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zig/lib/std/crypto/chacha20.zig
LemonBoy cd7c870bd8 std: Deprecate 'x'/'X'/'e'/'E' special cases for u8 slices 
Let's follow the road paved by the removal of 'z'/'Z', the Formatter
pattern is nice enough to let us remove the remaining four special cases
and declare u8 slices free from any special casing!
2021-03-01 15:33:10 -08:00

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// SPDX-License-Identifier: MIT
// Copyright (c) 2015-2021 Zig Contributors
// This file is part of [zig](https://ziglang.org/), which is MIT licensed.
// The MIT license requires this copyright notice to be included in all copies
// and substantial portions of the software.
// Based on public domain Supercop by Daniel J. Bernstein
const std = @import("../std.zig");
const math = std.math;
const mem = std.mem;
const assert = std.debug.assert;
const testing = std.testing;
const maxInt = math.maxInt;
const Vector = std.meta.Vector;
const Poly1305 = std.crypto.onetimeauth.Poly1305;
// Vectorized implementation of the core function
const ChaCha20VecImpl = struct {
const Lane = Vector(4, u32);
const BlockVec = [4]Lane;
fn initContext(key: [8]u32, d: [4]u32) BlockVec {
const c = "expand 32-byte k";
const constant_le = comptime Lane{
mem.readIntLittle(u32, c[0..4]),
mem.readIntLittle(u32, c[4..8]),
mem.readIntLittle(u32, c[8..12]),
mem.readIntLittle(u32, c[12..16]),
};
return BlockVec{
constant_le,
Lane{ key[0], key[1], key[2], key[3] },
Lane{ key[4], key[5], key[6], key[7] },
Lane{ d[0], d[1], d[2], d[3] },
};
}
fn chacha20Core(x: *BlockVec, input: BlockVec) callconv(.Inline) void {
x.* = input;
var r: usize = 0;
while (r < 20) : (r += 2) {
x[0] +%= x[1];
x[3] ^= x[0];
x[3] = math.rotl(Lane, x[3], 16);
x[2] +%= x[3];
x[1] ^= x[2];
x[1] = math.rotl(Lane, x[1], 12);
x[0] +%= x[1];
x[3] ^= x[0];
x[0] = @shuffle(u32, x[0], undefined, [_]i32{ 3, 0, 1, 2 });
x[3] = math.rotl(Lane, x[3], 8);
x[2] +%= x[3];
x[3] = @shuffle(u32, x[3], undefined, [_]i32{ 2, 3, 0, 1 });
x[1] ^= x[2];
x[2] = @shuffle(u32, x[2], undefined, [_]i32{ 1, 2, 3, 0 });
x[1] = math.rotl(Lane, x[1], 7);
x[0] +%= x[1];
x[3] ^= x[0];
x[3] = math.rotl(Lane, x[3], 16);
x[2] +%= x[3];
x[1] ^= x[2];
x[1] = math.rotl(Lane, x[1], 12);
x[0] +%= x[1];
x[3] ^= x[0];
x[0] = @shuffle(u32, x[0], undefined, [_]i32{ 1, 2, 3, 0 });
x[3] = math.rotl(Lane, x[3], 8);
x[2] +%= x[3];
x[3] = @shuffle(u32, x[3], undefined, [_]i32{ 2, 3, 0, 1 });
x[1] ^= x[2];
x[2] = @shuffle(u32, x[2], undefined, [_]i32{ 3, 0, 1, 2 });
x[1] = math.rotl(Lane, x[1], 7);
}
}
fn hashToBytes(out: *[64]u8, x: BlockVec) callconv(.Inline) void {
var i: usize = 0;
while (i < 4) : (i += 1) {
mem.writeIntLittle(u32, out[16 * i + 0 ..][0..4], x[i][0]);
mem.writeIntLittle(u32, out[16 * i + 4 ..][0..4], x[i][1]);
mem.writeIntLittle(u32, out[16 * i + 8 ..][0..4], x[i][2]);
mem.writeIntLittle(u32, out[16 * i + 12 ..][0..4], x[i][3]);
}
}
fn contextFeedback(x: *BlockVec, ctx: BlockVec) callconv(.Inline) void {
x[0] +%= ctx[0];
x[1] +%= ctx[1];
x[2] +%= ctx[2];
x[3] +%= ctx[3];
}
fn chacha20Xor(out: []u8, in: []const u8, key: [8]u32, counter: [4]u32) void {
var ctx = initContext(key, counter);
var x: BlockVec = undefined;
var buf: [64]u8 = undefined;
var i: usize = 0;
while (i + 64 <= in.len) : (i += 64) {
chacha20Core(x[0..], ctx);
contextFeedback(&x, ctx);
hashToBytes(buf[0..], x);
var xout = out[i..];
const xin = in[i..];
var j: usize = 0;
while (j < 64) : (j += 1) {
xout[j] = xin[j];
}
j = 0;
while (j < 64) : (j += 1) {
xout[j] ^= buf[j];
}
ctx[3][0] += 1;
}
if (i < in.len) {
chacha20Core(x[0..], ctx);
contextFeedback(&x, ctx);
hashToBytes(buf[0..], x);
var xout = out[i..];
const xin = in[i..];
var j: usize = 0;
while (j < in.len % 64) : (j += 1) {
xout[j] = xin[j] ^ buf[j];
}
}
}
fn hchacha20(input: [16]u8, key: [32]u8) [32]u8 {
var c: [4]u32 = undefined;
for (c) |_, i| {
c[i] = mem.readIntLittle(u32, input[4 * i ..][0..4]);
}
const ctx = initContext(keyToWords(key), c);
var x: BlockVec = undefined;
chacha20Core(x[0..], ctx);
var out: [32]u8 = undefined;
