN_cmp(w, a1) == 0)
- return 0; /* w == -1 (mod a), 'a' is probably prime */
- while (--k)
- {
- if (!BN_mod_mul(w, w, w, a, ctx)) /* w := w^2 mod a */
- return -1;
- if (BN_is_one(w))
- return 1; /* 'a' is composite, otherwise a previous 'w' would
- * have been == -1 (mod 'a') */
- if (BN_cmp(w, a1) == 0)
- return 0; /* w == -1 (mod a), 'a' is probably prime */
- }
- /* If we get here, 'w' is the (a-1)/2-th power of the original 'w',
- * and it is neither -1 nor +1 -- so 'a' cannot be prime */
- return 1;
- }
-
-int BN_mod_exp_mont(BIGNUM *rr, BIGNUM *a, const BIGNUM *p,
- const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *in_mont)
- {
- int i,j,bits,ret=0,wstart,wend,window,wvalue;
- int start=1,ts=0;
- BIGNUM *d,*r;
- BIGNUM *aa;
- BIGNUM val[TABLE_SIZE];
- BN_MONT_CTX *mont=NULL;
-
- bn_check_top(a);
- bn_check_top(p);
- bn_check_top(m);
-
- if (!(m->d[0] & 1))
- {
- return(0);
- }
- bits=BN_num_bits(p);
- if (bits == 0)
- {
- BN_one(rr);
- return(1);
- }
- BN_CTX_start(ctx);
- d = BN_CTX_get(ctx);
- r = BN_CTX_get(ctx);
- if (d == NULL || r == NULL) goto err;
-
- /* If this is not done, things will break in the montgomery
- * part */
-
- if (in_mont != NULL)
- mont=in_mont;
- else
- {
- if ((mont=BN_MONT_CTX_new()) == NULL) goto err;
- if (!BN_MONT_CTX_set(mont,m,ctx)) goto err;
- }
-
- BN_init(&val[0]);
- ts=1;
- if (BN_ucmp(a,m) >= 0)
- {
- if (!BN_mod(&(val[0]),a,m,ctx))
- goto err;
- aa= &(val[0]);
- }
- else
- aa=a;
- if (!BN_to_montgomery(&(val[0]),aa,mont,ctx)) goto err; /* 1 */
-
- window = BN_window_bits_for_exponent_size(bits);
- if (window > 1)
- {
- if (!BN_mod_mul_montgomery(d,&(val[0]),&(val[0]),mont,ctx)) goto err; /* 2 */
- j=1<<(window-1);
- for (i=1; i<j; i++)
- {
- BN_init(&(val[i]));
- if (!BN_mod_mul_montgomery(&(val[i]),&(val[i-1]),d,mont,ctx))
- goto err;
- }
- ts=i;
- }
-
- start=1; /* This is used to avoid multiplication etc
- * when there is only the value '1' in the
- * buffer. */
- wvalue=0; /* The 'value' of the window */
- wstart=bits-1; /* The top bit of the window */
- wend=0; /* The bottom bit of the window */
-
- if (!BN_to_montgomery(r,BN_value_one(),mont,ctx)) goto err;
- for (;;)
- {
- if (BN_is_bit_set(p,wstart) == 0)
- {
- if (!start)
- {
- if (!BN_mod_mul_montgomery(r,r,r,mont,ctx))
- goto err;
- }
- if (wstart == 0) break;
- wstart--;
- continue;
- }
- /* We now have wstart on a 'set' bit, we now need to work out
- * how bit a window to do. To do this we need to scan
- * forward until the last set bit before the end of the
- * window */
- j=wstart;
- wvalue=1;
- wend=0;
- for (i=1; i<window; i++)
- {
- if (wstart-i < 0) break;
- if (BN_is_bit_set(p,wstart-i))
- {
- wvalue<<=(i-wend);
- wvalue|=1;
- wend=i;
- }
- }
-
- /* wend is the size of the current window */
- j=wend+1;
- /* add the 'bytes above' */
- if (!start)
- for (i=0; i<j; i++)
- {
- if (!BN_mod_mul_montgomery(r,r,r,mont,ctx))
- goto err;
