/* * Copyright (c) 2000-2001 Apple Computer, Inc. All Rights Reserved. * * The contents of this file constitute Original Code as defined in and are * subject to the Apple Public Source License Version 1.2 (the 'License'). * You may not use this file except in compliance with the License. Please obtain * a copy of the License at http://www.apple.com/publicsource and read it before * using this file. * * This Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS * OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, INCLUDING WITHOUT * LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR * PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. Please see the License for the * specific language governing rights and limitations under the License. */ /* crypto/bn/bn_recp.c */ /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) * All rights reserved. * * This package is an SSL implementation written * by Eric Young (eay@cryptsoft.com). * The implementation was written so as to conform with Netscapes SSL. * * This library is free for commercial and non-commercial use as long as * the following conditions are aheared to. The following conditions * apply to all code found in this distribution, be it the RC4, RSA, * lhash, DES, etc., code; not just the SSL code. The SSL documentation * included with this distribution is covered by the same copyright terms * except that the holder is Tim Hudson (tjh@cryptsoft.com). * * Copyright remains Eric Young's, and as such any Copyright notices in * the code are not to be removed. * If this package is used in a product, Eric Young should be given attribution * as the author of the parts of the library used. * This can be in the form of a textual message at program startup or * in documentation (online or textual) provided with the package. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * "This product includes cryptographic software written by * Eric Young (eay@cryptsoft.com)" * The word 'cryptographic' can be left out if the rouines from the library * being used are not cryptographic related :-). * 4. If you include any Windows specific code (or a derivative thereof) from * the apps directory (application code) you must include an acknowledgement: * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" * * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * The licence and distribution terms for any publically available version or * derivative of this code cannot be changed. i.e. this code cannot simply be * copied and put under another distribution licence * [including the GNU Public Licence.] */ #include <stdio.h> #include "cryptlib.h" #include "bn_lcl.h" void BN_RECP_CTX_init(BN_RECP_CTX *recp) { BN_init(&(recp->N)); BN_init(&(recp->Nr)); recp->num_bits=0; recp->flags=0; } BN_RECP_CTX *BN_RECP_CTX_new(void) { BN_RECP_CTX *ret; if ((ret=(BN_RECP_CTX *)Malloc(sizeof(BN_RECP_CTX))) == NULL) return(NULL); BN_RECP_CTX_init(ret); ret->flags=BN_FLG_MALLOCED; return(ret); } void BN_RECP_CTX_free(BN_RECP_CTX *recp) { if(recp == NULL) return; BN_free(&(recp->N)); BN_free(&(recp->Nr)); if (recp->flags & BN_FLG_MALLOCED) Free(recp); } int BN_RECP_CTX_set(BN_RECP_CTX *recp, const BIGNUM *d, BN_CTX *ctx) { BN_copy(&(recp->N),d); BN_zero(&(recp->Nr)); recp->num_bits=BN_num_bits(d); recp->shift=0; return(1); } int BN_mod_mul_reciprocal(BIGNUM *r, BIGNUM *x, BIGNUM *y, BN_RECP_CTX *recp, BN_CTX *ctx) { int ret=0; BIGNUM *a; BN_CTX_start(ctx); if ((a = BN_CTX_get(ctx)) == NULL) goto err; if (y != NULL) { if (x == y) { if (!BN_sqr(a,x,ctx)) goto err; } else { if (!BN_mul(a,x,y,ctx)) goto err; } } else a=x; /* Just do the mod */ BN_div_recp(NULL,r,a,recp,ctx); ret=1; err: BN_CTX_end(ctx); return(ret); } int BN_div_recp(BIGNUM *dv, BIGNUM *rem, BIGNUM *m, BN_RECP_CTX *recp, BN_CTX *ctx) { int i,j,ret=0; BIGNUM *a,*b,*d,*r; BN_CTX_start(ctx); a=BN_CTX_get(ctx); b=BN_CTX_get(ctx); if (dv != NULL) d=dv; else d=BN_CTX_get(ctx); if (rem != NULL) r=rem; else r=BN_CTX_get(ctx); if (a == NULL || b == NULL || d == NULL || r == NULL) goto err; if (BN_ucmp(m,&(recp->N)) < 0) { BN_zero(d); BN_copy(r,m); BN_CTX_end(ctx); return(1); } /* We want the remainder * Given input of ABCDEF / ab * we need multiply ABCDEF by 3 digests of the reciprocal of ab * */ i=BN_num_bits(m); j=recp->num_bits<<1; if (j>i) i=j; j>>=1; if (i != recp->shift) recp->shift=BN_reciprocal(&(recp->Nr),&(recp->N), i,ctx); if (!BN_rshift(a,m,j)) goto err; if (!BN_mul(b,a,&(recp->Nr),ctx)) goto err; if (!BN_rshift(d,b,i-j)) goto err; d->neg=0; if (!BN_mul(b,&(recp->N),d,ctx)) goto err; if (!BN_usub(r,m,b)) goto err; r->neg=0; #if 1 j=0; while (BN_ucmp(r,&(recp->N)) >= 0) { if (j++ > 2) { BNerr(BN_F_BN_MOD_MUL_RECIPROCAL,BN_R_BAD_RECIPROCAL); goto err; } if (!BN_usub(r,r,&(recp->N))) goto err; if (!BN_add_word(d,1)) goto err; } #endif r->neg=BN_is_zero(r)?0:m->neg; d->neg=m->neg^recp->N.neg; ret=1; err: BN_CTX_end(ctx); return(ret); } /* len is the expected size of the result * We actually calculate with an extra word of precision, so * we can do faster division if the remainder is not required. */ int BN_reciprocal(BIGNUM *r, BIGNUM *m, int len, BN_CTX *ctx) { int ret= -1; BIGNUM t; BN_init(&t); BN_zero(&t); if (!BN_set_bit(&t,len)) goto err; if (!BN_div(r,NULL,&t,m,ctx)) goto err; ret=len; err: BN_free(&t); return(ret); }