mem.writeIntLittle(u32, out[0..4], x[0][0]);
mem.writeIntLittle(u32, out[4..8], x[0][1]);
mem.writeIntLittle(u32, out[8..12], x[0][2]);
mem.writeIntLittle(u32, out[12..16], x[0][3]);
mem.writeIntLittle(u32, out[16..20], x[3][0]);
mem.writeIntLittle(u32, out[20..24], x[3][1]);
mem.writeIntLittle(u32, out[24..28], x[3][2]);
mem.writeIntLittle(u32, out[28..32], x[3][3]);
return out;
}
};
// Non-vectorized implementation of the core function
const ChaCha20NonVecImpl = struct {
const BlockVec = [16]u32;
fn initContext(key: [8]u32, d: [4]u32) BlockVec {
const c = "expand 32-byte k";
const constant_le = comptime [4]u32{
mem.readIntLittle(u32, c[0..4]),
mem.readIntLittle(u32, c[4..8]),
mem.readIntLittle(u32, c[8..12]),
mem.readIntLittle(u32, c[12..16]),
};
return BlockVec{
constant_le[0], constant_le[1], constant_le[2], constant_le[3],
key[0], key[1], key[2], key[3],
key[4], key[5], key[6], key[7],
d[0], d[1], d[2], d[3],
};
}
const QuarterRound = struct {
a: usize,
b: usize,
c: usize,
d: usize,
};
fn Rp(a: usize, b: usize, c: usize, d: usize) QuarterRound {
return QuarterRound{
.a = a,
.b = b,
.c = c,
.d = d,
};
}
fn chacha20Core(x: *BlockVec, input: BlockVec) callconv(.Inline) void {
x.* = input;
const rounds = comptime [_]QuarterRound{
Rp(0, 4, 8, 12),
Rp(1, 5, 9, 13),
Rp(2, 6, 10, 14),
Rp(3, 7, 11, 15),
Rp(0, 5, 10, 15),
Rp(1, 6, 11, 12),
Rp(2, 7, 8, 13),
Rp(3, 4, 9, 14),
};
comptime var j: usize = 0;
inline while (j < 20) : (j += 2) {
inline for (rounds) |r| {
x[r.a] +%= x[r.b];
x[r.d] = math.rotl(u32, x[r.d] ^ x[r.a], @as(u32, 16));
x[r.c] +%= x[r.d];
x[r.b] = math.rotl(u32, x[r.b] ^ x[r.c], @as(u32, 12));
x[r.a] +%= x[r.b];
x[r.d] = math.rotl(u32, x[r.d] ^ x[r.a], @as(u32, 8));
x[r.c] +%= x[r.d];
x[r.b] = math.rotl(u32, x[r.b] ^ x[r.c], @as(u32, 7));
}
}
}
fn hashToBytes(out: *[64]u8, x: BlockVec) callconv(.Inline) void {
var i: usize = 0;
while (i < 4) : (i += 1) {
mem.writeIntLittle(u32, out[16 * i + 0 ..][0..4], x[i * 4 + 0]);
mem.writeIntLittle(u32, out[16 * i + 4 ..][0..4], x[i * 4 + 1]);
mem.writeIntLittle(u32, out[16 * i + 8 ..][0..4], x[i * 4 + 2]);
mem.writeIntLittle(u32, out[16 * i + 12 ..][0..4], x[i * 4 + 3]);
}
}
fn contextFeedback(x: *BlockVec, ctx: BlockVec) callconv(.Inline) void {
var i: usize = 0;
while (i < 16) : (i += 1) {
x[i] +%= ctx[i];
}
}
fn chacha20Xor(out: []u8, in: []const u8, key: [8]u32, counter: [4]u32) void {
var ctx = initContext(key, counter);
var x: BlockVec = undefined;
var buf: [64]u8 = undefined;
var i: usize = 0;
while (i + 64 <= in.len) : (i += 64) {
chacha20Core(x[0..], ctx);
contextFeedback(&x, ctx);
hashToBytes(buf[0..], x);
var xout = out[i..];
const xin = in[i..];
var j: usize = 0;
while (j < 64) : (j += 1) {
xout[j] = xin[j];
}
j = 0;
while (j < 64) : (j += 1) {
xout[j] ^= buf[j];
}
ctx[12] += 1;
}
if (i < in.len) {
chacha20Core(x[0..], ctx);
contextFeedback(&x, ctx);
hashToBytes(buf[0..], x);
var xout = out[i..];
const xin = in[i..];
var j: usize = 0;
while (j < in.len % 64) : (j += 1) {
xout[j] = xin[j] ^ buf[j];
}
}
}
fn hchacha20(input: [16]u8, key: [32]u8) [32]u8 {
var c: [4]u32 = undefined;
for (c) |_, i| {
c[i] = mem.readIntLittle(u32, input[4 * i ..][0..4]);
}
const ctx = initContext(keyToWords(key), c);
var x: BlockVec = undefined;
chacha20Core(x[0..], ctx);
var out: [32]u8 = undefined;
mem.writeIntLittle(u32, out[0..4], x[0]);
mem.writeIntLittle(u32, out[4..8], x[1]);
mem.writeIntLittle(u32, out[8..12], x[2]);
mem.writeIntLittle(u32, out[12..16], x[3]);
mem.writeIntLittle(u32, out[16..20], x[12]);
mem.writeIntLittle(u32, out[20..24], x[13]);
mem.writeIntLittle(u32, out[24..28], x[14]);
mem.writeIntLittle(u32, out[28..32], x[15]);
return out;
}
};
const ChaCha20Impl = if (std.Target.current.cpu.arch == .x86_64) ChaCha20VecImpl else ChaCha20NonVecImpl;
fn keyToWords(key: [32]u8) [8]u32 {
var k: [8]u32 = undefined;
var i: usize = 0;
while (i < 8) : (i += 1) {
k[i] = mem.readIntLittle(u32, key[i * 4 ..][0..4]);
}
return k;
}
/// ChaCha20 avoids the possibility of timing attacks, as there are no branches
/// on secret key data.
///
/// in and out should be the same length.
