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Prepare 64-bit implementation for p256

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This commit is contained in:
Olivier Chéron 2020-01-11 08:42:59 +01:00
parent f291bd08ef
commit f9a6a35ce3
2 changed files with 32 additions and 26 deletions
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53
cbits/p256/p256.c
View File

@ -40,14 +40,16 @@
#include "p256/p256.h"
const cryptonite_p256_int cryptonite_SECP256r1_n = // curve order
{{0xfc632551, 0xf3b9cac2, 0xa7179e84, 0xbce6faad, -1, -1, 0, -1}};
{{P256_LITERAL(0xfc632551, 0xf3b9cac2), P256_LITERAL(0xa7179e84, 0xbce6faad),
P256_LITERAL(-1, -1), P256_LITERAL(0, -1)}};
const cryptonite_p256_int cryptonite_SECP256r1_p = // curve field size
{{-1, -1, -1, 0, 0, 0, 1, -1 }};
{{P256_LITERAL(-1, -1), P256_LITERAL(-1, 0),
P256_LITERAL(0, 0), P256_LITERAL(1, -1) }};
const cryptonite_p256_int cryptonite_SECP256r1_b = // curve b
{{0x27d2604b, 0x3bce3c3e, 0xcc53b0f6, 0x651d06b0,
0x769886bc, 0xb3ebbd55, 0xaa3a93e7, 0x5ac635d8}};
{{P256_LITERAL(0x27d2604b, 0x3bce3c3e), P256_LITERAL(0xcc53b0f6, 0x651d06b0),
P256_LITERAL(0x769886bc, 0xb3ebbd55), P256_LITERAL(0xaa3a93e7, 0x5ac635d8)}};
void cryptonite_p256_init(cryptonite_p256_int* a) {
memset(a, 0, sizeof(*a));
@ -61,9 +63,10 @@ int cryptonite_p256_get_bit(const cryptonite_p256_int* scalar, int bit) {
}
int cryptonite_p256_is_zero(const cryptonite_p256_int* a) {
int i, result = 0;
cryptonite_p256_digit result = 0;
int i = 0;
for (i = 0; i < P256_NDIGITS; ++i) result |= P256_DIGIT(a, i);
return !result;
return result == 0;
}
// top, c[] += a[] * b
@ -229,7 +232,7 @@ static void cryptonite_p256_shr1(const cryptonite_p256_int* a, int highbit, cryp
P256_DIGIT(b, i) = accu;
}
P256_DIGIT(b, i) = (P256_DIGIT(a, i) >> 1) |
(highbit << (P256_BITSPERDIGIT - 1));
(((cryptonite_p256_sdigit) highbit) << (P256_BITSPERDIGIT - 1));
}
// Return -1, 0, 1 for a < b, a == b or a > b respectively.
@ -359,31 +362,32 @@ int cryptonite_p256_is_valid_point(const cryptonite_p256_int* x, const cryptonit
}
void cryptonite_p256_from_bin(const uint8_t src[P256_NBYTES], cryptonite_p256_int* dst) {
int i;
int i, n;
const uint8_t* p = &src[0];
for (i = P256_NDIGITS - 1; i >= 0; --i) {
P256_DIGIT(dst, i) =
(p[0] << 24) |
(p[1] << 16) |
(p[2] << 8) |
p[3];
p += 4;
cryptonite_p256_digit dig = 0;
n = P256_BITSPERDIGIT;
while (n > 0) {
n -= 8;
dig |= ((cryptonite_p256_digit) *(p++)) << n;
}
P256_DIGIT(dst, i) = dig;
}
}
void cryptonite_p256_to_bin(const cryptonite_p256_int* src, uint8_t dst[P256_NBYTES])
{
int i;
int i, n;
uint8_t* p = &dst[0];
for (i = P256_NDIGITS -1; i >= 0; --i) {
const cryptonite_p256_digit dig = P256_DIGIT(src, i);
p[0] = dig >> 24;
p[1] = dig >> 16;
p[2] = dig >> 8;
p[3] = dig;
p += 4;
n = P256_BITSPERDIGIT;
while (n > 0) {
n -= 8;
*(p++) = dig >> n;
}
}
}
@ -409,9 +413,6 @@ void cryptonite_p256e_modsub(const cryptonite_p256_int* MOD, const cryptonite_p2
addM(MOD, 0, P256_DIGITS(c), top);
}
// n' such as n * n' = -1 mod (2^32)
#define MONTGOMERY_FACTOR 0xEE00BC4F
#define NTH_DOUBLE_THEN_ADD(i, a, nth, b, out) \
cryptonite_p256e_montmul(a, a, out); \
for (i = 1; i < nth; i++) \
@ -419,8 +420,8 @@ void cryptonite_p256e_modsub(const cryptonite_p256_int* MOD, const cryptonite_p2
cryptonite_p256e_montmul(out, b, out);
const cryptonite_p256_int cryptonite_SECP256r1_r2 = // r^2 mod n
{{0xBE79EEA2, 0x83244C95, 0x49BD6FA6, 0x4699799C,
0x2B6BEC59, 0x2845B239, 0xF3D95620, 0x66E12D94}};
{{P256_LITERAL(0xBE79EEA2, 0x83244C95), P256_LITERAL(0x49BD6FA6, 0x4699799C),
P256_LITERAL(0x2B6BEC59, 0x2845B239), P256_LITERAL(0xF3D95620, 0x66E12D94)}};
const cryptonite_p256_int cryptonite_SECP256r1_one = {{1}};
@ -443,7 +444,7 @@ static void cryptonite_p256e_montmul(const cryptonite_p256_int* a, const crypton
}
accum[j] = chain;
mand = accum[0] * MONTGOMERY_FACTOR;
mand = accum[0] * P256_MONTGOMERY_FACTOR;
chain = 0;
mier = P256_DIGITS(&cryptonite_SECP256r1_n);
for (j=0; j<P256_NDIGITS; j++) {

5
cbits/p256/p256.h
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@ -40,6 +40,11 @@ extern "C" {
#define P256_NDIGITS 8
#define P256_NBYTES 32
// n' such as n * n' = -1 mod (2^32)
#define P256_MONTGOMERY_FACTOR 0xEE00BC4F
#define P256_LITERAL(lo,hi) (lo), (hi)
typedef int cryptonite_p256_err;
typedef uint32_t cryptonite_p256_digit;
typedef int32_t cryptonite_p256_sdigit;