* [including the GNU Public Licence.]
*/
+/*
+ * Details about Montgomery multiplication algorithms can be found at:
+ * http://www.ece.orst.edu/ISL/Publications.html
+ * http://www.ece.orst.edu/ISL/Koc/papers/j37acmon.pdf
+ */
+
#include <stdio.h>
#include "cryptlib.h"
#include "bn_lcl.h"
-int BN_mod_mul_montgomery(r,a,b,mont,ctx)
-BIGNUM *r,*a,*b;
-BN_MONT_CTX *mont;
-BN_CTX *ctx;
+#define MONT_WORD
+
+int BN_mod_mul_montgomery(BIGNUM *r, BIGNUM *a, BIGNUM *b,
+ BN_MONT_CTX *mont, BN_CTX *ctx)
{
- BIGNUM *tmp;
+ BIGNUM *tmp,*tmp2;
+
+ tmp= &(ctx->bn[ctx->tos]);
+ tmp2= &(ctx->bn[ctx->tos]);
+ ctx->tos+=2;
- tmp=ctx->bn[ctx->tos++];
+ bn_check_top(tmp);
+ bn_check_top(tmp2);
if (a == b)
{
+#if 0
+ bn_wexpand(tmp,a->top*2);
+ bn_wexpand(tmp2,a->top*4);
+ bn_sqr_recursive(tmp->d,a->d,a->top,tmp2->d);
+ tmp->top=a->top*2;
+ if (tmp->d[tmp->top-1] == 0)
+ tmp->top--;
+#else
if (!BN_sqr(tmp,a,ctx)) goto err;
+#endif
}
else
{
- if (!BN_mul(tmp,a,b)) goto err;
+ if (!BN_mul(tmp,a,b,ctx)) goto err;
}
/* reduce from aRR to aR */
if (!BN_from_montgomery(r,tmp,mont,ctx)) goto err;
- ctx->tos--;
+ ctx->tos-=2;
return(1);
err:
return(0);
}
-#define MONT_WORD
-
-#ifdef MONT_WORD
-int BN_from_montgomery(ret,a,mont,ctx)
-BIGNUM *ret;
-BIGNUM *a;
-BN_MONT_CTX *mont;
-BN_CTX *ctx;
+int BN_from_montgomery(BIGNUM *ret, BIGNUM *a, BN_MONT_CTX *mont,
+ BN_CTX *ctx)
{
- BIGNUM *n,*t1,*r;
- BN_ULONG *ap,*np,*rp,n0,v;
- int al,nl,max,i,x,ri;
- int retn=0;
+#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;
+ int retn=0;
- t1=ctx->bn[ctx->tos];
- r=ctx->bn[ctx->tos+1];
+ r= &(ctx->bn[ctx->tos]);
- if (!BN_copy(r,a)) goto err;
- n=mont->N;
+ if (!BN_copy(r,a)) goto err1;
+ n= &(mont->N);
- ap=a->d;
- /* mont->ri is the size of mont->N in bits/words */
- al=ri=mont->ri/BN_BITS2;
+ ap=a->d;
+ /* mont->ri is the size of mont->N in bits/words */
+ al=ri=mont->ri/BN_BITS2;
- nl=n->top;
- if ((al == 0) || (nl == 0)) { r->top=0; return(1); }
+ 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 err1;
+ if (bn_wexpand(ret,max) == NULL) goto err1;
- r->neg=a->neg^n->neg;
- np=n->d;
- rp=r->d;
+ 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; i<max; i++) /* memset? XXX */
- r->d[i]=0;
+ 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));
+ memset(&(r->d[r->top]),0,(max-r->top)*sizeof(BN_ULONG));
#endif
- r->top=max;
- n0=mont->n0;
-
- for (i=0; i<nl; i++)
- {
-#if 0
- int x1,x2;
+ r->top=max;
+ n0=mont->n0;
- if (i+4 > nl)
+#ifdef BN_COUNT
+printf("word BN_from_montgomery %d * %d\n",nl,nl);
+#endif
+ for (i=0; i<nl; i++)
{
- x2=nl;
- x1=0;
+ 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++) ;
+ }
}
+ bn_fix_top(r);
+
+ /* mont->ri will be a multiple of the word size */
+#if 0
+ 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; i<al; i+=4)
{
- x2=i+4;
- x1=nl-x2;
+ 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;
}
- v=bn_mul_add_words(&(rp[x1]),&(np[x1]),x2,(rp[x1]*n0)&BN_MASK2);
-#else
- v=bn_mul_add_words(rp,np,nl,(rp[0]*n0)&BN_MASK2);
+ al+=4;
+ for (; i<al; i++)
+ rp[i]=ap[i];
#endif
- if (((rp[nl]+=v)&BN_MASK2) < v)
+ if (BN_ucmp(ret, &(mont->N)) >= 0)