/// counter should generally be 0 or 1
///
/// ChaCha20 is self-reversing. To decrypt just run the cipher with the same
/// counter, nonce, and key.
pub const ChaCha20IETF = struct {
pub fn xor(out: []u8, in: []const u8, counter: u32, key: [32]u8, nonce: [12]u8) void {
assert(in.len == out.len);
assert((in.len >> 6) + counter <= maxInt(u32));
var c: [4]u32 = undefined;
c[0] = counter;
c[1] = mem.readIntLittle(u32, nonce[0..4]);
c[2] = mem.readIntLittle(u32, nonce[4..8]);
c[3] = mem.readIntLittle(u32, nonce[8..12]);
ChaCha20Impl.chacha20Xor(out, in, keyToWords(key), c);
}
};
/// This is the original ChaCha20 before RFC 7539, which recommends using the
/// orgininal version on applications such as disk or file encryption that might
/// exceed the 256 GiB limit of the 96-bit nonce version.
pub const ChaCha20With64BitNonce = struct {
pub fn xor(out: []u8, in: []const u8, counter: u64, key: [32]u8, nonce: [8]u8) void {
assert(in.len == out.len);
assert(counter +% (in.len >> 6) >= counter);
var cursor: usize = 0;
const k = keyToWords(key);
var c: [4]u32 = undefined;
c[0] = @truncate(u32, counter);
c[1] = @truncate(u32, counter >> 32);
c[2] = mem.readIntLittle(u32, nonce[0..4]);
c[3] = mem.readIntLittle(u32, nonce[4..8]);
const block_length = (1 << 6);
// The full block size is greater than the address space on a 32bit machine
const big_block = if (@sizeOf(usize) > 4) (block_length << 32) else maxInt(usize);
// first partial big block
if (((@intCast(u64, maxInt(u32) - @truncate(u32, counter)) + 1) << 6) < in.len) {
ChaCha20Impl.chacha20Xor(out[cursor..big_block], in[cursor..big_block], k, c);
cursor = big_block - cursor;
c[1] += 1;
if (comptime @sizeOf(usize) > 4) {
// A big block is giant: 256 GiB, but we can avoid this limitation
var remaining_blocks: u32 = @intCast(u32, (in.len / big_block));
var i: u32 = 0;
while (remaining_blocks > 0) : (remaining_blocks -= 1) {
ChaCha20Impl.chacha20Xor(out[cursor .. cursor + big_block], in[cursor .. cursor + big_block], k, c);
c[1] += 1; // upper 32-bit of counter, generic chacha20Xor() doesn't know about this.
cursor += big_block;
}
}
}
ChaCha20Impl.chacha20Xor(out[cursor..], in[cursor..], k, c);
}
};
// https://tools.ietf.org/html/rfc7539#section-2.4.2
test "crypto.chacha20 test vector sunscreen" {
const expected_result = [_]u8{
0x6e, 0x2e, 0x35, 0x9a, 0x25, 0x68, 0xf9, 0x80,
0x41, 0xba, 0x07, 0x28, 0xdd, 0x0d, 0x69, 0x81,
0xe9, 0x7e, 0x7a, 0xec, 0x1d, 0x43, 0x60, 0xc2,
0x0a, 0x27, 0xaf, 0xcc, 0xfd, 0x9f, 0xae, 0x0b,
0xf9, 0x1b, 0x65, 0xc5, 0x52, 0x47, 0x33, 0xab,
0x8f, 0x59, 0x3d, 0xab, 0xcd, 0x62, 0xb3, 0x57,
0x16, 0x39, 0xd6, 0x24, 0xe6, 0x51, 0x52, 0xab,
0x8f, 0x53, 0x0c, 0x35, 0x9f, 0x08, 0x61, 0xd8,
0x07, 0xca, 0x0d, 0xbf, 0x50, 0x0d, 0x6a, 0x61,
0x56, 0xa3, 0x8e, 0x08, 0x8a, 0x22, 0xb6, 0x5e,
0x52, 0xbc, 0x51, 0x4d, 0x16, 0xcc, 0xf8, 0x06,
0x81, 0x8c, 0xe9, 0x1a, 0xb7, 0x79, 0x37, 0x36,
0x5a, 0xf9, 0x0b, 0xbf, 0x74, 0xa3, 0x5b, 0xe6,
0xb4, 0x0b, 0x8e, 0xed, 0xf2, 0x78, 0x5e, 0x42,
0x87, 0x4d,
};
const input = "Ladies and Gentlemen of the class of '99: If I could offer you only one tip for the future, sunscreen would be it.";
var result: [114]u8 = undefined;
const key = [_]u8{
0, 1, 2, 3, 4, 5, 6, 7,
8, 9, 10, 11, 12, 13, 14, 15,
16, 17, 18, 19, 20, 21, 22, 23,
24, 25, 26, 27, 28, 29, 30, 31,
};
const nonce = [_]u8{
0, 0, 0, 0,
0, 0, 0, 0x4a,
0, 0, 0, 0,
};
ChaCha20IETF.xor(result[0..], input[0..], 1, key, nonce);
testing.expectEqualSlices(u8, &expected_result, &result);
// Chacha20 is self-reversing.
