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-rw-r--r--src/ec25519.c24
1 files changed, 20 insertions, 4 deletions
diff --git a/src/ec25519.c b/src/ec25519.c
index 25ed1f6..effbfc6 100644
--- a/src/ec25519.c
+++ b/src/ec25519.c
@@ -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);
+}