- }
-
- /* wvalue will be an odd number < 2^window */
- if (!BN_mod_mul_montgomery(r,r,&(val[wvalue>>1]),mont,ctx))
- goto err;
-
- /* move the 'window' down further */
- wstart-=wend+1;
- wvalue=0;
- start=0;
- if (wstart < 0) break;
- }
- if (!BN_from_montgomery(rr,r,mont,ctx)) goto err;
- ret=1;
-err:
- if ((in_mont == NULL) && (mont != NULL)) BN_MONT_CTX_free(mont);
- BN_CTX_end(ctx);
- for (i=0; i<ts; i++)
- BN_clear_free(&(val[i]));
- return(ret);
- }
-
-BN_ULONG BN_mod_word(const BIGNUM *a, BN_ULONG w)
- {
-#ifndef BN_LLONG
- BN_ULONG ret=0;
-#else
- BN_ULLONG ret=0;
-#endif
- int i;
-
- w&=BN_MASK2;
- for (i=a->top-1; i>=0; i--)
- {
-#ifndef BN_LLONG
- ret=((ret<<BN_BITS4)|((a->d[i]>>BN_BITS4)&BN_MASK2l))%w;
- ret=((ret<<BN_BITS4)|(a->d[i]&BN_MASK2l))%w;
-#else
- ret=(BN_ULLONG)(((ret<<(BN_ULLONG)BN_BITS2)|a->d[i])%
- (BN_ULLONG)w);
-#endif
- }
- return((BN_ULONG)ret);
- }
-
-static int bnrand(int pseudorand, BIGNUM *rnd, int bits, int top, int bottom)
- {
- unsigned char *buf=NULL;
- int ret=0,bit,bytes,mask;
-
- if (bits == 0)
- {
- BN_zero(rnd);
- return 1;
- }
-
- bytes=(bits+7)/8;
- bit=(bits-1)%8;
- mask=0xff<<bit;
-
- buf=(unsigned char *)malloc(bytes);
- if (buf == NULL)
- {
- goto err;
- }
-
- /* make a random number and set the top and bottom bits */
- /* this ignores the pseudorand flag */
-
- t_random(buf, bytes);
-
- if (top)
- {
- if (bit == 0)
- {
- buf[0]=1;
- buf[1]|=0x80;
- }
- else
- {
- buf[0]|=(3<<(bit-1));
- buf[0]&= ~(mask<<1);
- }
- }
- else
- {
- buf[0]|=(1<<bit);
- buf[0]&= ~(mask<<1);
- }
- if (bottom) /* set bottom bits to whatever odd is */
- buf[bytes-1]|=1;
- if (!BN_bin2bn(buf,bytes,rnd)) goto err;
- ret=1;
-err:
- if (buf != NULL)
- {
- memset(buf,0,bytes);
- free(buf);
- }
- return(ret);
- }
-
-/* BN_pseudo_rand is the same as BN_rand, now. */
-
-int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom)
- {
- return bnrand(1, rnd, bits, top, bottom);
- }
-
-#define MONT_WORD /* use the faster word-based algorithm */
-
-int BN_mod_mul_montgomery(BIGNUM *r, BIGNUM *a, BIGNUM *b,
- BN_MONT_CTX *mont, BN_CTX *ctx)
- {
- BIGNUM *tmp,*tmp2;
- int ret=0;
-
- BN_CTX_start(ctx);
- tmp = BN_CTX_get(ctx);
- tmp2 = BN_CTX_get(ctx);
- if (tmp == NULL || tmp2 == NULL) goto err;
-
- bn_check_top(tmp);
- bn_check_top(tmp2);
-
- if (a == b)
- {
- if (!BN_sqr(tmp,a,ctx)) goto err;
- }
- else
- {
- if (!BN_mul(tmp,a,b,ctx)) goto err;
- }
- /* reduce from aRR to aR */
- if (!BN_from_montgomery(r,tmp,mont,ctx)) goto err;
- ret=1;
-err:
- BN_CTX_end(ctx);
- return(ret);
- }
-
-int BN_from_montgomery(BIGNUM *ret, BIGNUM *a, BN_MONT_CTX *mont,
- BN_CTX *ctx)
- {
- int retn=0;
-
-#ifdef MONT_WORD
- BIGNUM *n,*r;
- BN_ULONG *ap,*np,*rp,n0,v,*nrp;
- int al,nl,max,i,x,ri;
-
- BN_CTX_start(ctx);
- if ((r = BN_CTX_get(ctx)) == NULL) goto err;
-
- if (!BN_copy(r,a)) goto err;
- n= &(mont->N);
-
- ap=a->d;