{
- for (x=(nl+1); (((++rp[x])&BN_MASK2) == 0); x++)
- ;
+ BN_usub(ret,ret,&(mont->N)); /* XXX */
}
- rp++;
+ retn=1;
+err1:
+ return(retn);
}
- while (r->d[r->top-1] == 0)
- r->top--;
-
- /* mont->ri will be a multiple of the word size */
-#if 0
- BN_rshift(ret,r,mont->ri);
-#else
- ap=r->d;
- rp=ret->d;
- x=ri;
- al=r->top-x;
- for (i=0; i<al; i++)
+#ifdef BN_RECURSION_MONT
+ else /* bignum version */
{
- rp[i]=ap[i+x];
- }
- ret->top=al;
+ BIGNUM *t1,*t2,*t3;
+ int j,i;
+
+#ifdef BN_COUNT
+printf("number BN_from_montgomery\n");
#endif
- if (BN_ucmp(ret,mont->N) >= 0)
- {
- bn_qsub(ret,ret,mont->N); /* XXX */
- }
- retn=1;
-err:
- return(retn);
- }
-#else
-int BN_from_montgomery(r,a,mont,ctx)
-BIGNUM *r;
-BIGNUM *a;
-BN_MONT_CTX *mont;
-BN_CTX *ctx;
- {
- BIGNUM *t1,*t2;
+ t1= &(ctx->bn[ctx->tos]);
+ t2= &(ctx->bn[ctx->tos+1]);
+ t3= &(ctx->bn[ctx->tos+2]);
- t1=ctx->bn[ctx->tos];
- t2=ctx->bn[ctx->tos+1];
+ i=mont->Ni.top;
+ bn_wexpand(ret,i); /* perhaps only i*2 */
+ bn_wexpand(t1,i*4); /* perhaps only i*2 */
+ bn_wexpand(t2,i*2); /* perhaps only i */
- if (!BN_copy(t1,a)) goto err;
- /* can cheat */
- BN_mask_bits(t1,mont->ri);
+ bn_mul_low_recursive(t2->d,a->d,mont->Ni.d,i,t1->d);
- if (!BN_mul(t2,t1,mont->Ni)) goto err;
- BN_mask_bits(t2,mont->ri);
+ BN_zero(t3);
+ BN_set_bit(t3,mont->N.top*BN_BITS2);
+ bn_sub_words(t3->d,t3->d,a->d,i);
+ bn_mul_high(ret->d,t2->d,mont->N.d,t3->d,i,t1->d);
- if (!BN_mul(t1,t2,mont->N)) goto err;
- if (!BN_add(t2,a,t1)) goto err;
- BN_rshift(r,t2,mont->ri);
+ /* hmm... if a is between i and 2*i, things are bad */
+ if (a->top > i)
+ {
+ j=(int)(bn_add_words(ret->d,ret->d,&(a->d[i]),i));
+ if (j) /* overflow */
+ bn_sub_words(ret->d,ret->d,mont->N.d,i);
+ }
+ ret->top=i;
+ bn_fix_top(ret);
+ if (a->d[0])
+ BN_add_word(ret,1); /* Always? */
+ else /* Very very rare */
+ {
+ for (i=1; i<mont->N.top-1; i++)
+ {
+ if (a->d[i])
+ {
+ BN_add_word(ret,1); /* Always? */
+ break;
+ }
+ }
+ }
- if (BN_ucmp(r,mont->N) >= 0)
- bn_qsub(r,r,mont->N);
+ if (BN_ucmp(ret,&(mont->N)) >= 0)
+ BN_usub(ret,ret,&(mont->N));
- return(1);
-err:
- return(0);
- }
+ return(1);
+ }
#endif
+ }
-BN_MONT_CTX *BN_MONT_CTX_new()
+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);
- ret->ri=0;
- ret->RR=BN_new();
- ret->N=BN_new();
- ret->Ni=NULL;
- if ((ret->RR == NULL) || (ret->N == NULL))
- {
- BN_MONT_CTX_free(ret);
- return(NULL);
- }
+
+ BN_MONT_CTX_init(ret);
+ ret->flags=BN_FLG_MALLOCED;
return(ret);
}
-void BN_MONT_CTX_free(mont)
-BN_MONT_CTX *mont;
+void BN_MONT_CTX_init(BN_MONT_CTX *ctx)
+ {
+ ctx->use_word=0;
+ ctx->ri=0;
+ BN_init(&(ctx->RR));
+ BN_init(&(ctx->N));
+ BN_init(&(ctx->Ni));
+ ctx->flags=0;
+ }
+
+void BN_MONT_CTX_free(BN_MONT_CTX *mont)
{
- if (mont->RR != NULL) BN_free(mont->RR);
- if (mont->N != NULL) BN_free(mont->N);
- if (mont->Ni != NULL) BN_free(mont->Ni);
- Free(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(mont,mod,ctx)
-BN_MONT_CTX *mont;
-BIGNUM *mod;
-BN_CTX *ctx;
+int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx)
{
- BIGNUM *Ri=NULL,*R=NULL;
-
- if (mont->RR == NULL) mont->RR=BN_new();
