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Use MONT_WORD macro to control if the word-based or the bignum

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algorithm is used.
This commit is contained in:
Ulf Möller 2000-02-05 18:23:05 +00:00
parent 9b141126d4
commit 6535eb1728
3 changed files with 101 additions and 122 deletions
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1
crypto/bn/bn.h
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@ -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 */

47
crypto/bn/bn_mont.c
View File

@ -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)
{
@ -105,22 +107,17 @@ 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
{
#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;
@ -155,7 +152,7 @@ int BN_from_montgomery(BIGNUM *ret, BIGNUM *a, BN_MONT_CTX *mont,
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<nl; i++)
{
@ -203,18 +200,10 @@ printf("word BN_from_montgomery %d * %d\n",nl,nl);
for (; i<al; i++)
rp[i]=ap[i];
#endif
if (BN_ucmp(ret, &(mont->N)) >= 0)
{
BN_usub(ret,ret,&(mont->N)); /* XXX */
}
retn=1;
}
#ifdef BN_RECURSION_MONT
else /* bignum version */
{
#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;
@ -228,12 +217,13 @@ printf("word BN_from_montgomery %d * %d\n",nl,nl);
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;
if (BN_ucmp(ret, &(mont->N)) >= 0)
{
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);

1
doc/crypto/BN_mod_mul_montgomery.pod
View File

@ -58,7 +58,6 @@ The B<BN_MONT_CTX> 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 */