var plaintext: [114]u8 = undefined;
ChaCha20IETF.xor(plaintext[0..], result[0..], 1, key, nonce);
testing.expect(mem.order(u8, input, &plaintext) == .eq);
}
// https://tools.ietf.org/html/draft-agl-tls-chacha20poly1305-04#section-7
test "crypto.chacha20 test vector 1" {
const expected_result = [_]u8{
0x76, 0xb8, 0xe0, 0xad, 0xa0, 0xf1, 0x3d, 0x90,
0x40, 0x5d, 0x6a, 0xe5, 0x53, 0x86, 0xbd, 0x28,
0xbd, 0xd2, 0x19, 0xb8, 0xa0, 0x8d, 0xed, 0x1a,
0xa8, 0x36, 0xef, 0xcc, 0x8b, 0x77, 0x0d, 0xc7,
0xda, 0x41, 0x59, 0x7c, 0x51, 0x57, 0x48, 0x8d,
0x77, 0x24, 0xe0, 0x3f, 0xb8, 0xd8, 0x4a, 0x37,
0x6a, 0x43, 0xb8, 0xf4, 0x15, 0x18, 0xa1, 0x1c,
0xc3, 0x87, 0xb6, 0x69, 0xb2, 0xee, 0x65, 0x86,
};
const input = [_]u8{
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
};
var result: [64]u8 = undefined;
const key = [_]u8{
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
};
const nonce = [_]u8{ 0, 0, 0, 0, 0, 0, 0, 0 };
ChaCha20With64BitNonce.xor(result[0..], input[0..], 0, key, nonce);
testing.expectEqualSlices(u8, &expected_result, &result);
}
test "crypto.chacha20 test vector 2" {
const expected_result = [_]u8{
0x45, 0x40, 0xf0, 0x5a, 0x9f, 0x1f, 0xb2, 0x96,
0xd7, 0x73, 0x6e, 0x7b, 0x20, 0x8e, 0x3c, 0x96,
0xeb, 0x4f, 0xe1, 0x83, 0x46, 0x88, 0xd2, 0x60,
0x4f, 0x45, 0x09, 0x52, 0xed, 0x43, 0x2d, 0x41,
0xbb, 0xe2, 0xa0, 0xb6, 0xea, 0x75, 0x66, 0xd2,
0xa5, 0xd1, 0xe7, 0xe2, 0x0d, 0x42, 0xaf, 0x2c,
0x53, 0xd7, 0x92, 0xb1, 0xc4, 0x3f, 0xea, 0x81,
0x7e, 0x9a, 0xd2, 0x75, 0xae, 0x54, 0x69, 0x63,
};
const input = [_]u8{
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
};
var result: [64]u8 = undefined;
const key = [_]u8{
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 1,
};
const nonce = [_]u8{ 0, 0, 0, 0, 0, 0, 0, 0 };
ChaCha20With64BitNonce.xor(result[0..], input[0..], 0, key, nonce);
testing.expectEqualSlices(u8, &expected_result, &result);
}
test "crypto.chacha20 test vector 3" {
const expected_result = [_]u8{
0xde, 0x9c, 0xba, 0x7b, 0xf3, 0xd6, 0x9e, 0xf5,
0xe7, 0x86, 0xdc, 0x63, 0x97, 0x3f, 0x65, 0x3a,
0x0b, 0x49, 0xe0, 0x15, 0xad, 0xbf, 0xf7, 0x13,
0x4f, 0xcb, 0x7d, 0xf1, 0x37, 0x82, 0x10, 0x31,
0xe8, 0x5a, 0x05, 0x02, 0x78, 0xa7, 0x08, 0x45,
0x27, 0x21, 0x4f, 0x73, 0xef, 0xc7, 0xfa, 0x5b,
0x52, 0x77, 0x06, 0x2e, 0xb7, 0xa0, 0x43, 0x3e,
0x44, 0x5f, 0x41, 0xe3,
};
const input = [_]u8{
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
};
var result: [60]u8 = undefined;
const key = [_]u8{
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
};
const nonce = [_]u8{ 0, 0, 0, 0, 0, 0, 0, 1 };
ChaCha20With64BitNonce.xor(result[0..], input[0..], 0, key, nonce);
testing.expectEqualSlices(u8, &expected_result, &result);
}
test "crypto.chacha20 test vector 4" {
const expected_result = [_]u8{
0xef, 0x3f, 0xdf, 0xd6, 0xc6, 0x15, 0x78, 0xfb,
0xf5, 0xcf, 0x35, 0xbd, 0x3d, 0xd3, 0x3b, 0x80,
0x09, 0x63, 0x16, 0x34, 0xd2, 0x1e, 0x42, 0xac,
0x33, 0x96, 0x0b, 0xd1, 0x38, 0xe5, 0x0d, 0x32,
0x11, 0x1e, 0x4c, 0xaf, 0x23, 0x7e, 0xe5, 0x3c,
0xa8, 0xad, 0x64, 0x26, 0x19, 0x4a, 0x88, 0x54,
0x5d, 0xdc, 0x49, 0x7a, 0x0b, 0x46, 0x6e, 0x7d,
0x6b, 0xbd, 0xb0, 0x04, 0x1b, 0x2f, 0x58, 0x6b,
};
const input = [_]u8{
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
};
var result: [64]u8 = undefined;
const key = [_]u8{
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
};
const nonce = [_]u8{ 1, 0, 0, 0, 0, 0, 0, 0 };
ChaCha20With64BitNonce.xor(result[0..], input[0..], 0, key, nonce);
testing.expectEqualSlices(u8, &expected_result, &result);
}
test "crypto.chacha20 test vector 5" {
const expected_result = [_]u8{
0xf7, 0x98, 0xa1, 0x89, 0xf1, 0x95, 0xe6, 0x69,
0x82, 0x10, 0x5f, 0xfb, 0x64, 0x0b, 0xb7, 0x75,
0x7f, 0x57, 0x9d, 0xa3, 0x16, 0x02, 0xfc, 0x93,
0xec, 0x01, 0xac, 0x56, 0xf8, 0x5a, 0xc3, 0xc1,
0x34, 0xa4, 0x54, 0x7b, 0x73, 0x3b, 0x46, 0x41,
0x30, 0x42, 0xc9, 0x44, 0x00, 0x49, 0x17, 0x69,
0x05, 0xd3, 0xbe, 0x59, 0xea, 0x1c, 0x53, 0xf1,
0x59, 0x16, 0x15, 0x5c, 0x2b, 0xe8, 0x24, 0x1a,
