Merge pull request #4011 from lukechampine/chacha20poly1305
crypto: Implement ChaCha20-Poly1305 AEAD (fixed)master
Andrew Kelley
GitHub
commit
34b4538d7b
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@ -7,6 +7,7 @@ const assert = std.debug.assert;
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const testing = std.testing;
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const testing = std.testing;
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const builtin = @import("builtin");
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const builtin = @import("builtin");
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const maxInt = std.math.maxInt;
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const maxInt = std.math.maxInt;
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const Poly1305 = std.crypto.Poly1305;
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const QuarterRound = struct {
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const QuarterRound = struct {
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a: usize,
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a: usize,
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@ -434,3 +435,205 @@ test "crypto.chacha20 test vector 5" {
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chaCha20With64BitNonce(result[0..], input[0..], 0, key, nonce);
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chaCha20With64BitNonce(result[0..], input[0..], 0, key, nonce);
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testing.expectEqualSlices(u8, &expected_result, &result);
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testing.expectEqualSlices(u8, &expected_result, &result);
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}
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}
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pub const chacha20poly1305_tag_size = 16;
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pub fn chacha20poly1305Seal(dst: []u8, plaintext: []const u8, data: []const u8, key: [32]u8, nonce: [12]u8) void {
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assert(dst.len >= plaintext.len + chacha20poly1305_tag_size);
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// derive poly1305 key
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var polyKey = [_]u8{0} ** 32;
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chaCha20IETF(polyKey[0..], polyKey[0..], 0, key, nonce);
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// encrypt plaintext
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chaCha20IETF(dst[0..plaintext.len], plaintext, 1, key, nonce);
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// construct mac
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var mac = Poly1305.init(polyKey[0..]);
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mac.update(data);
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if (data.len % 16 != 0) {
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const zeros = [_]u8{0} ** 16;
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const padding = 16 - (data.len % 16);
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mac.update(zeros[0..padding]);
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}
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mac.update(dst[0..plaintext.len]);
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if (plaintext.len % 16 != 0) {
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const zeros = [_]u8{0} ** 16;
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const padding = 16 - (plaintext.len % 16);
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mac.update(zeros[0..padding]);
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}
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var lens: [16]u8 = undefined;
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mem.writeIntSliceLittle(u64, lens[0..8], data.len);
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mem.writeIntSliceLittle(u64, lens[8..16], plaintext.len);
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mac.update(lens[0..]);
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mac.final(dst[plaintext.len..]);
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}
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/// Verifies and decrypts an authenticated message produced by chacha20poly1305Seal.
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pub fn chacha20poly1305Open(dst: []u8, msgAndTag: []const u8, data: []const u8, key: [32]u8, nonce: [12]u8) !void {
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if (msgAndTag.len < chacha20poly1305_tag_size) {
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return error.InvalidMessage;
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}
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// split ciphertext and tag
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assert(dst.len >= msgAndTag.len - chacha20poly1305_tag_size);
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var ciphertext = msgAndTag[0 .. msgAndTag.len - chacha20poly1305_tag_size];
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var polyTag = msgAndTag[ciphertext.len..];
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// derive poly1305 key
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var polyKey = [_]u8{0} ** 32;
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chaCha20IETF(polyKey[0..], polyKey[0..], 0, key, nonce);
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// construct mac
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var mac = Poly1305.init(polyKey[0..]);
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mac.update(data);
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if (data.len % 16 != 0) {
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const zeros = [_]u8{0} ** 16;
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const padding = 16 - (data.len % 16);
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mac.update(zeros[0..padding]);
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}
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mac.update(ciphertext);
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if (ciphertext.len % 16 != 0) {
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const zeros = [_]u8{0} ** 16;
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const padding = 16 - (ciphertext.len % 16);
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mac.update(zeros[0..padding]);
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}
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var lens: [16]u8 = undefined;
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mem.writeIntSliceLittle(u64, lens[0..8], data.len);
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mem.writeIntSliceLittle(u64, lens[8..16], ciphertext.len);
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mac.update(lens[0..]);
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var computedTag: [16]u8 = undefined;
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mac.final(computedTag[0..]);
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// verify mac in constant time
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// TODO: we can't currently guarantee that this will run in constant time.