- /* mont->ri is the size of mont->N in bits (rounded up
- to the word size) */
- al=ri=mont->ri/BN_BITS2;
-
- nl=n->top;
- if ((al == 0) || (nl == 0)) { r->top=0; return(1); }
-
- max=(nl+al+1); /* allow for overflow (no?) XXX */
- if (bn_wexpand(r,max) == NULL) goto err;
- if (bn_wexpand(ret,max) == NULL) goto err;
-
- r->neg=a->neg^n->neg;
- np=n->d;
- rp=r->d;
- nrp= &(r->d[nl]);
-
- /* clear the top words of T */
-#if 1
- for (i=r->top; i<max; i++) /* memset? XXX */
- r->d[i]=0;
-#else
- memset(&(r->d[r->top]),0,(max-r->top)*sizeof(BN_ULONG));
-#endif
-
- r->top=max;
- n0=mont->n0;
-
-#ifdef BN_COUNT
- printf("word BN_from_montgomery %d * %d\n",nl,nl);
-#endif
- for (i=0; i<nl; i++)
- {
-#ifdef __TANDEM
- {
- long long t1;
- long long t2;
- long long t3;
- t1 = rp[0] * (n0 & 0177777);
- t2 = 037777600000l;
- t2 = n0 & t2;
- t3 = rp[0] & 0177777;
- t2 = (t3 * t2) & BN_MASK2;
- t1 = t1 + t2;
- v=bn_mul_add_words(rp,np,nl,(BN_ULONG) t1);
- }
-#else
- v=bn_mul_add_words(rp,np,nl,(rp[0]*n0)&BN_MASK2);
-#endif
- nrp++;
- rp++;
- if (((nrp[-1]+=v)&BN_MASK2) >= v)
- continue;
- else
- {
- if (((++nrp[0])&BN_MASK2) != 0) continue;
- if (((++nrp[1])&BN_MASK2) != 0) continue;
- for (x=2; (((++nrp[x])&BN_MASK2) == 0); x++) ;
- }
- }
- bn_fix_top(r);
-
- /* mont->ri will be a multiple of the word size */
-#if 0
- BN_rshift(ret,r,mont->ri);
-#else
- ret->neg = r->neg;
- x=ri;
- rp=ret->d;
- ap= &(r->d[x]);
- if (r->top < x)
- al=0;
- else
- al=r->top-x;
- ret->top=al;
- al-=4;
- for (i=0; i<al; i+=4)
- {
- BN_ULONG t1,t2,t3,t4;
-
- t1=ap[i+0];
- t2=ap[i+1];
- t3=ap[i+2];
- t4=ap[i+3];
- rp[i+0]=t1;
- rp[i+1]=t2;
- rp[i+2]=t3;
- rp[i+3]=t4;
- }
- al+=4;
- for (; i<al; i++)
- rp[i]=ap[i];
-#endif
-#else /* !MONT_WORD */
- BIGNUM *t1,*t2;
-
- BN_CTX_start(ctx);
- t1 = BN_CTX_get(ctx);
- t2 = BN_CTX_get(ctx);
- if (t1 == NULL || t2 == NULL) goto err;
-
- if (!BN_copy(t1,a)) goto err;
- BN_mask_bits(t1,mont->ri);
-
- if (!BN_mul(t2,t1,&mont->Ni,ctx)) goto err;
- BN_mask_bits(t2,mont->ri);
-
- if (!BN_mul(t1,t2,&mont->N,ctx)) goto err;
- if (!BN_add(t2,a,t1)) goto err;
- BN_rshift(ret,t2,mont->ri);
-#endif /* MONT_WORD */
-
- if (BN_ucmp(ret, &(mont->N)) >= 0)
- {
- BN_usub(ret,ret,&(mont->N));
- }
- retn=1;
- err:
- BN_CTX_end(ctx);
- return(retn);
- }
-
-void BN_MONT_CTX_init(BN_MONT_CTX *ctx)
- {
- ctx->ri=0;
- BN_init(&(ctx->RR));
- BN_init(&(ctx->N));
- BN_init(&(ctx->Ni));
- ctx->flags=0;
- }
-
-BN_MONT_CTX *BN_MONT_CTX_new(void)
- {
- BN_MONT_CTX *ret;
-
- if ((ret=(BN_MONT_CTX *)malloc(sizeof(BN_MONT_CTX))) == NULL)
- return(NULL);
-
- BN_MONT_CTX_init(ret);
- ret->flags=BN_FLG_MALLOCED;
- return(ret);
- }
-
-void BN_MONT_CTX_free(BN_MONT_CTX *mont)
- {
- if(mont == NULL)
- return;
-
- BN_free(&(mont->RR));
- BN_free(&(mont->N));
- BN_free(&(mont->Ni));
- if (mont->flags & BN_FLG_MALLOCED)
- free(mont);
- }
-
-int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx)
- {
- BIGNUM Ri,*R;
