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Some renames, fix load function, add default base

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This commit is contained in:
Matthias Schiffer 2012-03-13 05:56:19 +01:00
parent b45baaba78
commit fb00f40057
2 changed files with 28 additions and 15 deletions
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19
include/libuecc/ecc.h
View file

@ -27,12 +27,6 @@
#ifndef _LIBUECC_ECC_H_
#define _LIBUECC_ECC_H_
typedef struct _ec_public_key_xyz_256_work {
unsigned int X[32];
unsigned int Y[32];
unsigned int Z[32];
} ec_public_key_xyz_256_work;
typedef struct _ec_public_key_256 {
unsigned char p[32];
} ec_public_key_256;
@ -41,16 +35,19 @@ typedef struct _ec_secret_key_256 {
unsigned char s[32];
} ec_secret_key_256;
typedef ec_public_key_xyz_256_work ec_25519_work;
typedef struct _ec_25519_work {
unsigned int X[32];
unsigned int Y[32];
unsigned int Z[32];
} ec_25519_work;
void ec_25519_inflate(ec_25519_work *out, const ec_public_key_256 *in);
void ec_25519_deflate(ec_public_key_256 *out, ec_25519_work *in);
void ec_25519_load(ec_25519_work *out, const ec_public_key_256 *in);
void ec_25519_store(ec_public_key_256 *out, const ec_25519_work *in);
void ec_25519_add(ec_25519_work *out, const ec_25519_work *in1, const ec_25519_work *in2);
void ec_25519_double(ec_25519_work *out, const ec_25519_work *in);
void ec_25519_scalarmult(ec_25519_work *out, const ec_secret_key_256 *n, const ec_25519_work *base);
void ec_25519_scalarmult_base(ec_25519_work *out, const ec_secret_key_256 *n);
#endif /* _LIBUECC_ECC_H_ */

24
src/ec25519.c
View file

@ -25,7 +25,7 @@
*/
/*
EC group operations for Twisted Edwards Curve ax^2 + y^2 + 1 + dx^2y^2 with
EC group operations for Twisted Edwards Curve ax^2 + y^2 = 1 + dx^2y^2 with
a = 486664
d = 486660
on prime field p = 2^255 - 19.
@ -340,7 +340,7 @@ static void recip(unsigned int out[32], const unsigned int z[32]) {
/* 2^255 - 21 */ mult(out, t1, z11);
}
void ec_25519_inflate(ec_25519_work *out, const ec_public_key_256 *in) {
void ec_25519_load(ec_25519_work *out, const ec_public_key_256 *in) {
int i;
unsigned int X2[32], d_X2[32] = {0x04, 0x6d, 0x07} /* 486660 */, a_X2[32] = {0x08, 0x6d, 0x07} /* 486664 */, _1_a_X2[32], d_X2_a_X2[32], Y[32], Yt[32];
@ -359,10 +359,10 @@ void ec_25519_inflate(ec_25519_work *out, const ec_public_key_256 *in) {
square_root(Y, d_X2_a_X2);
sub(Yt, zero, Y);
select(out->Y, Y, Yt, in->p[31] >> 7);
select(out->Y, Y, Yt, (in->p[31] >> 7) ^ (Y[0] & 1));
}
void ec_25519_deflate(ec_public_key_256 *out, ec_25519_work *in) {
void ec_25519_store(ec_public_key_256 *out, const ec_25519_work *in) {
unsigned int x[32], y[32], z[32];
int i;
@ -454,3 +454,19 @@ void ec_25519_scalarmult(ec_25519_work *out, const ec_secret_key_256 *n, const e
out->Z[i] = cur.Z[i];
}
}
static const ec_25519_work default_base = {
{0x51, 0x89, 0xfa, 0x46, 0xa0, 0xc0, 0x8b, 0x3d,
0x30, 0x60, 0xf1, 0x7d, 0x2a, 0xec, 0xcd, 0xf3,
0x24, 0x50, 0x96, 0x62, 0x21, 0xfc, 0xe6, 0x18,
0x14, 0xd6, 0x11, 0xf8, 0x11, 0x91, 0xa1, 0x03},
{0xf3, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x5f},
{1}
};
void ec_25519_scalarmult_base(ec_25519_work *out, const ec_secret_key_256 *n) {
ec_25519_scalarmult(out, n, &default_base);
}