LibCrypto: Add curve x25519
This commit is contained in:
stelar7
Idan Horowitz
parent
5a94402b60
commit
4daa5622fe
Notes:
sideshowbarker
2024-07-17 18:36:20 +09:00
Author: https://github.com/stelar7 Commit: https://github.com/SerenityOS/serenity/commit/4daa5622fe Pull-request: https://github.com/SerenityOS/serenity/pull/12493 Reviewed-by: https://github.com/IdanHo Reviewed-by: https://github.com/alimpfard
5 changed files with 455 additions and 0 deletions
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@ -2,6 +2,7 @@ set(TEST_SOURCES
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TestAES.cpp
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TestBigInteger.cpp
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TestChecksum.cpp
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TestCurves.cpp
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TestHash.cpp
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TestHMAC.cpp
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TestRSA.cpp
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76
Tests/LibCrypto/TestCurves.cpp
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76
Tests/LibCrypto/TestCurves.cpp
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@ -0,0 +1,76 @@
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/*
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* Copyright (c) 2022, stelar7 <dudedbz@gmail.com>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/ByteBuffer.h>
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#include <LibCrypto/Curves/X25519.h>
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#include <LibTest/TestCase.h>
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TEST_CASE(test_x25519)
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{
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// https://datatracker.ietf.org/doc/html/rfc7748#section-6.1
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u8 alice_private_key_data[32] {
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0x77, 0x07, 0x6d, 0x0a, 0x73, 0x18, 0xa5, 0x7d,
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0x3c, 0x16, 0xc1, 0x72, 0x51, 0xb2, 0x66, 0x45,
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0xdf, 0x4c, 0x2f, 0x87, 0xeb, 0xc0, 0x99, 0x2a,
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0xb1, 0x77, 0xfb, 0xa5, 0x1d, 0xb9, 0x2c, 0x2a
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};
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u8 alice_public_key_data[32] {
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0x85, 0x20, 0xf0, 0x09, 0x89, 0x30, 0xa7, 0x54,
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0x74, 0x8b, 0x7d, 0xdc, 0xb4, 0x3e, 0xf7, 0x5a,
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0x0d, 0xbf, 0x3a, 0x0d, 0x26, 0x38, 0x1a, 0xf4,
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0xeb, 0xa4, 0xa9, 0x8e, 0xaa, 0x9b, 0x4e, 0x6a
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};
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u8 bob_private_key_data[32] {
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0x5d, 0xab, 0x08, 0x7e, 0x62, 0x4a, 0x8a, 0x4b,
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0x79, 0xe1, 0x7f, 0x8b, 0x83, 0x80, 0x0e, 0xe6,
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0x6f, 0x3b, 0xb1, 0x29, 0x26, 0x18, 0xb6, 0xfd,
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0x1c, 0x2f, 0x8b, 0x27, 0xff, 0x88, 0xe0, 0xeb
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};
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u8 bob_public_key_data[32] {
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0xde, 0x9e, 0xdb, 0x7d, 0x7b, 0x7d, 0xc1, 0xb4,
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0xd3, 0x5b, 0x61, 0xc2, 0xec, 0xe4, 0x35, 0x37,
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0x3f, 0x83, 0x43, 0xc8, 0x5b, 0x78, 0x67, 0x4d,
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0xad, 0xfc, 0x7e, 0x14, 0x6f, 0x88, 0x2b, 0x4f
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};
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u8 shared_secret_data[32] {
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0x4a, 0x5d, 0x9d, 0x5b, 0xa4, 0xce, 0x2d, 0xe1,
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0x72, 0x8e, 0x3b, 0xf4, 0x80, 0x35, 0x0f, 0x25,
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0xe0, 0x7e, 0x21, 0xc9, 0x47, 0xd1, 0x9e, 0x33,
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0x76, 0xf0, 0x9b, 0x3c, 0x1e, 0x16, 0x17, 0x42
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};
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u8 coordinate_data[32] {
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0x09, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
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};
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ReadonlyBytes coordinate { coordinate_data, 32 };
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ReadonlyBytes alice_public_key { alice_public_key_data, 32 };
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ReadonlyBytes alice_private_key { alice_private_key_data, 32 };
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ReadonlyBytes bob_public_key { bob_public_key_data, 32 };
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ReadonlyBytes bob_private_key { bob_private_key_data, 32 };
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ReadonlyBytes shared_secret { shared_secret_data, 32 };
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auto generated_alice_public = MUST(Crypto::Curves::X25519::compute_coordinate(alice_private_key, coordinate));
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EXPECT_EQ(alice_public_key, generated_alice_public);
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auto generated_bob_public = MUST(Crypto::Curves::X25519::compute_coordinate(bob_private_key, coordinate));
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EXPECT_EQ(bob_public_key, generated_bob_public);
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auto shared_alice = MUST(Crypto::Curves::X25519::compute_coordinate(alice_private_key, bob_public_key));
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EXPECT_EQ(shared_alice, shared_secret);
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auto shared_bob = MUST(Crypto::Curves::X25519::compute_coordinate(bob_private_key, alice_public_key));
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EXPECT_EQ(shared_bob, shared_secret);
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EXPECT_EQ(shared_alice, shared_bob);
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}
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@ -17,6 +17,7 @@ set(SOURCES
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Checksum/Adler32.cpp
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Checksum/CRC32.cpp
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Cipher/AES.cpp
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Curves/X25519.cpp
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Hash/MD5.cpp
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Hash/SHA1.cpp
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Hash/SHA2.cpp
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337
Userland/Libraries/LibCrypto/Curves/X25519.cpp
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337
Userland/Libraries/LibCrypto/Curves/X25519.cpp
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@ -0,0 +1,337 @@
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/*
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* Copyright (c) 2022, stelar7 <dudedbz@gmail.com>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/ByteReader.h>
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#include <AK/Endian.h>
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#include <LibCrypto/Curves/X25519.h>
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namespace Crypto::Curves {
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void X25519::import_state(u32* state, ReadonlyBytes data)
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{
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for (auto i = 0; i < X25519::WORDS; i++) {
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u32 value = ByteReader::load32(data.offset_pointer(sizeof(u32) * i));
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state[i] = AK::convert_between_host_and_little_endian(value);
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}
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}
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ErrorOr<ByteBuffer> X25519::export_state(u32* data)
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{