-
- BN_init(&Ri);
- R= &(mont->RR); /* grab RR as a temp */
- BN_copy(&(mont->N),mod); /* Set N */
-
-#ifdef MONT_WORD
- {
- BIGNUM tmod;
- BN_ULONG buf[2];
-
- mont->ri=(BN_num_bits(mod)+(BN_BITS2-1))/BN_BITS2*BN_BITS2;
- BN_zero(R);
- BN_set_bit(R,BN_BITS2); /* R */
-
- buf[0]=mod->d[0]; /* tmod = N mod word size */
- buf[1]=0;
- tmod.d=buf;
- tmod.top=1;
- tmod.dmax=2;
- tmod.neg=mod->neg;
- /* Ri = R^-1 mod N*/
- if ((BN_mod_inverse(&Ri,R,&tmod,ctx)) == NULL)
- goto err;
- BN_lshift(&Ri,&Ri,BN_BITS2); /* R*Ri */
- if (!BN_is_zero(&Ri))
- BN_sub_word(&Ri,1);
- else /* if N mod word size == 1 */
- BN_set_word(&Ri,BN_MASK2); /* Ri-- (mod word size) */
- BN_div(&Ri,NULL,&Ri,&tmod,ctx); /* Ni = (R*Ri-1)/N,
- * keep only least significant word: */
- mont->n0=Ri.d[0];
- BN_free(&Ri);
- }
-#else /* !MONT_WORD */
- { /* bignum version */
- mont->ri=BN_num_bits(mod);
- BN_zero(R);
- BN_set_bit(R,mont->ri); /* R = 2^ri */
- /* Ri = R^-1 mod N*/
- if ((BN_mod_inverse(&Ri,R,mod,ctx)) == NULL)
- goto err;
- BN_lshift(&Ri,&Ri,mont->ri); /* R*Ri */
- BN_sub_word(&Ri,1);
- /* Ni = (R*Ri-1) / N */
- BN_div(&(mont->Ni),NULL,&Ri,mod,ctx);
- BN_free(&Ri);
- }
-#endif
-
- /* setup RR for conversions */
- BN_zero(&(mont->RR));
- BN_set_bit(&(mont->RR),mont->ri*2);
- BN_mod(&(mont->RR),&(mont->RR),&(mont->N),ctx);
-
- return(1);
-err:
- return(0);
- }
-
-BIGNUM *BN_value_one(void)
- {
- static BN_ULONG data_one=1L;
- static BIGNUM const_one={&data_one,1,1,0};
-
- return(&const_one);
- }
-
-/* solves ax == 1 (mod n) */
-BIGNUM *BN_mod_inverse(BIGNUM *in, BIGNUM *a, const BIGNUM *n, BN_CTX *ctx)
- {
- BIGNUM *A,*B,*X,*Y,*M,*D,*R=NULL;
- BIGNUM *T,*ret=NULL;
- int sign;
-
- bn_check_top(a);
- bn_check_top(n);
-
- BN_CTX_start(ctx);
- A = BN_CTX_get(ctx);
- B = BN_CTX_get(ctx);
- X = BN_CTX_get(ctx);
- D = BN_CTX_get(ctx);
- M = BN_CTX_get(ctx);
- Y = BN_CTX_get(ctx);
- if (Y == NULL) goto err;
-
- if (in == NULL)
- R=BN_new();
- else
- R=in;
- if (R == NULL) goto err;
-
- BN_zero(X);
- BN_one(Y);
- if (BN_copy(A,a) == NULL) goto err;
- if (BN_copy(B,n) == NULL) goto err;
- sign=1;
-
- while (!BN_is_zero(B))
- {
- if (!BN_div(D,M,A,B,ctx)) goto err;
- T=A;
- A=B;
- B=M;
- /* T has a struct, M does not */
-
- if (!BN_mul(T,D,X,ctx)) goto err;
- if (!BN_add(T,T,Y)) goto err;
- M=Y;
- Y=X;
- X=T;
- sign= -sign;
- }
- if (sign < 0)
- {
- if (!BN_sub(Y,n,Y)) goto err;
- }
-
- if (BN_is_one(A))
- { if (!BN_mod(R,Y,n,ctx)) goto err; }
- else
- {
- goto err;
- }
- ret=R;
-err:
- if ((ret == NULL) && (in == NULL)) BN_free(R);
- BN_CTX_end(ctx);
- return(ret);
- }
-
-int BN_set_bit(BIGNUM *a, int n)
- {
- int i,j,k;
-
- i=n/BN_BITS2;
- j=n%BN_BITS2;
- if (a->top <= i)
- {
- if (bn_wexpand(a,i+1) == NULL) return(0);
- for(k=a->top; k<i+1; k++)
- a->d[k]=0;
- a->top=i+1;
- }
-
- a->d[i]|=(((BN_ULONG)1)<<j);
- return(1);
- }
-
projects / openwrt / staging / yousong.git / blobdiff