* [including the GNU Public Licence.]
*/
+#define OPENSSL_FIPSAPI
+
#include <stdio.h>
#include "cryptlib.h"
#include "bn_lcl.h"
-int BN_mod_mul_reciprocal(r, x, y, m, i, nb, ctx)
-BIGNUM *r;
-BIGNUM *x;
-BIGNUM *y;
-BIGNUM *m;
-BIGNUM *i;
-int nb;
-BN_CTX *ctx;
+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 *)OPENSSL_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)
{
- int ret=0,j;
- BIGNUM *a,*b,*c,*d;
+ if(recp == NULL)
+ return;
+
+ BN_free(&(recp->N));
+ BN_free(&(recp->Nr));
+ if (recp->flags & BN_FLG_MALLOCED)
+ OPENSSL_free(recp);
+ }
+
+int BN_RECP_CTX_set(BN_RECP_CTX *recp, const BIGNUM *d, BN_CTX *ctx)
+ {
+ if (!BN_copy(&(recp->N),d)) return 0;
+ BN_zero(&(recp->Nr));
+ recp->num_bits=BN_num_bits(d);
+ recp->shift=0;
+ return(1);
+ }
+
+int BN_mod_mul_reciprocal(BIGNUM *r, const BIGNUM *x, const BIGNUM *y,
+ BN_RECP_CTX *recp, BN_CTX *ctx)
+ {
+ int ret=0;
+ BIGNUM *a;
+ const BIGNUM *ca;
+
+ 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; }
+ ca = a;
+ }
+ else
+ ca=x; /* Just do the mod */
+
+ ret = BN_div_recp(NULL,r,ca,recp,ctx);
+err:
+ BN_CTX_end(ctx);
+ bn_check_top(r);
+ return(ret);
+ }
- a=ctx->bn[ctx->tos++];
- b=ctx->bn[ctx->tos++];
- c=ctx->bn[ctx->tos++];
- d=ctx->bn[ctx->tos++];
+int BN_div_recp(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m,
+ BN_RECP_CTX *recp, BN_CTX *ctx)
+ {
+ int i,j,ret=0;
+ BIGNUM *a,*b,*d,*r;
- if (x == y)
- { if (!BN_sqr(a,x,ctx)) goto err; }
+ 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
- { if (!BN_mul(a,x,y)) goto err; }
- if (!BN_rshift(d,a,nb)) goto err;
- if (!BN_mul(b,d,i)) goto err;
- if (!BN_rshift(c,b,nb)) goto err;
- if (!BN_mul(b,m,c)) goto err;
- if (!BN_sub(r,a,b)) goto err;
+ 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);
+ if (!BN_copy(r,m)) return 0;
+ 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 := max(BN_num_bits(m), 2*BN_num_bits(N)) */
+ i=BN_num_bits(m);
+ j=recp->num_bits<<1;
+ if (j>i) i=j;
+
+ /* Nr := round(2^i / N) */
+ if (i != recp->shift)
+ recp->shift=BN_reciprocal(&(recp->Nr),&(recp->N),
+ i,ctx); /* BN_reciprocal returns i, or -1 for an error */
+ if (recp->shift == -1) goto err;
+
+ /* d := |round(round(m / 2^BN_num_bits(N)) * recp->Nr / 2^(i - BN_num_bits(N)))|
+ * = |round(round(m / 2^BN_num_bits(N)) * round(2^i / N) / 2^(i - BN_num_bits(N)))|
+ * <= |(m / 2^BN_num_bits(N)) * (2^i / N) * (2^BN_num_bits(N) / 2^i)|
+ * = |m/N|
+ */
+ if (!BN_rshift(a,m,recp->num_bits)) goto err;
+ if (!BN_mul(b,a,&(recp->Nr),ctx)) goto err;
+ if (!BN_rshift(d,b,i-recp->num_bits)) 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_cmp(r,m) >= 0)
+ while (BN_ucmp(r,&(recp->N)) >= 0)
{
if (j++ > 2)
{
- BNerr(BN_F_BN_MOD_MUL_RECIPROCAL,BN_R_BAD_RECIPROCAL);
+ BNerr(BN_F_BN_DIV_RECP,BN_R_BAD_RECIPROCAL);
goto err;
}
- if (!BN_sub(r,r,m)) 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:
- ctx->tos-=4;
+ BN_CTX_end(ctx);
+ bn_check_top(dv);
+ bn_check_top(rem);
return(ret);
- }
+ }
-int BN_reciprocal(r, m,ctx)
-BIGNUM *r;
-BIGNUM *m;
-BN_CTX *ctx;
+/* 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.
+ */
+/* r := 2^len / m */
+int BN_reciprocal(BIGNUM *r, const BIGNUM *m, int len, BN_CTX *ctx)
{
- int nm,ret= -1;
+ int ret= -1;
BIGNUM *t;
- t=ctx->bn[ctx->tos++];
+ BN_CTX_start(ctx);
+ if((t = BN_CTX_get(ctx)) == NULL) goto err;
- nm=BN_num_bits(m);
- if (!BN_lshift(t,BN_value_one(),nm*2)) goto err;
+ if (!BN_set_bit(t,len)) goto err;
if (!BN_div(r,NULL,t,m,ctx)) goto err;
- ret=nm;
+
+ ret=len;
err:
- ctx->tos--;
+ bn_check_top(r);
+ BN_CTX_end(ctx);
return(ret);
}
-