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clean up

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NIIBE Yutaka
2014-01-27 11:17:10 +09:00
parent 4b65ed1a5b
commit e18df3af6b
1 changed files with 21 additions and 22 deletions
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43
src/ec_p256.c
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@@ -236,7 +236,7 @@ const bn256 *Gy = precomputed_KG[0].y;
static int static int
get_v_k_i (const bn256 *K, int i) get_vk_i (const bn256 *K, int i)
{ {
uint32_t w0, w1, w2, w3; uint32_t w0, w1, w2, w3;
@@ -264,42 +264,42 @@ get_v_k_i (const bn256 *K, int i)
* Return 0 on success. * Return 0 on success.
*/ */
int int
compute_kG (ac *X, const bn256 *orig_K) compute_kG (ac *X, const bn256 *K)
{ {
uint8_t ki_si[64]; /* Lower 4-bit for ki which is v_k_i -1, msb is uint8_t index[64]; /* Lower 4-bit for index absolute value, msb is
for si (encoded as: 0 means 1, 1 means -1). */ for sign (encoded as: 0 means 1, 1 means -1). */
bn256 K[1]; bn256 K_dash[1];
jpc Q[1], tmp[1], *dst; jpc Q[1], tmp[1], *dst;
int i; int i;
int v_k_i_prev; int vk_i_prev;
uint32_t k_is_even = bn256_is_even (orig_K); uint32_t k_is_even = bn256_is_even (K);
bn256_sub_uint (K, orig_K, k_is_even); bn256_sub_uint (K_dash, K, k_is_even);
/* It keeps the condition: 1 <= K <= N - 2, and K is odd. */ /* It keeps the condition: 1 <= K <= N - 2, and K is odd. */
/* Fill ki_si. */ /* Fill index. */
v_k_i_prev = get_v_k_i (K, 0); vk_i_prev = get_vk_i (K_dash, 0);
ki_si[0] = v_k_i_prev - 1; index[0] = vk_i_prev - 1;
for (i = 1; i < 64; i++) for (i = 1; i < 64; i++)
{ {
int v_k_i, is_zero; int vk_i, is_zero;
v_k_i = get_v_k_i (K, i); vk_i = get_vk_i (K_dash, i);
is_zero = (v_k_i == 0); is_zero = (vk_i == 0);
ki_si[i-1] = (v_k_i_prev - 1) | (is_zero << 7); index[i-1] = (vk_i_prev - 1) | (is_zero << 7);
v_k_i_prev = (is_zero ? v_k_i_prev : v_k_i); vk_i_prev = (is_zero ? vk_i_prev : vk_i);
} }
ki_si[63] = v_k_i_prev - 1; index[63] = vk_i_prev - 1;
memset (Q->z, 0, sizeof (bn256)); /* infinity */ memset (Q->z, 0, sizeof (bn256)); /* infinity */
for (i = 31; i >= 0; i--) for (i = 31; i >= 0; i--)
{ {
jpc_double (Q, Q); jpc_double (Q, Q);
jpc_add_ac_signed (Q, Q, &precomputed_KG[ki_si[i]&0x0f], jpc_add_ac_signed (Q, Q, &precomputed_KG[index[i]&0x0f],
ki_si[i] >> 7); index[i] >> 7);
jpc_add_ac_signed (Q, Q, &precomputed_2E_KG[ki_si[i+32]&0x0f], jpc_add_ac_signed (Q, Q, &precomputed_2E_KG[index[i+32]&0x0f],
ki_si[i+32] >> 7); index[i+32] >> 7);
} }
dst = k_is_even ? Q : tmp; dst = k_is_even ? Q : tmp;
@@ -439,7 +439,6 @@ int
compute_kP (ac *X, const naf4_257 *NAF_K, const ac *P) compute_kP (ac *X, const naf4_257 *NAF_K, const ac *P)
{ {
int i; int i;
int q_is_infinite = 1;
jpc Q[1]; jpc Q[1];
ac P3[1], P5[1], P7[1]; ac P3[1], P5[1], P7[1];
const ac *p_Pi[4]; const ac *p_Pi[4];