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refactor cardano internal scalar functions

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This commit is contained in:
Pavol Rusnak 2018-09-05 12:59:37 +02:00
parent 9da140fbf8
commit 0d215161dc
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GPG Key ID: 91F3B339B9A02A3D
1 changed files with 11 additions and 26 deletions
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37
bip32.c
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@ -260,38 +260,23 @@ int hdnode_private_ckd(HDNode *inout, uint32_t i)
}
#if USE_CARDANO
/* sk1 is zl8 and contains only 29 bytes of active data,
* so it's not going to overflow when adding to sk2 */
void scalar_add_no_overflow(const uint8_t * sk1, const uint8_t * sk2, uint8_t * res)
static void scalar_multiply8(const uint8_t *src, int bytes, uint8_t *dst)
{
uint16_t r = 0; int i;
for (i = 0; i < 32; i++) {
r = (uint16_t) sk1[i] + (uint16_t) sk2[i] + r;
res[i] = (uint8_t) r;
r >>= 8;
}
}
static void multiply8(uint8_t *dst, uint8_t *src, int bytes)
{
int i;
uint8_t prev_acc = 0;
for (i = 0; i < bytes; i++) {
for (int i = 0; i < bytes; i++) {
dst[i] = (src[i] << 3) + (prev_acc & 0x7);
prev_acc = src[i] >> 5;
}
dst[bytes] = src[bytes-1] >> 5;
dst[bytes] = src[bytes - 1] >> 5;
}
static void add_256bits(uint8_t *dst, uint8_t *src1, uint8_t *src2)
static void scalar_add_256bits(const uint8_t *src1, const uint8_t *src2, uint8_t *dst)
{
int i; uint8_t carry = 0;
for (i = 0; i < 32; i++) {
uint8_t a = src1[i];
uint8_t b = src2[i];
uint16_t r = (uint16_t) a + (uint16_t) b + (uint16_t) carry;
uint16_t r = 0;
for (int i = 0; i < 32; i++) {
r = r + (uint16_t)src1[i] + (uint16_t)src2[i];
dst[i] = r & 0xff;
carry = (r >= 0x100) ? 1 : 0;
r >>= 8;
}
}
@ -332,12 +317,12 @@ int hdnode_private_ckd_cardano(HDNode *inout, uint32_t index)
memset(zl8, 0, 32);
/* get 8 * Zl */
multiply8(zl8, z, 28);
scalar_multiply8(z, 28, zl8);
/* Kl = 8*Zl + parent(K)l */
scalar_add_no_overflow(zl8, priv_key, res_key);
scalar_add_256bits(zl8, priv_key, res_key);
/* Kr = Zr + parent(K)r */
add_256bits(res_key + 32, z+32, priv_key+32);
scalar_add_256bits(z + 32, priv_key + 32, res_key + 32);
memcpy(inout->private_key, res_key, 32);
memcpy(inout->private_key_extension, res_key + 32, 32);