bigint looks good but needs more testing (gcdext fixed)

[arm-crypto-lib.git] / bigint / bigint.c

diff --git a/bigint/bigint.c b/bigint/bigint.c
index c133faae826a538325d101f25d6fcdabd3f0e02d..6b76c188a399d00ae6dbeb8ed757415178541815 100644 (file)
--- a/bigint/bigint.c
+++ b/bigint/bigint.c
@@ -381,7 +381,7 @@ void bigint_shiftright(bigint_t* a, uint16_t shift){
                t |= ((bigint_wordplus_t)(a->wordv[0]))<<(BIGINT_WORD_SIZE-bitshift);
                a->wordv[0] = (bigint_word_t)(t>>BIGINT_WORD_SIZE);
        }
-       a->length_B -= ((shift/8)+sizeof(bigint_word_t)-1)/sizeof(bigint_word_t);
+    a->length_B -= ((shift/8)+sizeof(bigint_word_t)-1)/sizeof(bigint_word_t);
        bigint_adjust(a);
 }
 
@@ -574,12 +574,6 @@ void bigint_square(bigint_t* dest, const bigint_t* a){
 }
 
 /******************************************************************************/
-
-#define cli_putstr(a)
-#define bigint_print_hex(a)
-#define cli_hexdump_rev(a,b)
-#define uart_flush(a)
-
 void bigint_sub_u_bitscale(bigint_t* a, const bigint_t* b, uint16_t bitscale){
        bigint_t tmp;
        bigint_word_t tmp_b[b->length_B+4];
@@ -595,7 +589,7 @@ void bigint_sub_u_bitscale(bigint_t* a, const bigint_t* b, uint16_t bitscale){
        tmp.wordv = tmp_b;
        bigint_copy(&tmp, b);
        bigint_shiftleft(&tmp, bitscale&(BIGINT_WORD_SIZE-1));
-       cli_putstr("\r\nDBG(sub_ub.0) tmp_shift    = "); bigint_print_hex(&tmp);
+//     cli_putstr("\r\nDBG(sub_ub.0) tmp_shift    = "); bigint_print_hex(&tmp);
        for(j=0,i=word_shift; i<tmp.length_B+word_shift; ++i, ++j){
                t = a->wordv[i];
                t -= tmp.wordv[j];
@@ -628,7 +622,7 @@ void bigint_reduce(bigint_t* a, const bigint_t* r){
 //     bigint_adjust(r);
        uint8_t rfbs = GET_FBS(r);
 
-       cli_putstr("\r\nDBG: (a) = "); bigint_print_hex(a);
+//     cli_putstr("\r\nDBG: (a) = "); bigint_print_hex(a);
        if(r->length_B==0 || a->length_B==0){
                return;
        }
@@ -639,30 +633,30 @@ void bigint_reduce(bigint_t* a, const bigint_t* r){
                p %= q;
                memcpy(a->wordv, &p, a->length_B*sizeof(bigint_word_t));
                bigint_adjust(a);
-               cli_putstr("\r\nDBG: (0) = "); bigint_print_hex(a);
+//             cli_putstr("\r\nDBG: (0) = "); bigint_print_hex(a);
                return;
        }
        uint16_t shift;
        while(a->length_B > r->length_B){
                shift = (a->length_B-r->length_B)*8*sizeof(bigint_word_t)+GET_FBS(a)-rfbs-1;
-               cli_putstr("\r\nDBG: (p) shift = "); cli_hexdump_rev(&shift, 2);
-               uart_flush(0);
+//             cli_putstr("\r\nDBG: (p) shift = "); cli_hexdump_rev(&shift, 2);
+//             uart_flush(0);
                bigint_sub_u_bitscale(a, r, shift);
-               cli_putstr("\r\nDBG: (1) = "); bigint_print_hex(a);
+//             cli_putstr("\r\nDBG: (1) = "); bigint_print_hex(a);
        }
        while((GET_FBS(a) > rfbs+1) && (a->length_B == r->length_B)){
                shift = GET_FBS(a)-rfbs-1;
-               cli_putstr("\r\nDBG: (q) shift = "); cli_hexdump_rev(&shift, 2);
+//             cli_putstr("\r\nDBG: (q) shift = "); cli_hexdump_rev(&shift, 2);
                bigint_sub_u_bitscale(a, r, GET_FBS(a)-rfbs-1);
-               cli_putstr("\r\nDBG: (2) = "); bigint_print_hex(a);
+//             cli_putstr("\r\nDBG: (2) = "); bigint_print_hex(a);
        }
        while(bigint_cmp_u(a,r)>=0){
                bigint_sub_u(a,a,r);
-               cli_putstr("\r\nDBG: (3) = "); bigint_print_hex(a);
+//             cli_putstr("\r\nDBG: (3) = "); bigint_print_hex(a);
        }
        bigint_adjust(a);
-       cli_putstr("\r\nDBG: (a) = "); bigint_print_hex(a);
-       cli_putstr("\r\n");
+//     cli_putstr("\r\nDBG: (a) = "); bigint_print_hex(a);
+//     cli_putstr("\r\n");
 }
 
