From 6535eb1728a7d30673d0a95da5fd18126b7d0b71 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ulf=20M=C3=B6ller?= Date: Sat, 5 Feb 2000 18:23:05 +0000 Subject: [PATCH] Use MONT_WORD macro to control if the word-based or the bignum algorithm is used. --- crypto/bn/bn.h | 1 - crypto/bn/bn_mont.c | 209 ++++++++++++--------------- doc/crypto/BN_mod_mul_montgomery.pod | 1 - 3 files changed, 95 insertions(+), 116 deletions(-) diff --git a/crypto/bn/bn.h b/crypto/bn/bn.h index 8ac8acd116..472eb2c616 100644 --- a/crypto/bn/bn.h +++ b/crypto/bn/bn.h @@ -260,7 +260,6 @@ typedef struct bn_blinding_st /* Used for montgomery multiplication */ typedef struct bn_mont_ctx_st { - int use_word; /* 0 for word form, 1 for bignum form */ int ri; /* number of bits in R */ BIGNUM RR; /* used to convert to montgomery form */ BIGNUM N; /* The modulus */ diff --git a/crypto/bn/bn_mont.c b/crypto/bn/bn_mont.c index 35a30a0eeb..7bb0b91223 100644 --- a/crypto/bn/bn_mont.c +++ b/crypto/bn/bn_mont.c @@ -67,6 +67,8 @@ #include "cryptlib.h" #include "bn_lcl.h" +#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) { @@ -105,135 +107,123 @@ err: return(0); } -#define BN_RECURSION_MONT - int BN_from_montgomery(BIGNUM *ret, BIGNUM *a, BN_MONT_CTX *mont, BN_CTX *ctx) { int retn=0; - BN_CTX_start(ctx); - -#ifdef BN_RECURSION_MONT - if (mont->use_word) -#endif - { - BIGNUM *n,*r; - BN_ULONG *ap,*np,*rp,n0,v,*nrp; - int al,nl,max,i,x,ri; - if ((r = BN_CTX_get(ctx)) == NULL) goto err; +#ifdef MONT_WORD + BIGNUM *n,*r; + BN_ULONG *ap,*np,*rp,n0,v,*nrp; + int al,nl,max,i,x,ri; - if (!BN_copy(r,a)) goto err; - n= &(mont->N); + BN_CTX_start(ctx); + if ((r = BN_CTX_get(ctx)) == NULL) goto err; - 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; + if (!BN_copy(r,a)) goto err; + n= &(mont->N); - nl=n->top; - if ((al == 0) || (nl == 0)) { r->top=0; return(1); } + 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; + 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]); + r->neg=a->neg^n->neg; + np=n->d; + rp=r->d; + nrp= &(r->d[nl]); - /* clear the top words of T */ + /* clear the top words of T */ #if 1 - for (i=r->top; id[i]=0; + for (i=r->top; id[i]=0; #else - memset(&(r->d[r->top]),0,(max-r->top)*sizeof(BN_ULONG)); + memset(&(r->d[r->top]),0,(max-r->top)*sizeof(BN_ULONG)); #endif - r->top=max; - n0=mont->n0; + r->top=max; + n0=mont->n0; #ifdef BN_COUNT -printf("word BN_from_montgomery %d * %d\n",nl,nl); + printf("word BN_from_montgomery %d * %d\n",nl,nl); #endif - for (i=0; i= v) + continue; + else { - v=bn_mul_add_words(rp,np,nl,(rp[0]*n0)&BN_MASK2); - 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++) ; - } + 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 */ + } + bn_fix_top(r); + + /* mont->ri will be a multiple of the word size */ #if 0 - BN_rshift(ret,r,mont->ri); + BN_rshift(ret,r,mont->ri); #else - 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; id; + ap= &(r->d[x]); + if (r->top < x) + al=0; + else + al=r->top-x; + ret->top=al; + al-=4; + for (i=0; iN)) >= 0) - { - BN_usub(ret,ret,&(mont->N)); /* XXX */ - } - retn=1; - } -#ifdef BN_RECURSION_MONT - else /* bignum version */ + 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) { - BIGNUM *t1,*t2; - - 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); - - if (BN_ucmp(ret,&mont->N) >= 0) - BN_usub(ret,ret,&mont->N); - retn=1; + BN_usub(ret,ret,&(mont->N)); } -#endif + retn=1; err: BN_CTX_end(ctx); return(retn); @@ -253,7 +243,6 @@ BN_MONT_CTX *BN_MONT_CTX_new(void) void BN_MONT_CTX_init(BN_MONT_CTX *ctx) { - ctx->use_word=0; ctx->ri=0; BN_init(&(ctx->RR)); BN_init(&(ctx->N)); @@ -281,16 +270,11 @@ int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx) R= &(mont->RR); /* grab RR as a temp */ BN_copy(&(mont->N),mod); /* Set N */ -#ifdef BN_RECURSION_MONT - /* the word-based algorithm is faster */ - if (mont->N.top > BN_MONT_CTX_SET_SIZE_WORD) -#endif +#ifdef MONT_WORD { BIGNUM tmod; BN_ULONG buf[2]; - mont->use_word=1; - mont->ri=(BN_num_bits(mod)+(BN_BITS2-1))/BN_BITS2*BN_BITS2; BN_zero(R); BN_set_bit(R,BN_BITS2); /* R */ @@ -314,10 +298,8 @@ int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx) mont->n0=Ri.d[0]; BN_free(&Ri); } -#ifdef BN_RECURSION_MONT - else +#else /* !MONT_WORD */ { /* bignum version */ - mont->use_word=0; mont->ri=BN_num_bits(mod); BN_zero(R); BN_set_bit(R,mont->ri); /* R = 2^ri */ @@ -349,7 +331,6 @@ BN_MONT_CTX *BN_MONT_CTX_copy(BN_MONT_CTX *to, BN_MONT_CTX *from) BN_copy(&(to->RR),&(from->RR)); BN_copy(&(to->N),&(from->N)); BN_copy(&(to->Ni),&(from->Ni)); - to->use_word=from->use_word; to->ri=from->ri; to->n0=from->n0; return(to); diff --git a/doc/crypto/BN_mod_mul_montgomery.pod b/doc/crypto/BN_mod_mul_montgomery.pod index f237f7264e..0f0c1375af 100644 --- a/doc/crypto/BN_mod_mul_montgomery.pod +++ b/doc/crypto/BN_mod_mul_montgomery.pod @@ -58,7 +58,6 @@ The B structure is defined as follows: typedef struct bn_mont_ctx_st { - int use_word; /* 0 for word form, 1 for bignum form */ int ri; /* number of bits in R */ BIGNUM RR; /* R^2 (used to convert to Montgomery form) */ BIGNUM N; /* The modulus */ -- 2.25.1