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auto buffer = TRY(ByteBuffer::create_uninitialized(X25519::BYTES));
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for (auto i = 0; i < X25519::WORDS; i++) {
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u32 value = AK::convert_between_host_and_little_endian(data[i]);
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ByteReader::store(buffer.offset_pointer(sizeof(u32) * i), value);
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}
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return buffer;
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}
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void X25519::select(u32* state, u32* a, u32* b, u32 condition)
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{
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// If B < (2^255 - 19) then R = B, else R = A
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u32 mask = condition - 1;
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for (auto i = 0; i < X25519::WORDS; i++) {
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state[i] = (a[i] & mask) | (b[i] & ~mask);
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}
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}
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void X25519::set(u32* state, u32 value)
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{
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state[0] = value;
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for (auto i = 1; i < X25519::WORDS; i++) {
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state[i] = 0;
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}
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}
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void X25519::copy(u32* state, u32* value)
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{
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for (auto i = 0; i < X25519::WORDS; i++) {
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state[i] = value[i];
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}
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}
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void X25519::conditional_swap(u32* first, u32* second, u32 condition)
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{
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u32 mask = ~condition + 1;
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for (auto i = 0; i < X25519::WORDS; i++) {
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u32 temp = mask & (first[i] ^ second[i]);
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first[i] ^= temp;
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second[i] ^= temp;
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}
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}
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void X25519::modular_multiply_single(u32* state, u32* first, u32 second)
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{
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// Compute R = (A * B) mod p
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u64 temp = 0;
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u32 output[X25519::WORDS];
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for (auto i = 0; i < X25519::WORDS; i++) {
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temp += (u64)first[i] * second;
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output[i] = temp & 0xFFFFFFFF;
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temp >>= 32;
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}
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// Reduce bit 256 (2^256 = 38 mod p)
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temp *= 38;
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// Reduce bit 255 (2^255 = 19 mod p)
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temp += (output[7] >> 31) * 19;
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// Mask the most significant bit
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output[7] &= 0x7FFFFFFF;
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// Fast modular reduction
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for (auto i = 0; i < X25519::WORDS; i++) {
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temp += output[i];
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output[i] = temp & 0xFFFFFFFF;
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temp >>= 32;
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}
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modular_reduce(state, output);
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}
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void X25519::modular_square(u32* state, u32* value)
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{
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// Compute R = (A ^ 2) mod p
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modular_multiply(state, value, value);
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}
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void X25519::modular_multiply(u32* state, u32* first, u32* second)
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{
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// Compute R = (A * B) mod p
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u64 temp = 0;
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u64 carry = 0;
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u32 output[X25519::WORDS * 2];
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// Comba's method
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for (auto i = 0; i < 16; i++) {
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if (i < X25519::WORDS) {
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for (auto j = 0; j <= i; j++) {
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temp += (u64)first[j] * second[i - j];
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carry += temp >> 32;
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temp &= 0xFFFFFFFF;
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}
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} else {
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for (auto j = i - 7; j < X25519::WORDS; j++) {
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temp += (u64)first[j] * second[i - j];
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carry += temp >> 32;
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temp &= 0xFFFFFFFF;
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}
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}
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output[i] = temp & 0xFFFFFFFF;
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temp = carry & 0xFFFFFFFF;
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carry >>= 32;
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}
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// Reduce bit 255 (2^255 = 19 mod p)
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temp = (output[7] >> 31) * 19;
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// Mask the most significant bit
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output[7] &= 0x7FFFFFFF;
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// Fast modular reduction 1st pass
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for (auto i = 0; i < X25519::WORDS; i++) {
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temp += output[i];
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temp += (u64)output[i + 8] * 38;
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output[i] = temp & 0xFFFFFFFF;
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temp >>= 32;
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}
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// Reduce bit 256 (2^256 = 38 mod p)
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temp *= 38;
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// Reduce bit 255 (2^255 = 19 mod p)
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temp += (output[7] >> 31) * 19;
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// Mask the most significant bit
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output[7] &= 0x7FFFFFFF;
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// Fast modular reduction 2nd pass
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for (auto i = 0; i < X25519::WORDS; i++) {
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temp += output[i];
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output[i] = temp & 0xFFFFFFFF;
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temp >>= 32;
