1// Copyright (c) 2013 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "crypto/curve25519.h"
6
7// Curve25519 is specified in terms of byte strings, not numbers, so all
8// implementations take and return the same sequence of bits. So the byte
9// order is implicitly specified as in, say, SHA1.
10//
11// Prototype for |curve25519_donna| function in
12// third_party/curve25519-donna/curve25519-donna.c
13extern "C" int curve25519_donna(uint8*, const uint8*, const uint8*);
14
15namespace crypto {
16
17namespace curve25519 {
18
19void ScalarMult(const uint8* private_key,
20                const uint8* peer_public_key,
21                uint8* shared_key) {
22  curve25519_donna(shared_key, private_key, peer_public_key);
23}
24
25// kBasePoint is the base point (generator) of the elliptic curve group.
26// It is little-endian version of '9' followed by 31 zeros.
27// See "Computing public keys" section of http://cr.yp.to/ecdh.html.
28static const unsigned char kBasePoint[32] = {9};
29
30void ScalarBaseMult(const uint8* private_key, uint8* public_key) {
31  curve25519_donna(public_key, private_key, kBasePoint);
32}
33
34}  // namespace curve25519
35
36}  // namespace crypto
37