0x38, 0x00, 0x8b, 0x9a, 0x26, 0xbc, 0x35, 0x94,
0x1e, 0x24, 0x44, 0x17, 0x7c, 0x8a, 0xde, 0x66,
0x89, 0xde, 0x95, 0x26, 0x49, 0x86, 0xd9, 0x58,
0x89, 0xfb, 0x60, 0xe8, 0x46, 0x29, 0xc9, 0xbd,
0x9a, 0x5a, 0xcb, 0x1c, 0xc1, 0x18, 0xbe, 0x56,
0x3e, 0xb9, 0xb3, 0xa4, 0xa4, 0x72, 0xf8, 0x2e,
0x09, 0xa7, 0xe7, 0x78, 0x49, 0x2b, 0x56, 0x2e,
0xf7, 0x13, 0x0e, 0x88, 0xdf, 0xe0, 0x31, 0xc7,
0x9d, 0xb9, 0xd4, 0xf7, 0xc7, 0xa8, 0x99, 0x15,
0x1b, 0x9a, 0x47, 0x50, 0x32, 0xb6, 0x3f, 0xc3,
0x85, 0x24, 0x5f, 0xe0, 0x54, 0xe3, 0xdd, 0x5a,
0x97, 0xa5, 0xf5, 0x76, 0xfe, 0x06, 0x40, 0x25,
0xd3, 0xce, 0x04, 0x2c, 0x56, 0x6a, 0xb2, 0xc5,
0x07, 0xb1, 0x38, 0xdb, 0x85, 0x3e, 0x3d, 0x69,
0x59, 0x66, 0x09, 0x96, 0x54, 0x6c, 0xc9, 0xc4,
0xa6, 0xea, 0xfd, 0xc7, 0x77, 0xc0, 0x40, 0xd7,
0x0e, 0xaf, 0x46, 0xf7, 0x6d, 0xad, 0x39, 0x79,
0xe5, 0xc5, 0x36, 0x0c, 0x33, 0x17, 0x16, 0x6a,
0x1c, 0x89, 0x4c, 0x94, 0xa3, 0x71, 0x87, 0x6a,
0x94, 0xdf, 0x76, 0x28, 0xfe, 0x4e, 0xaa, 0xf2,
0xcc, 0xb2, 0x7d, 0x5a, 0xaa, 0xe0, 0xad, 0x7a,
0xd0, 0xf9, 0xd4, 0xb6, 0xad, 0x3b, 0x54, 0x09,
0x87, 0x46, 0xd4, 0x52, 0x4d, 0x38, 0x40, 0x7a,
0x6d, 0xeb, 0x3a, 0xb7, 0x8f, 0xab, 0x78, 0xc9,
};
const input = [_]u8{
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
};
var result: [256]u8 = undefined;
const key = [_]u8{
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
};
const nonce = [_]u8{
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
};
ChaCha20With64BitNonce.xor(result[0..], input[0..], 0, key, nonce);
testing.expectEqualSlices(u8, &expected_result, &result);
}
pub const chacha20poly1305_tag_length = 16;
fn chacha20poly1305SealDetached(ciphertext: []u8, tag: *[chacha20poly1305_tag_length]u8, plaintext: []const u8, data: []const u8, key: [32]u8, nonce: [12]u8) void {
assert(ciphertext.len == plaintext.len);
// derive poly1305 key
var polyKey = [_]u8{0} ** 32;
ChaCha20IETF.xor(polyKey[0..], polyKey[0..], 0, key, nonce);
// encrypt plaintext
ChaCha20IETF.xor(ciphertext[0..plaintext.len], plaintext, 1, key, nonce);
// construct mac
var mac = Poly1305.init(polyKey[0..]);
mac.update(data);
if (data.len % 16 != 0) {
const zeros = [_]u8{0} ** 16;
const padding = 16 - (data.len % 16);
mac.update(zeros[0..padding]);
}
mac.update(ciphertext[0..plaintext.len]);
if (plaintext.len % 16 != 0) {
const zeros = [_]u8{0} ** 16;
const padding = 16 - (plaintext.len % 16);
mac.update(zeros[0..padding]);
}
var lens: [16]u8 = undefined;
mem.writeIntLittle(u64, lens[0..8], data.len);
mem.writeIntLittle(u64, lens[8..16], plaintext.len);
mac.update(lens[0..]);
mac.final(tag);
}
fn chacha20poly1305Seal(ciphertextAndTag: []u8, plaintext: []const u8, data: []const u8, key: [32]u8, nonce: [12]u8) void {
return chacha20poly1305SealDetached(ciphertextAndTag[0..plaintext.len], ciphertextAndTag[plaintext.len..][0..chacha20poly1305_tag_length], plaintext, data, key, nonce);
}
/// Verifies and decrypts an authenticated message produced by chacha20poly1305SealDetached.
fn chacha20poly1305OpenDetached(dst: []u8, ciphertext: []const u8, tag: *const [chacha20poly1305_tag_length]u8, data: []const u8, key: [32]u8, nonce: [12]u8) !void {
// split ciphertext and tag
assert(dst.len == ciphertext.len);
// derive poly1305 key
var polyKey = [_]u8{0} ** 32;
ChaCha20IETF.xor(polyKey[0..], polyKey[0..], 0, key, nonce);
// construct mac
var mac = Poly1305.init(polyKey[0..]);
mac.update(data);
if (data.len % 16 != 0) {
const zeros = [_]u8{0} ** 16;
const padding = 16 - (data.len % 16);
mac.update(zeros[0..padding]);
}
mac.update(ciphertext);
if (ciphertext.len % 16 != 0) {
const zeros = [_]u8{0} ** 16;
const padding = 16 - (ciphertext.len % 16);
mac.update(zeros[0..padding]);
}
var lens: [16]u8 = undefined;
mem.writeIntLittle(u64, lens[0..8], data.len);
mem.writeIntLittle(u64, lens[8..16], ciphertext.len);
mac.update(lens[0..]);
var computedTag: [16]u8 = undefined;
mac.final(computedTag[0..]);
// verify mac in constant time
// TODO: we can't currently guarantee that this will run in constant time.
