X-Git-Url: https://git.cryptolib.org/?a=blobdiff_plain;f=bigint%2Fbigint.c;h=3e2f0eb295241651d679faa9f04f3df723db01d1;hb=35dc9566e40c9f68fa216c70eaa6d5b0597448fe;hp=fb2f524cfc2fedc0227a3ee5c2903e1d64b15de9;hpb=eb09a2a6f447833e3cf73a71fc0113f84d51f41b;p=avr-crypto-lib.git

diff --git a/bigint/bigint.c b/bigint/bigint.c
index fb2f524..3e2f0eb 100644
--- a/bigint/bigint.c
+++ b/bigint/bigint.c
@@ -26,12 +26,16 @@
  */
  
 
+#define STRING2(x) #x
+#define STRING(x) STRING2(x)
+#define STR_LINE STRING(__LINE__)
+
 #include "bigint.h"
 #include <string.h>
-
-#include "bigint_io.h"
+/*
 #include "cli.h"
-
+#include "bigint_io.h"
+*/
 #ifndef MAX
  #define MAX(a,b) (((a)>(b))?(a):(b))
 #endif
@@ -73,15 +77,14 @@ void bigint_adjust(bigint_t* a){
 /******************************************************************************/
 
 void bigint_copy(bigint_t* dest, const bigint_t* src){
-	memcpy(dest->wordv, src->wordv, src->length_B);
 	dest->length_B = src->length_B;
 	dest->info = src->info;
+	memcpy(dest->wordv, src->wordv, src->length_B);
 }
 
 /******************************************************************************/
 
 /* this should be implemented in assembly */
-/*
 void bigint_add_u(bigint_t* dest, const bigint_t* a, const bigint_t* b){
 	uint16_t t=0, i;
 	if(a->length_B < b->length_B){
@@ -101,7 +104,7 @@ void bigint_add_u(bigint_t* dest, const bigint_t* a, const bigint_t* b){
 	dest->length_B = i;
 	bigint_adjust(dest);
 }
-*/
+
 /******************************************************************************/
 
 /* this should be implemented in assembly */
@@ -164,29 +167,8 @@ void bigint_sub_u(bigint_t* dest, const bigint_t* a, const bigint_t* b){
 			return;
 	}
 	if(r<0){
-		for(i=0; i<min; ++i){
-			t = a->wordv[i] - b->wordv[i] - borrow;
-			if(t<1){
-				borrow = 0;
-				dest->wordv[i]=(uint8_t)(-t);
-			}else{
-				borrow = -1;
-				dest->wordv[i]=(uint8_t)(-t);
-			}
-		}
-		for(;i<max; ++i){
-			t = b->wordv[i] + borrow;
-			if(t<1){
-				borrow = 0;
-				dest->wordv[i]=(uint8_t)t;
-			}else{
-				borrow = -1;
-				dest->wordv[i]=(uint8_t)t;
-			}
-		}
+		bigint_sub_u(dest, b, a);
 		SET_NEG(dest);
-		dest->length_B = i;
-		bigint_adjust(dest);
 	}else{
 		for(i=0; i<min; ++i){
 			t = a->wordv[i] - b->wordv[i] - borrow;
@@ -224,12 +206,6 @@ int8_t bigint_cmp_u(const bigint_t* a, const bigint_t* b){
 	if(a->length_B < b->length_B){
 		return -1;
 	}
-	if(GET_FBS(a) > GET_FBS(b)){
-		return 1;
-	}
-	if(GET_FBS(a) < GET_FBS(b)){
-		return -1;
-	}
 	if(a->length_B==0){
 		return 0;
 	}
@@ -304,6 +280,9 @@ void bigint_sub_s(bigint_t* dest, const bigint_t* a, const bigint_t* b){
 
