1 // Copyright (c) 2022-present The Bitcoin Core developers
2 // Distributed under the MIT software license, see the accompanying
3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
4 5 #include <bench/bench.h>
6 #include <key.h>
7 #include <pubkey.h>
8 #include <random.h>
9 #include <span.h>
10 11 #include <algorithm>
12 #include <array>
13 #include <cstddef>
14 #include <span>
15 16 static void BIP324_ECDH(benchmark::Bench& bench)
17 {
18 ECC_Context ecc_context{};
19 FastRandomContext rng;
20 21 std::array<std::byte, 32> key_data;
22 std::array<std::byte, EllSwiftPubKey::size()> our_ellswift_data;
23 std::array<std::byte, EllSwiftPubKey::size()> their_ellswift_data;
24 25 rng.fillrand(key_data);
26 rng.fillrand(our_ellswift_data);
27 rng.fillrand(their_ellswift_data);
28 29 bench.batch(1).unit("ecdh").run([&] {
30 CKey key;
31 key.Set(key_data.data(), key_data.data() + 32, true);
32 EllSwiftPubKey our_ellswift(our_ellswift_data);
33 EllSwiftPubKey their_ellswift(their_ellswift_data);
34 35 auto ret = key.ComputeBIP324ECDHSecret(their_ellswift, our_ellswift, true);
36 37 // To make sure that the computation is not the same on every iteration (ellswift decoding
38 // is variable-time), distribute bytes from the shared secret over the 3 inputs. The most
39 // important one is their_ellswift, because that one is actually decoded, so it's given most
40 // bytes. The data is copied into the middle, so that both halves are affected:
41 // - Copy 8 bytes from the resulting shared secret into middle of the private key.
42 std::copy(ret.begin(), ret.begin() + 8, key_data.begin() + 12);
43 // - Copy 8 bytes from the resulting shared secret into the middle of our ellswift key.
44 std::copy(ret.begin() + 8, ret.begin() + 16, our_ellswift_data.begin() + 28);
45 // - Copy 16 bytes from the resulting shared secret into the middle of their ellswift key.
46 std::copy(ret.begin() + 16, ret.end(), their_ellswift_data.begin() + 24);
47 });
48 }
49 50 BENCHMARK(BIP324_ECDH);
51