 /******************************************************************************/
@@ -713,13 +707,48 @@ void bigint_expmod_u(bigint_t* dest, const bigint_t* a, const bigint_t* exp, con
 }
 
 /******************************************************************************/
+
+#define cli_putstr(a)
+#define bigint_print_hex(a)
+#define cli_hexdump_rev(a,b)
+#define uart_flush(a)
+
 /* 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;
+        uint16_t i=0;
         if(x->length_B==0 || y->length_B==0){
                 return;
         }
+        if(x->length_B==1 && x->wordv[0]==1){
+                gcd->length_B = 1;
+                gcd->wordv[0] = 1;
+                if(a){
+                        a->length_B = 1;
+                        a->wordv[0] = 1;
+                        SET_POS(a);
+                        bigint_adjust(a);
+                }
+                if(b){
+                        bigint_set_zero(b);
+                }
+                return;
+        }
+        if(y->length_B==1 && y->wordv[0]==1){
+                gcd->length_B = 1;
+                gcd->wordv[0] = 1;
+                if(b){
+                        b->length_B = 1;
+                        b->wordv[0] = 1;
+                        SET_POS(b);
+                        bigint_adjust(b);
+                }
+                if(a){
+                        bigint_set_zero(a);
+                }
+                return;
+        }
+
         while(x->wordv[i]==0 && y->wordv[i]==0){
                 ++i;
         }
@@ -731,7 +760,7 @@ void bigint_gcdext(bigint_t* gcd, bigint_t* a, bigint_t* b, const bigint_t* x, c
         g.wordv = g_b;
         x_.wordv = x_b;
         y_.wordv = y_b;
-        memset(g_b, 0, i);
+        memset(g_b, 0, i*sizeof(bigint_word_t));
         g_b[i]=1;
         g.length_B = i+1;
         g.info=0;
@@ -751,6 +780,7 @@ void bigint_gcdext(bigint_t* gcd, bigint_t* a, bigint_t* b, const bigint_t* x, c
                 bigint_shiftright(&x_, i);
                 bigint_shiftright(&y_, i);
         }
+
         u.wordv = u_b;
         v.wordv = v_b;
         a_.wordv = a_b;
@@ -769,7 +799,9 @@ void bigint_gcdext(bigint_t* gcd, bigint_t* a, bigint_t* b, const bigint_t* x, c
         bigint_set_zero(&b_);
         bigint_set_zero(&c_);
         do{
+                cli_putstr("\r\nDBG (gcdext) 0");
                 while((u.wordv[0]&1)==0){
+                        cli_putstr("\r\nDBG (gcdext) 0.1");
                         bigint_shiftright(&u, 1);
                         if((a_.wordv[0]&1) || (b_.wordv[0]&1)){
                                 bigint_add_s(&a_, &a_, &y_);
@@ -779,6 +811,7 @@ void bigint_gcdext(bigint_t* gcd, bigint_t* a, bigint_t* b, const bigint_t* x, c
                         bigint_shiftright(&b_, 1);
                 }
                 while((v.wordv[0]&1)==0){
+                        cli_putstr("\r\nDBG (gcdext) 0.2");
                         bigint_shiftright(&v, 1);
                         if((c_.wordv[0]&1) || (d_.wordv[0]&1)){
                                 bigint_add_s(&c_, &c_, &y_);