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Merge pull request #4011 from lukechampine/chacha20poly1305 

crypto: Implement ChaCha20-Poly1305 AEAD (fixed)
master
Andrew Kelley 2019-12-30 17:39:46 -05:00 committed by GitHub
parent c70a673c6e ab093228f9
commit 34b4538d7b
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 203 additions and 0 deletions
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203
lib/std/crypto/chacha20.zig
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@ -7,6 +7,7 @@ const assert = std.debug.assert;
const testing = std.testing;
const builtin = @import("builtin");
const maxInt = std.math.maxInt;
const Poly1305 = std.crypto.Poly1305;
const QuarterRound = struct {
a: usize,
@ -434,3 +435,205 @@ test "crypto.chacha20 test vector 5" {
chaCha20With64BitNonce(result[0..], input[0..], 0, key, nonce);
testing.expectEqualSlices(u8, &expected_result, &result);
}
pub const chacha20poly1305_tag_size = 16;
pub fn chacha20poly1305Seal(dst: []u8, plaintext: []const u8, data: []const u8, key: [32]u8, nonce: [12]u8) void {
assert(dst.len >= plaintext.len + chacha20poly1305_tag_size);
// derive poly1305 key
var polyKey = [_]u8{0} ** 32;
chaCha20IETF(polyKey[0..], polyKey[0..], 0, key, nonce);
// encrypt plaintext
chaCha20IETF(dst[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(dst[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.writeIntSliceLittle(u64, lens[0..8], data.len);
mem.writeIntSliceLittle(u64, lens[8..16], plaintext.len);
mac.update(lens[0..]);
mac.final(dst[plaintext.len..]);
}
/// Verifies and decrypts an authenticated message produced by chacha20poly1305Seal.
pub fn chacha20poly1305Open(dst: []u8, msgAndTag: []const u8, data: []const u8, key: [32]u8, nonce: [12]u8) !void {
if (msgAndTag.len < chacha20poly1305_tag_size) {
return error.InvalidMessage;
}
// split ciphertext and tag
assert(dst.len >= msgAndTag.len - chacha20poly1305_tag_size);
var ciphertext = msgAndTag[0 .. msgAndTag.len - chacha20poly1305_tag_size];
var polyTag = msgAndTag[ciphertext.len..];
// derive poly1305 key
var polyKey = [_]u8{0} ** 32;
chaCha20IETF(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.writeIntSliceLittle(u64, lens[0..8], data.len);
mem.writeIntSliceLittle(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] ^ polyTag[i]);
}
if (acc != 0) {
return error.AuthenticationFailed;
}
// decrypt ciphertext
chaCha20IETF(dst[0..ciphertext.len], ciphertext, 1, key, 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));
}
}