// See https://github.com/ziglang/zig/issues/1776
var acc: u8 = 0;
for (computedTag) |_, i| {
acc |= computedTag[i] ^ tag[i];
}
if (acc != 0) {
return error.AuthenticationFailed;
}
// decrypt ciphertext
ChaCha20IETF.xor(dst[0..ciphertext.len], ciphertext, 1, key, nonce);
}
/// Verifies and decrypts an authenticated message produced by chacha20poly1305Seal.
fn chacha20poly1305Open(dst: []u8, ciphertextAndTag: []const u8, data: []const u8, key: [32]u8, nonce: [12]u8) !void {
if (ciphertextAndTag.len < chacha20poly1305_tag_length) {
return error.InvalidMessage;
}
const ciphertextLen = ciphertextAndTag.len - chacha20poly1305_tag_length;
return try chacha20poly1305OpenDetached(dst, ciphertextAndTag[0..ciphertextLen], ciphertextAndTag[ciphertextLen..][0..chacha20poly1305_tag_length], data, key, nonce);
}
fn extend(key: [32]u8, nonce: [24]u8) struct { key: [32]u8, nonce: [12]u8 } {
var subnonce: [12]u8 = undefined;
mem.set(u8, subnonce[0..4], 0);
mem.copy(u8, subnonce[4..], nonce[16..24]);
return .{
.key = ChaCha20Impl.hchacha20(nonce[0..16].*, key),
.nonce = subnonce,
};
}
pub const XChaCha20IETF = struct {
pub fn xor(out: []u8, in: []const u8, counter: u32, key: [32]u8, nonce: [24]u8) void {
const extended = extend(key, nonce);
ChaCha20IETF.xor(out, in, counter, extended.key, extended.nonce);
}
};
pub const xchacha20poly1305_tag_length = 16;
fn xchacha20poly1305SealDetached(ciphertext: []u8, tag: *[chacha20poly1305_tag_length]u8, plaintext: []const u8, data: []const u8, key: [32]u8, nonce: [24]u8) void {
const extended = extend(key, nonce);
return chacha20poly1305SealDetached(ciphertext, tag, plaintext, data, extended.key, extended.nonce);
}
fn xchacha20poly1305Seal(ciphertextAndTag: []u8, plaintext: []const u8, data: []const u8, key: [32]u8, nonce: [24]u8) void {
const extended = extend(key, nonce);
return chacha20poly1305Seal(ciphertextAndTag, plaintext, data, extended.key, extended.nonce);
}
/// Verifies and decrypts an authenticated message produced by xchacha20poly1305SealDetached.
fn xchacha20poly1305OpenDetached(plaintext: []u8, ciphertext: []const u8, tag: *const [chacha20poly1305_tag_length]u8, data: []const u8, key: [32]u8, nonce: [24]u8) !void {
const extended = extend(key, nonce);
return try chacha20poly1305OpenDetached(plaintext, ciphertext, tag, data, extended.key, extended.nonce);
}
/// Verifies and decrypts an authenticated message produced by xchacha20poly1305Seal.
fn xchacha20poly1305Open(ciphertextAndTag: []u8, msgAndTag: []const u8, data: []const u8, key: [32]u8, nonce: [24]u8) !void {
const extended = extend(key, nonce);
return try chacha20poly1305Open(ciphertextAndTag, msgAndTag, data, extended.key, extended.nonce);
}
test "seal" {
{
const plaintext = "";
const data = "";
const key = [_]u8{
0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
};
const nonce = [_]u8{ 0x7, 0x0, 0x0, 0x0, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47 };
const exp_out = [_]u8{ 0xa0, 0x78, 0x4d, 0x7a, 0x47, 0x16, 0xf3, 0xfe, 0xb4, 0xf6, 0x4e, 0x7f, 0x4b, 0x39, 0xbf, 0x4 };
var out: [exp_out.len]u8 = undefined;
chacha20poly1305Seal(out[0..], plaintext, data, key, nonce);
testing.expectEqualSlices(u8, exp_out[0..], out[0..]);
}
{
const plaintext = [_]u8{
0x4c, 0x61, 0x64, 0x69, 0x65, 0x73, 0x20, 0x61, 0x6e, 0x64, 0x20, 0x47, 0x65, 0x6e, 0x74, 0x6c,
0x65, 0x6d, 0x65, 0x6e, 0x20, 0x6f, 0x66, 0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6c, 0x61, 0x73,
0x73, 0x20, 0x6f, 0x66, 0x20, 0x27, 0x39, 0x39, 0x3a, 0x20, 0x49, 0x66, 0x20, 0x49, 0x20, 0x63,
0x6f, 0x75, 0x6c, 0x64, 0x20, 0x6f, 0x66, 0x66, 0x65, 0x72, 0x20, 0x79, 0x6f, 0x75, 0x20, 0x6f,
0x6e, 0x6c, 0x79, 0x20, 0x6f, 0x6e, 0x65, 0x20, 0x74, 0x69, 0x70, 0x20, 0x66, 0x6f, 0x72, 0x20,
0x74, 0x68, 0x65, 0x20, 0x66, 0x75, 0x74, 0x75, 0x72, 0x65, 0x2c, 0x20, 0x73, 0x75, 0x6e, 0x73,
0x63, 0x72, 0x65, 0x65, 0x6e, 0x20, 0x77, 0x6f, 0x75, 0x6c, 0x64, 0x20, 0x62, 0x65, 0x20, 0x69,
0x74, 0x2e,
};
const data = [_]u8{ 0x50, 0x51, 0x52, 0x53, 0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7 };
const key = [_]u8{
0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
};
const nonce = [_]u8{ 0x7, 0x0, 0x0, 0x0, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47 };
const exp_out = [_]u8{
0xd3, 0x1a, 0x8d, 0x34, 0x64, 0x8e, 0x60, 0xdb, 0x7b, 0x86, 0xaf, 0xbc, 0x53, 0xef, 0x7e, 0xc2,