- if (mont->N == NULL) mont->N=BN_new();
-
- R=mont->RR; /* grab RR as a temp */
- BN_copy(mont->N,mod); /* Set N */
-
-#ifdef MONT_WORD
-{
- BIGNUM tmod;
- BN_ULONG buf[2];
- /* int z; */
-
- mont->ri=(BN_num_bits(mod)+(BN_BITS2-1))/BN_BITS2*BN_BITS2;
- BN_lshift(R,BN_value_one(),BN_BITS2); /* R */
- /* I was bad, this modification of a passed variable was
- * breaking the multithreaded stuff :-(
- * z=mod->top;
- * mod->top=1; */
-
- buf[0]=mod->d[0];
- buf[1]=0;
- tmod.d=buf;
- tmod.top=1;
- tmod.max=mod->max;
- tmod.neg=mod->neg;
-
- if ((Ri=BN_mod_inverse(R,&tmod,ctx)) == NULL) goto err; /* Ri */
- BN_lshift(Ri,Ri,BN_BITS2); /* R*Ri */
- bn_qsub(Ri,Ri,BN_value_one()); /* R*Ri - 1 */
- BN_div(Ri,NULL,Ri,&tmod,ctx);
- mont->n0=Ri->d[0];
- BN_free(Ri);
- /* mod->top=z; */
-}
+ BIGNUM Ri,*R;
+
+ BN_init(&Ri);
+ R= &(mont->RR); /* grab RR as a temp */
+ BN_copy(&(mont->N),mod); /* Set N */
+
+#ifdef BN_RECURSION_MONT
+ if (mont->N.top < BN_MONT_CTX_SET_SIZE_WORD)
+#endif
+ {
+ 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);
+ /* I was bad, this modification of a passed variable was
+ * breaking the multithreaded stuff :-(
+ * z=mod->top;
+ * mod->top=1; */
+
+ buf[0]=mod->d[0];
+ buf[1]=0;
+ tmod.d=buf;
+ tmod.top=1;
+ tmod.max=mod->max;
+ tmod.neg=mod->neg;
+
+ if ((BN_mod_inverse(&Ri,R,&tmod,ctx)) == NULL)
+ goto err;
+ BN_lshift(&Ri,&Ri,BN_BITS2); /* R*Ri */
+ if (!BN_is_zero(&Ri))
+ {
+#if 1
+ BN_sub_word(&Ri,1);
#else
- mont->ri=BN_num_bits(mod);
- BN_lshift(R,BN_value_one(),mont->ri); /* R */
- if ((Ri=BN_mod_inverse(R,mod,ctx)) == NULL) goto err; /* Ri */
- BN_lshift(Ri,Ri,mont->ri); /* R*Ri */
- bn_qsub(Ri,Ri,BN_value_one()); /* R*Ri - 1 */
- BN_div(Ri,NULL,Ri,mod,ctx);
- if (mont->Ni != NULL) BN_free(mont->Ni);
- mont->Ni=Ri; /* Ni=(R*Ri-1)/N */
+ BN_usub(&Ri,&Ri,BN_value_one()); /* R*Ri - 1 */
+#endif
+ }
+ else
+ {
+ /* This is not common..., 1 in BN_MASK2,
+ * It happens when buf[0] was == 1. So for 8 bit,
+ * this is 1/256, 16bit, 1 in 2^16 etc.
+ */
+ BN_set_word(&Ri,BN_MASK2);
+ }
+ BN_div(&Ri,NULL,&Ri,&tmod,ctx);
+ mont->n0=Ri.d[0];
+ BN_free(&Ri);
+ /* mod->top=z; */
+ }
+#ifdef BN_RECURSION_MONT
+ else
+ {
+ mont->use_word=0;
+ mont->ri=(BN_num_bits(mod)+(BN_BITS2-1))/BN_BITS2*BN_BITS2;
+#if 1
+ BN_zero(R);
+ BN_set_bit(R,mont->ri);
+#else
+ BN_lshift(R,BN_value_one(),mont->ri); /* R */
+#endif
+ if ((BN_mod_inverse(&Ri,R,mod,ctx)) == NULL)
+ goto err;
+ BN_lshift(&Ri,&Ri,mont->ri); /* R*Ri */
+#if 1
+ BN_sub_word(&Ri,1);
+#else
+ BN_usub(&Ri,&Ri,BN_value_one()); /* R*Ri - 1 */
+#endif
+ BN_div(&(mont->Ni),NULL,&Ri,mod,ctx);
+ BN_free(&Ri);
+ }
#endif
/* setup RR for conversions */
+#if 1
+ BN_zero(&(mont->RR));
+ BN_set_bit(&(mont->RR),mont->ri*2);
+#else
BN_lshift(mont->RR,BN_value_one(),mont->ri*2);
- BN_mod(mont->RR,mont->RR,mont->N,ctx);
+#endif
+ BN_mod(&(mont->RR),&(mont->RR),&(mont->N),ctx);
return(1);
err:
return(0);
}
+BN_MONT_CTX *BN_MONT_CTX_copy(BN_MONT_CTX *to, BN_MONT_CTX *from)
+ {
+ if (to == from) return(to);
+
+ 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);
+ }
+
projects / openssl.git / blobdiff