 int8_t bigint_cmp_s(const bigint_t* a, const bigint_t* b){
 	uint8_t s;
+	if(a->length_B==0 && b->length_B==0){
+		return 0;
+	}
 	s  = GET_SIGN(a)?2:0;
 	s |= GET_SIGN(b)?1:0;
 	switch(s){
@@ -344,19 +323,18 @@ void bigint_shiftleft(bigint_t* a, uint16_t shift){
 				t >>= 8;
 			}
 			a->wordv[i] = (uint8_t)t;
+			byteshift++;
 		}else{ /* shift to the right */
-			bitshift = 8 - bitshift;
-			for(i=a->length_B+byteshift-1; i>byteshift; --i){
-				t |= (a->wordv[i])<<(8-bitshift);
+			for(i=a->length_B+byteshift-1; i>byteshift-1; --i){
+				t |= (a->wordv[i])<<(bitshift);
 				a->wordv[i] = (uint8_t)(t>>8);
 				t <<= 8;
 			}
-			t |= (a->wordv[i])<<(8-bitshift);
+			t |= (a->wordv[i])<<(bitshift);
 			a->wordv[i] = (uint8_t)(t>>8);
 		}
-
 	}
-	a->length_B += byteshift+1;
+	a->length_B += byteshift;
 	bigint_adjust(a);
 }
 
@@ -370,15 +348,11 @@ void bigint_shiftright(bigint_t* a, uint16_t shift){
 	byteshift = shift/8;
 	bitshift = shift&7;
 	if(byteshift >= a->length_B){ /* we would shift out more than we have */
-		a->length_B=0;
-		a->wordv[0] = 0;
-		SET_FBS(a, 0);
+		bigint_set_zero(a);
 		return;
 	}
 	if(byteshift == a->length_B-1 && bitshift>GET_FBS(a)){
-		a->length_B=0;
-		a->wordv[0] = 0;
-		SET_FBS(a, 0);
+		bigint_set_zero(a);
 		return;
 	}
 	if(byteshift){
@@ -422,7 +396,14 @@ void bigint_set_zero(bigint_t* a){
 void bigint_mul_u(bigint_t* dest, const bigint_t* a, const bigint_t* b){
 	if(a->length_B==0 || b->length_B==0){
 		bigint_set_zero(dest);
-		depth -= 1;
+		return;
+	}
+	if(dest==a || dest==b){
+		bigint_t d;
+		uint8_t d_b[a->length_B+b->length_B];
+		d.wordv = d_b;
+		bigint_mul_u(&d, a, b);
+		bigint_copy(dest, &d);
 		return;
 	}
 	if(a->length_B==1 || b->length_B==1){
@@ -488,7 +469,6 @@ void bigint_mul_u(bigint_t* dest, const bigint_t* a, const bigint_t* b){
 	/* now we have split up a and b */
 	uint8_t  tmp_b[2*n+2], m_b[2*(n+1)];
 	bigint_t tmp, tmp2, m;
-	/* calculate h=xh*yh; l=xl*yl; sx=xh+xl; sy=yh+yl */
 	tmp.wordv = tmp_b;
 	tmp2.wordv = tmp_b+n+1;
 	m.wordv = m_b;
@@ -496,7 +476,7 @@ void bigint_mul_u(bigint_t* dest, const bigint_t* a, const bigint_t* b){
 	bigint_mul_u(dest, &xl, &yl);  /* dest <= xl*yl     */
 	bigint_add_u(&tmp2, &xh, &xl); /* tmp2 <= xh+xl     */
 	bigint_add_u(&tmp, &yh, &yl);  /* tmp  <= yh+yl     */
-	bigint_mul_u(&m, &tmp2, &tmp); /* m    <= tmp*tmp   */
+	bigint_mul_u(&m, &tmp2, &tmp); /* m    <= tmp2*tmp  */
 	bigint_mul_u(&tmp, &xh, &yh);  /* h    <= xh*yh     */
 	bigint_sub_u(&m, &m, dest);    /* m    <= m-dest    */
     bigint_sub_u(&m, &m, &tmp);    /* m    <= m-h       */
@@ -547,6 +527,14 @@ void bigint_square(bigint_t* dest, const bigint_t* a){
 		bigint_adjust(dest);
 		return;
 	}
+	if(dest==a){
+		bigint_t d;
+		uint8_t d_b[a->length_B*2];
+		d.wordv = d_b;
+		bigint_square(&d, a);
+		bigint_copy(dest, &d);
+		return;
+	}
 	uint16_t n;
 	n=(a->length_B+1)/2;
 	bigint_t xh, xl, tmp; /* x-high, x-low, temp */
@@ -562,9 +550,254 @@ void bigint_square(bigint_t* dest, const bigint_t* a){
 	bigint_mul_u(&tmp, &xl, &xh);
 	bigint_shiftleft(&tmp, 1);
 	bigint_add_scale_u(dest, &tmp, n);
+}
+
+/******************************************************************************/
 