0xa4, 0xad, 0xed, 0x51, 0x29, 0x6e, 0x8, 0xfe, 0xa9, 0xe2, 0xb5, 0xa7, 0x36, 0xee, 0x62, 0xd6,
0x3d, 0xbe, 0xa4, 0x5e, 0x8c, 0xa9, 0x67, 0x12, 0x82, 0xfa, 0xfb, 0x69, 0xda, 0x92, 0x72, 0x8b,
0x1a, 0x71, 0xde, 0xa, 0x9e, 0x6, 0xb, 0x29, 0x5, 0xd6, 0xa5, 0xb6, 0x7e, 0xcd, 0x3b, 0x36,
0x92, 0xdd, 0xbd, 0x7f, 0x2d, 0x77, 0x8b, 0x8c, 0x98, 0x3, 0xae, 0xe3, 0x28, 0x9, 0x1b, 0x58,
0xfa, 0xb3, 0x24, 0xe4, 0xfa, 0xd6, 0x75, 0x94, 0x55, 0x85, 0x80, 0x8b, 0x48, 0x31, 0xd7, 0xbc,
0x3f, 0xf4, 0xde, 0xf0, 0x8e, 0x4b, 0x7a, 0x9d, 0xe5, 0x76, 0xd2, 0x65, 0x86, 0xce, 0xc6, 0x4b,
0x61, 0x16, 0x1a, 0xe1, 0xb, 0x59, 0x4f, 0x9, 0xe2, 0x6a, 0x7e, 0x90, 0x2e, 0xcb, 0xd0, 0x60,
0x6, 0x91,
};
var out: [exp_out.len]u8 = undefined;
chacha20poly1305Seal(out[0..], plaintext[0..], data[0..], key, nonce);
testing.expectEqualSlices(u8, exp_out[0..], out[0..]);
}
}
test "open" {
{
const ciphertext = [_]u8{ 0xa0, 0x78, 0x4d, 0x7a, 0x47, 0x16, 0xf3, 0xfe, 0xb4, 0xf6, 0x4e, 0x7f, 0x4b, 0x39, 0xbf, 0x4 };
const data = "";
const key = [_]u8{
0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
};
const nonce = [_]u8{ 0x7, 0x0, 0x0, 0x0, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47 };
const exp_out = "";
var out: [exp_out.len]u8 = undefined;
try chacha20poly1305Open(out[0..], ciphertext[0..], data, key, nonce);
testing.expectEqualSlices(u8, exp_out[0..], out[0..]);
}
{
const ciphertext = [_]u8{
0xd3, 0x1a, 0x8d, 0x34, 0x64, 0x8e, 0x60, 0xdb, 0x7b, 0x86, 0xaf, 0xbc, 0x53, 0xef, 0x7e, 0xc2,
0xa4, 0xad, 0xed, 0x51, 0x29, 0x6e, 0x8, 0xfe, 0xa9, 0xe2, 0xb5, 0xa7, 0x36, 0xee, 0x62, 0xd6,
0x3d, 0xbe, 0xa4, 0x5e, 0x8c, 0xa9, 0x67, 0x12, 0x82, 0xfa, 0xfb, 0x69, 0xda, 0x92, 0x72, 0x8b,
0x1a, 0x71, 0xde, 0xa, 0x9e, 0x6, 0xb, 0x29, 0x5, 0xd6, 0xa5, 0xb6, 0x7e, 0xcd, 0x3b, 0x36,
0x92, 0xdd, 0xbd, 0x7f, 0x2d, 0x77, 0x8b, 0x8c, 0x98, 0x3, 0xae, 0xe3, 0x28, 0x9, 0x1b, 0x58,
0xfa, 0xb3, 0x24, 0xe4, 0xfa, 0xd6, 0x75, 0x94, 0x55, 0x85, 0x80, 0x8b, 0x48, 0x31, 0xd7, 0xbc,
0x3f, 0xf4, 0xde, 0xf0, 0x8e, 0x4b, 0x7a, 0x9d, 0xe5, 0x76, 0xd2, 0x65, 0x86, 0xce, 0xc6, 0x4b,
0x61, 0x16, 0x1a, 0xe1, 0xb, 0x59, 0x4f, 0x9, 0xe2, 0x6a, 0x7e, 0x90, 0x2e, 0xcb, 0xd0, 0x60,
0x6, 0x91,
};
const data = [_]u8{ 0x50, 0x51, 0x52, 0x53, 0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7 };
const key = [_]u8{
0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
};
const nonce = [_]u8{ 0x7, 0x0, 0x0, 0x0, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47 };
const exp_out = [_]u8{
0x4c, 0x61, 0x64, 0x69, 0x65, 0x73, 0x20, 0x61, 0x6e, 0x64, 0x20, 0x47, 0x65, 0x6e, 0x74, 0x6c,
0x65, 0x6d, 0x65, 0x6e, 0x20, 0x6f, 0x66, 0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6c, 0x61, 0x73,
0x73, 0x20, 0x6f, 0x66, 0x20, 0x27, 0x39, 0x39, 0x3a, 0x20, 0x49, 0x66, 0x20, 0x49, 0x20, 0x63,
0x6f, 0x75, 0x6c, 0x64, 0x20, 0x6f, 0x66, 0x66, 0x65, 0x72, 0x20, 0x79, 0x6f, 0x75, 0x20, 0x6f,
0x6e, 0x6c, 0x79, 0x20, 0x6f, 0x6e, 0x65, 0x20, 0x74, 0x69, 0x70, 0x20, 0x66, 0x6f, 0x72, 0x20,
0x74, 0x68, 0x65, 0x20, 0x66, 0x75, 0x74, 0x75, 0x72, 0x65, 0x2c, 0x20, 0x73, 0x75, 0x6e, 0x73,
0x63, 0x72, 0x65, 0x65, 0x6e, 0x20, 0x77, 0x6f, 0x75, 0x6c, 0x64, 0x20, 0x62, 0x65, 0x20, 0x69,
0x74, 0x2e,
};
var out: [exp_out.len]u8 = undefined;
try chacha20poly1305Open(out[0..], ciphertext[0..], data[0..], key, nonce);
testing.expectEqualSlices(u8, exp_out[0..], out[0..]);
// corrupting the ciphertext, data, key, or nonce should cause a failure
var bad_ciphertext = ciphertext;
bad_ciphertext[0] ^= 1;
testing.expectError(error.AuthenticationFailed, chacha20poly1305Open(out[0..], bad_ciphertext[0..], data[0..], key, nonce));
var bad_data = data;
bad_data[0] ^= 1;
testing.expectError(error.AuthenticationFailed, chacha20poly1305Open(out[0..], ciphertext[0..], bad_data[0..], key, nonce));
var bad_key = key;
bad_key[0] ^= 1;
testing.expectError(error.AuthenticationFailed, chacha20poly1305Open(out[0..], ciphertext[0..], data[0..], bad_key, nonce));
var bad_nonce = nonce;
bad_nonce[0] ^= 1;
testing.expectError(error.AuthenticationFailed, chacha20poly1305Open(out[0..], ciphertext[0..], data[0..], key, bad_nonce));
// a short ciphertext should result in a different error
testing.expectError(error.InvalidMessage, chacha20poly1305Open(out[0..], "", data[0..], key, bad_nonce));
}
}
test "crypto.xchacha20" {
const key = [_]u8{69} ** 32;
const nonce = [_]u8{42} ** 24;
