New "i62" code for big integers with 64x64->128 opcodes; also improved "i31" modular...

[BearSSL] / src / ec / ec_prime_i31.c

diff --git a/src/ec/ec_prime_i31.c b/src/ec/ec_prime_i31.c
index 440641e..ce4d4ab 100644 (file)
--- a/src/ec/ec_prime_i31.c
+++ b/src/ec/ec_prime_i31.c
@@ -135,7 +135,7 @@ typedef struct {
 
 /*
  * We use a custom interpreter that uses a dozen registers, and
 
 /*
  * We use a custom interpreter that uses a dozen registers, and

- * only four operations:
+ * only six operations:

  *    MSET(d, a)       copy a into d
  *    MADD(d, a)       d = d+a (modular)
  *    MSUB(d, a)       d = d-a (modular)
  *    MSET(d, a)       copy a into d
  *    MADD(d, a)       d = d+a (modular)
  *    MSUB(d, a)       d = d-a (modular)


@@ -717,6 +717,14 @@ api_order(int curve, size_t *len)
        return cd->order;
 }
 
        return cd->order;
 }
 

+static size_t
+api_xoff(int curve, size_t *len)
+{
+       api_generator(curve, len);
+       *len >>= 1;
+       return 1;
+}
+

 static uint32_t
 api_mul(unsigned char *G, size_t Glen,
        const unsigned char *x, size_t xlen, int curve)
 static uint32_t
 api_mul(unsigned char *G, size_t Glen,
        const unsigned char *x, size_t xlen, int curve)


@@ -732,6 +740,19 @@ api_mul(unsigned char *G, size_t Glen,
        return r;
 }
 
        return r;
 }
 

+static size_t
+api_mulgen(unsigned char *R,
+       const unsigned char *x, size_t xlen, int curve)
+{
+       const unsigned char *G;
+       size_t Glen;
+
+       G = api_generator(curve, &Glen);
+       memcpy(R, G, Glen);
+       api_mul(R, Glen, x, xlen, curve);
+       return Glen;
+}
+

 static uint32_t
 api_muladd(unsigned char *A, const unsigned char *B, size_t len,
        const unsigned char *x, size_t xlen,
 static uint32_t
 api_muladd(unsigned char *A, const unsigned char *B, size_t len,
        const unsigned char *x, size_t xlen,


@@ -749,6 +770,11 @@ api_muladd(unsigned char *A, const unsigned char *B, size_t len,
 
        cc = id_to_curve(curve);
        r = point_decode(&P, A, len, cc);
 
        cc = id_to_curve(curve);
        r = point_decode(&P, A, len, cc);

+       if (B == NULL) {
+               size_t Glen;
+
+               B = api_generator(curve, &Glen);
+       }

        r &= point_decode(&Q, B, len, cc);
        point_mul(&P, x, xlen, cc);
        point_mul(&Q, y, ylen, cc);
        r &= point_decode(&Q, B, len, cc);
        point_mul(&P, x, xlen, cc);
        point_mul(&Q, y, ylen, cc);


@@ -786,6 +812,8 @@ const br_ec_impl br_ec_prime_i31 = {
        (uint32_t)0x03800000,
        &api_generator,
        &api_order,
        (uint32_t)0x03800000,
        &api_generator,
        &api_order,

+       &api_xoff,

        &api_mul,
        &api_mul,

+       &api_mulgen,

        &api_muladd
 };
        &api_muladd
 };