+void bigint_sub_u_bitscale(bigint_t* a, const bigint_t* b, uint16_t bitscale){
+	bigint_t tmp;
+	uint8_t tmp_b[b->length_B+1];
+	uint16_t i,j,byteshift=bitscale/8;
+	uint8_t borrow=0;
+	int16_t t;
+
+	if(a->length_B < b->length_B+byteshift){
+		bigint_set_zero(a);
+		return;
+	}
+
+	tmp.wordv = tmp_b;
+	bigint_copy(&tmp, b);
+	bigint_shiftleft(&tmp, bitscale&7);
+
+	for(j=0,i=byteshift; i<tmp.length_B+byteshift; ++i, ++j){
+		t = a->wordv[i] - tmp.wordv[j] - borrow;
+		a->wordv[i] = (uint8_t)t;
+		if(t<0){
+			borrow = 1;
+		}else{
+			borrow = 0;
+		}
+	}
+	while(borrow){
+		if(i+1 > a->length_B){
+			bigint_set_zero(a);
+			return;
+		}
+		a->wordv[i] -= borrow;
+		if(a->wordv[i]!=0xff){
+			borrow=0;
+		}
+		++i;
+	}
+	bigint_adjust(a);
 }
 
+/******************************************************************************/
+
+void bigint_reduce(bigint_t* a, const bigint_t* r){
+//	bigint_adjust(r);
+	uint8_t rfbs = GET_FBS(r);
+
+	if(r->length_B==0 || a->length_B==0){
+		return;
+	}
+	while(a->length_B > r->length_B){
+		bigint_sub_u_bitscale(a, r, (a->length_B-r->length_B)*8+GET_FBS(a)-rfbs-1);
+	}
+	while((GET_FBS(a) > rfbs+1) && (a->length_B == r->length_B)){
+		bigint_sub_u_bitscale(a, r, GET_FBS(a)-rfbs-1);
+	}
+	while(bigint_cmp_u(a,r)>=0){
+		bigint_sub_u(a,a,r);
+	}
+}
+
+/******************************************************************************/
+
+/* calculate dest = a**exp % r */
+/* using square&multiply */
+void bigint_expmod_u(bigint_t* dest, const bigint_t* a, const bigint_t* exp, const bigint_t* r){
+	if(a->length_B==0 || r->length_B==0){
+		return;
+	}
+
+	bigint_t res, base;
+	uint8_t base_b[MAX(a->length_B,r->length_B*2)], res_b[r->length_B*2];
+	uint16_t i;
+	uint8_t j, t;
+	res.wordv = res_b;
+	base.wordv = base_b;
+	bigint_copy(&base, a);
+	bigint_reduce(&base, r);
+	res.wordv[0]=1;
+	res.length_B=1;
+	res.info = 0;
+	bigint_adjust(&res);
+	for(i=0; i+1<exp->length_B; ++i){
+		t=exp->wordv[i];
+		for(j=0; j<8; ++j){
+			if(t&1){
+				bigint_mul_u(&res, &res, &base);
+				bigint_reduce(&res, r);
+			}
+			bigint_square(&base, &base);
+			bigint_reduce(&base, r);
+			t>>=1;
+		}
+	}
+	t=exp->wordv[i];
+	while(t){
+		if(t&1){
+			bigint_mul_u(&res, &res, &base);
+			bigint_reduce(&res, r);
+		}
+		bigint_square(&base, &base);
+		bigint_reduce(&base, r);
+		t>>=1;
+	}
+	SET_POS(&res);
+	bigint_copy(dest, &res);
+}
+
+/******************************************************************************/
+/* gcd <-- gcd(x,y) a*x+b*y=gcd */
+void bigint_gcdext(bigint_t* gcd, bigint_t* a, bigint_t* b, const bigint_t* x, const bigint_t* y){
+	 bigint_t g, x_, y_, u, v, a_, b_, c_, d_;
+	 volatile uint16_t i=0;
+	 if(x->length_B==0 || y->length_B==0){
+		 return;