const input = "Ladies and Gentlemen of the class of '99: If I could offer you only one tip for the future, sunscreen would be it.";
{
var ciphertext: [input.len]u8 = undefined;
XChaCha20IETF.xor(ciphertext[0..], input[0..], 0, key, nonce);
var buf: [2 * ciphertext.len]u8 = undefined;
testing.expectEqualStrings(try std.fmt.bufPrint(&buf, "{s}", .{std.fmt.fmtSliceHexUpper(&ciphertext)}), "E0A1BCF939654AFDBDC1746EC49832647C19D891F0D1A81FC0C1703B4514BDEA584B512F6908C2C5E9DD18D5CBC1805DE5803FE3B9CA5F193FB8359E91FAB0C3BB40309A292EB1CF49685C65C4A3ADF4F11DB0CD2B6B67FBC174BC2E860E8F769FD3565BBFAD1C845E05A0FED9BE167C240D");
}
{
const data = "Additional data";
var ciphertext: [input.len + xchacha20poly1305_tag_length]u8 = undefined;
xchacha20poly1305Seal(ciphertext[0..], input, data, key, nonce);
var out: [input.len]u8 = undefined;
try xchacha20poly1305Open(out[0..], ciphertext[0..], data, key, nonce);
var buf: [2 * ciphertext.len]u8 = undefined;
testing.expectEqualStrings(try std.fmt.bufPrint(&buf, "{s}", .{std.fmt.fmtSliceHexUpper(&ciphertext)}), "994D2DD32333F48E53650C02C7A2ABB8E018B0836D7175AEC779F52E961780768F815C58F1AA52D211498DB89B9216763F569C9433A6BBFCEFB4D4A49387A4C5207FBB3B5A92B5941294DF30588C6740D39DC16FA1F0E634F7246CF7CDCB978E44347D89381B7A74EB7084F754B90BDE9AAF5A94B8F2A85EFD0B50692AE2D425E234");
testing.expectEqualSlices(u8, out[0..], input);
ciphertext[0] += 1;
testing.expectError(error.AuthenticationFailed, xchacha20poly1305Open(out[0..], ciphertext[0..], data, key, nonce));
}
}
pub const Chacha20Poly1305 = struct {
pub const tag_length = 16;
pub const nonce_length = 12;
pub const key_length = 32;
/// c: ciphertext: output buffer should be of size m.len
/// tag: authentication tag: output MAC
/// m: message
/// ad: Associated Data
/// npub: public nonce
/// k: private key
pub fn encrypt(c: []u8, tag: *[tag_length]u8, m: []const u8, ad: []const u8, npub: [nonce_length]u8, k: [key_length]u8) void {
assert(c.len == m.len);
return chacha20poly1305SealDetached(c, tag, m, ad, k, npub);
}
/// m: message: output buffer should be of size c.len
/// c: ciphertext
/// tag: authentication tag
/// ad: Associated Data
/// npub: public nonce
/// k: private key
/// NOTE: the check of the authentication tag is currently not done in constant time
pub fn decrypt(m: []u8, c: []const u8, tag: [tag_length]u8, ad: []const u8, npub: [nonce_length]u8, k: [key_length]u8) !void {
assert(c.len == m.len);
return try chacha20poly1305OpenDetached(m, c, tag[0..], ad, k, npub);
}
};
pub const XChacha20Poly1305 = struct {
pub const tag_length = 16;
pub const nonce_length = 24;
pub const key_length = 32;
/// c: ciphertext: output buffer should be of size m.len
/// tag: authentication tag: output MAC
/// m: message
/// ad: Associated Data
/// npub: public nonce
/// k: private key
pub fn encrypt(c: []u8, tag: *[tag_length]u8, m: []const u8, ad: []const u8, npub: [nonce_length]u8, k: [key_length]u8) void {
assert(c.len == m.len);
return xchacha20poly1305SealDetached(c, tag, m, ad, k, npub);
}
/// m: message: output buffer should be of size c.len
/// c: ciphertext
/// tag: authentication tag
/// ad: Associated Data
/// npub: public nonce
/// k: private key
/// NOTE: the check of the authentication tag is currently not done in constant time
pub fn decrypt(m: []u8, c: []const u8, tag: [tag_length]u8, ad: []const u8, npub: [nonce_length]u8, k: [key_length]u8) !void {
assert(c.len == m.len);
return try xchacha20poly1305OpenDetached(m, c, tag[0..], ad, k, npub);
}
};
test "chacha20 AEAD API" {
const aeads = [_]type{ Chacha20Poly1305, XChacha20Poly1305 };
const input = "Ladies and Gentlemen of the class of '99: If I could offer you only one tip for the future, sunscreen would be it.";
const data = "Additional data";
inline for (aeads) |aead| {
const key = [_]u8{69} ** aead.key_length;
const nonce = [_]u8{42} ** aead.nonce_length;
var ciphertext: [input.len]u8 = undefined;
var tag: [aead.tag_length]u8 = undefined;
var out: [input.len]u8 = undefined;
aead.encrypt(ciphertext[0..], tag[0..], input, data, nonce, key);
try aead.decrypt(out[0..], ciphertext[0..], tag, data[0..], nonce, key);
testing.expectEqualSlices(u8, out[0..], input);
ciphertext[0] += 1;
testing.expectError(error.AuthenticationFailed, aead.decrypt(out[0..], ciphertext[0..], tag, data[0..], nonce, key));
}
}
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