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}
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modular_reduce(state, output);
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}
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void X25519::modular_add(u32* state, u32* first, u32* second)
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{
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// R = (A + B) mod p
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u64 temp = 0;
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for (auto i = 0; i < X25519::WORDS; i++) {
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temp += first[i];
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temp += second[i];
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state[i] = temp & 0xFFFFFFFF;
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temp >>= 32;
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}
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modular_reduce(state, state);
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}
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void X25519::modular_subtract(u32* state, u32* first, u32* second)
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{
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// R = (A - B) mod p
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i64 temp = -19;
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for (auto i = 0; i < X25519::WORDS; i++) {
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temp += first[i];
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temp -= second[i];
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state[i] = temp & 0xFFFFFFFF;
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temp >>= 32;
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}
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// Compute R = A + (2^255 - 19) - B
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state[7] += 0x80000000;
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modular_reduce(state, state);
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}
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void X25519::modular_reduce(u32* state, u32* data)
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{
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// R = A mod p
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u64 temp = 19;
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u32 other[X25519::WORDS];
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for (auto i = 0; i < X25519::WORDS; i++) {
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temp += data[i];
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other[i] = temp & 0xFFFFFFFF;
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temp >>= 32;
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}
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// Compute B = A - (2^255 - 19)
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other[7] -= 0x80000000;
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u32 mask = (other[7] & 0x80000000) >> 31;
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select(state, other, data, mask);
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}
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void X25519::to_power_of_2n(u32* state, u32* value, u8 n)
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{
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// compute R = (A ^ (2^n)) mod p
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modular_square(state, value);
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for (auto i = 1; i < n; i++) {
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modular_square(state, state);
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}
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}
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void X25519::modular_multiply_inverse(u32* state, u32* value)
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{
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// Compute R = A^-1 mod p
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u32 u[X25519::WORDS];
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u32 v[X25519::WORDS];
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// Fermat's little theorem
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modular_square(u, value);
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modular_multiply(u, u, value);
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modular_square(u, u);
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modular_multiply(v, u, value);
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to_power_of_2n(u, v, 3);
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modular_multiply(u, u, v);
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modular_square(u, u);
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modular_multiply(v, u, value);
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to_power_of_2n(u, v, 7);
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modular_multiply(u, u, v);
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modular_square(u, u);
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modular_multiply(v, u, value);
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to_power_of_2n(u, v, 15);
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modular_multiply(u, u, v);
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modular_square(u, u);
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modular_multiply(v, u, value);
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to_power_of_2n(u, v, 31);
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modular_multiply(v, u, v);
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to_power_of_2n(u, v, 62);
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modular_multiply(u, u, v);
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modular_square(u, u);
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modular_multiply(v, u, value);
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to_power_of_2n(u, v, 125);
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modular_multiply(u, u, v);
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modular_square(u, u);
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modular_square(u, u);
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modular_multiply(u, u, value);
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modular_square(u, u);
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modular_square(u, u);
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modular_multiply(u, u, value);
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modular_square(u, u);
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modular_multiply(state, u, value);
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}
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// https://datatracker.ietf.org/doc/html/rfc7748#section-5
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ErrorOr<ByteBuffer> X25519::compute_coordinate(ReadonlyBytes input_k, ReadonlyBytes input_u)
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{
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u32 k[X25519::WORDS] {};
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u32 u[X25519::WORDS] {};
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u32 x1[X25519::WORDS] {};
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u32 x2[X25519::WORDS] {};
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u32 z1[X25519::WORDS] {};
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u32 z2[X25519::WORDS] {};
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u32 t1[X25519::WORDS] {};
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u32 t2[X25519::WORDS] {};
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// Copy input to internal state
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import_state(k, input_k);
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// Set the three least significant bits of the first byte and the most significant bit of the last to zero,
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// set the second most significant bit of the last byte to 1
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k[0] &= 0xFFFFFFF8;
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k[7] &= 0x7FFFFFFF;
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k[7] |= 0x40000000;
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// Copy coordinate to internal state
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import_state(u, input_u);
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// mask the most significant bit in the final byte.