+	 }
+	 while(x->wordv[i]==0 && y->wordv[i]==0){
+		 ++i;
+	 }
+	 uint8_t g_b[i+2], x_b[x->length_B-i], y_b[y->length_B-i];
+	 uint8_t u_b[x->length_B-i], v_b[y->length_B-i];
+	 uint8_t a_b[y->length_B+2], c_b[y->length_B+2];
+	 uint8_t b_b[x->length_B+2], d_b[x->length_B+2];
+
+	 g.wordv = g_b;
+	 x_.wordv = x_b;
+	 y_.wordv = y_b;
+	 memset(g_b, 0, i);
+	 g_b[i]=1;
+	 g.length_B = i+1;
+	 g.info=0;
+	 x_.info = y_.info = 0;
+	 x_.length_B = x->length_B-i;
+	 y_.length_B = y->length_B-i;
+	 memcpy(x_.wordv, x->wordv+i, x_.length_B);
+	 memcpy(y_.wordv, y->wordv+i, y_.length_B);
+	 for(i=0; (x_.wordv[0]&(1<<i))==0 && (y_.wordv[0]&(1<<i))==0; ++i){
+	 }
+
+	 bigint_adjust(&x_);
+	 bigint_adjust(&y_);
+
+	 if(i){
+		 bigint_shiftleft(&g, i);
+		 bigint_shiftright(&x_, i);
+		 bigint_shiftright(&y_, i);
+	 }
+	 u.wordv = u_b;
+	 v.wordv = v_b;
+	 a_.wordv = a_b;
+	 b_.wordv = b_b;
+	 c_.wordv = c_b;
+	 d_.wordv = d_b;
+
+	 bigint_copy(&u, &x_);
+	 bigint_copy(&v, &y_);
+	 a_.wordv[0] = 1;
+	 a_.length_B = 1;
+	 a_.info = 0;
+	 d_.wordv[0] = 1;
+	 d_.length_B = 1;
+	 d_.info = 0;
+	 bigint_set_zero(&b_);
+	 bigint_set_zero(&c_);
+	 do{
+		 while((u.wordv[0]&1)==0){
+			 bigint_shiftright(&u, 1);
+			 if((a_.wordv[0]&1) || (b_.wordv[0]&1)){
+				 bigint_add_s(&a_, &a_, &y_);
+				 bigint_sub_s(&b_, &b_, &x_);
+			 }
+			 bigint_shiftright(&a_, 1);
+			 bigint_shiftright(&b_, 1);
+		 }
+		 while((v.wordv[0]&1)==0){
+			 bigint_shiftright(&v, 1);
+			 if((c_.wordv[0]&1) || (d_.wordv[0]&1)){
+				 bigint_add_s(&c_, &c_, &y_);
+				 bigint_sub_s(&d_, &d_, &x_);
+			 }
+			 bigint_shiftright(&c_, 1);
+			 bigint_shiftright(&d_, 1);
+
+		 }
+		 if(bigint_cmp_u(&u, &v)>=0){
+			bigint_sub_u(&u, &u, &v);
+			bigint_sub_s(&a_, &a_, &c_);
+			bigint_sub_s(&b_, &b_, &d_);
+		 }else{
+			bigint_sub_u(&v, &v, &u);
+			bigint_sub_s(&c_, &c_, &a_);
+			bigint_sub_s(&d_, &d_, &b_);
+		 }
+	 }while(u.length_B);
+	 if(gcd){
+		 bigint_mul_s(gcd, &v, &g);
+	 }
+	 if(a){
+		bigint_copy(a, &c_);
+	 }
+	 if(b){
+		 bigint_copy(b, &d_);
+	 }
+}
+
+/******************************************************************************/
+
+void bigint_inverse(bigint_t* dest, const bigint_t* a, const bigint_t* m){
+	bigint_gcdext(NULL, dest, NULL, a, m);
+	while(dest->info&BIGINT_NEG_MASK){
+		bigint_add_s(dest, dest, m);
+	}
+}
+
+/******************************************************************************/
+
+void bigint_changeendianess(bigint_t* a){
+	uint8_t t, *p, *q;
+	p = a->wordv;
+	q = p+a->length_B-1;
+	while(p<q){
+		t = *p;
+		*p = *q;
+		*q = t;
+		++p; --q;
+	}
+}
+
+/******************************************************************************/
+
+
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+