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u[7] &= 0x7FFFFFFF;
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// Implementations MUST accept non-canonical values and process them as
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// if they had been reduced modulo the field prime.
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modular_reduce(u, u);
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set(x1, 1);
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set(z1, 0);
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copy(x2, u);
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set(z2, 1);
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// Montgomery ladder
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u32 swap = 0;
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for (auto i = X25519::BITS - 1; i >= 0; i--) {
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u32 b = (k[i / X25519::BYTES] >> (i % X25519::BYTES)) & 1;
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conditional_swap(x1, x2, swap ^ b);
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conditional_swap(z1, z2, swap ^ b);
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swap = b;
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modular_add(t1, x2, z2);
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modular_subtract(x2, x2, z2);
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modular_add(z2, x1, z1);
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modular_subtract(x1, x1, z1);
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modular_multiply(t1, t1, x1);
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modular_multiply(x2, x2, z2);
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modular_square(z2, z2);
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modular_square(x1, x1);
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modular_subtract(t2, z2, x1);
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modular_multiply_single(z1, t2, A24);
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modular_add(z1, z1, x1);
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modular_multiply(z1, z1, t2);
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modular_multiply(x1, x1, z2);
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modular_subtract(z2, t1, x2);
|
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modular_square(z2, z2);
|
||||
modular_multiply(z2, z2, u);
|
||||
modular_add(x2, x2, t1);
|
||||
modular_square(x2, x2);
|
||||
}
|
||||
|
||||
conditional_swap(x1, x2, swap);
|
||||
conditional_swap(z1, z2, swap);
|
||||
|
||||
// Retrieve affine representation
|
||||
modular_multiply_inverse(u, z1);
|
||||
modular_multiply(u, u, x1);
|
||||
|
||||
// Encode state for export
|
||||
return export_state(u);
|
||||
}
|
||||
}
|
||||
40
Userland/Libraries/LibCrypto/Curves/X25519.h
Normal file
40
Userland/Libraries/LibCrypto/Curves/X25519.h
Normal file
|
|
@ -0,0 +1,40 @@
|
|||
/*
|
||||
* Copyright (c) 2022, stelar7 <dudedbz@gmail.com>
|
||||
*
|
||||
* SPDX-License-Identifier: BSD-2-Clause
|
||||
*/
|
||||
|
||||
#pragma once
|
||||
|
||||
#include <AK/ByteBuffer.h>
|
||||
|
||||
namespace Crypto::Curves {
|
||||
|
||||
class X25519 {
|
||||
|
||||
static constexpr u8 BITS = 255;
|
||||
static constexpr u8 BYTES = 32;
|
||||
static constexpr u8 WORDS = 8;
|
||||
static constexpr u32 A24 = 121666;
|
||||
|
||||
public:
|
||||
static ErrorOr<ByteBuffer> compute_coordinate(ReadonlyBytes a, ReadonlyBytes b);
|
||||
|
||||
private:
|
||||
static void import_state(u32* state, ReadonlyBytes data);
|
||||
static ErrorOr<ByteBuffer> export_state(u32* data);
|
||||
static void select(u32* state, u32* a, u32* b, u32 condition);
|
||||
static void set(u32* state, u32 value);
|
||||
static void copy(u32* state, u32* value);
|
||||
static void conditional_swap(u32* first, u32* second, u32 condition);
|
||||
static void modular_multiply_single(u32* state, u32* first, u32 second);
|
||||
static void modular_square(u32* state, u32* value);
|
||||
static void modular_multiply(u32* state, u32* first, u32* second);
|
||||
static void modular_add(u32* state, u32* first, u32* second);
|
||||
static void modular_subtract(u32* state, u32* first, u32* second);
|
||||
static void modular_reduce(u32* state, u32* data);
|
||||
static void to_power_of_2n(u32* state, u32* value, u8 n);
|
||||
static void modular_multiply_inverse(u32* state, u32* value);
|
||||
};
|
||||
|
||||
}
|
||||
Loading…
Add table
Reference in a new issue