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// See https://github.com/ziglang/zig/issues/1776
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var acc: u8 = 0;
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for (computedTag) |_, i| {
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acc |= (computedTag[i] ^ polyTag[i]);
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}
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if (acc != 0) {
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return error.AuthenticationFailed;
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}
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// decrypt ciphertext
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chaCha20IETF(dst[0..ciphertext.len], ciphertext, 1, key, nonce);
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}
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test "seal" {
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{
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const plaintext = "";
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const data = "";
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const key = [_]u8{
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0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
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0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
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};
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const nonce = [_]u8{ 0x7, 0x0, 0x0, 0x0, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47 };
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const exp_out = [_]u8{ 0xa0, 0x78, 0x4d, 0x7a, 0x47, 0x16, 0xf3, 0xfe, 0xb4, 0xf6, 0x4e, 0x7f, 0x4b, 0x39, 0xbf, 0x4 };
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var out: [exp_out.len]u8 = undefined;
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chacha20poly1305Seal(out[0..], plaintext, data, key, nonce);
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testing.expectEqualSlices(u8, exp_out[0..], out[0..]);
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}
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{
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const plaintext = [_]u8{
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0x4c, 0x61, 0x64, 0x69, 0x65, 0x73, 0x20, 0x61, 0x6e, 0x64, 0x20, 0x47, 0x65, 0x6e, 0x74, 0x6c,
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0x65, 0x6d, 0x65, 0x6e, 0x20, 0x6f, 0x66, 0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6c, 0x61, 0x73,
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0x73, 0x20, 0x6f, 0x66, 0x20, 0x27, 0x39, 0x39, 0x3a, 0x20, 0x49, 0x66, 0x20, 0x49, 0x20, 0x63,
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0x6f, 0x75, 0x6c, 0x64, 0x20, 0x6f, 0x66, 0x66, 0x65, 0x72, 0x20, 0x79, 0x6f, 0x75, 0x20, 0x6f,
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0x6e, 0x6c, 0x79, 0x20, 0x6f, 0x6e, 0x65, 0x20, 0x74, 0x69, 0x70, 0x20, 0x66, 0x6f, 0x72, 0x20,
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0x74, 0x68, 0x65, 0x20, 0x66, 0x75, 0x74, 0x75, 0x72, 0x65, 0x2c, 0x20, 0x73, 0x75, 0x6e, 0x73,
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0x63, 0x72, 0x65, 0x65, 0x6e, 0x20, 0x77, 0x6f, 0x75, 0x6c, 0x64, 0x20, 0x62, 0x65, 0x20, 0x69,
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0x74, 0x2e,
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};
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const data = [_]u8{ 0x50, 0x51, 0x52, 0x53, 0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7 };
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const key = [_]u8{
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0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
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0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
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};
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const nonce = [_]u8{ 0x7, 0x0, 0x0, 0x0, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47 };
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const exp_out = [_]u8{
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0xd3, 0x1a, 0x8d, 0x34, 0x64, 0x8e, 0x60, 0xdb, 0x7b, 0x86, 0xaf, 0xbc, 0x53, 0xef, 0x7e, 0xc2,
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0xa4, 0xad, 0xed, 0x51, 0x29, 0x6e, 0x8, 0xfe, 0xa9, 0xe2, 0xb5, 0xa7, 0x36, 0xee, 0x62, 0xd6,
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0x3d, 0xbe, 0xa4, 0x5e, 0x8c, 0xa9, 0x67, 0x12, 0x82, 0xfa, 0xfb, 0x69, 0xda, 0x92, 0x72, 0x8b,
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0x1a, 0x71, 0xde, 0xa, 0x9e, 0x6, 0xb, 0x29, 0x5, 0xd6, 0xa5, 0xb6, 0x7e, 0xcd, 0x3b, 0x36,
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0x92, 0xdd, 0xbd, 0x7f, 0x2d, 0x77, 0x8b, 0x8c, 0x98, 0x3, 0xae, 0xe3, 0x28, 0x9, 0x1b, 0x58,
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0xfa, 0xb3, 0x24, 0xe4, 0xfa, 0xd6, 0x75, 0x94, 0x55, 0x85, 0x80, 0x8b, 0x48, 0x31, 0xd7, 0xbc,
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0x3f, 0xf4, 0xde, 0xf0, 0x8e, 0x4b, 0x7a, 0x9d, 0xe5, 0x76, 0xd2, 0x65, 0x86, 0xce, 0xc6, 0x4b,
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0x61, 0x16, 0x1a, 0xe1, 0xb, 0x59, 0x4f, 0x9, 0xe2, 0x6a, 0x7e, 0x90, 0x2e, 0xcb, 0xd0, 0x60,
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0x6, 0x91,
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};
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var out: [exp_out.len]u8 = undefined;
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chacha20poly1305Seal(out[0..], plaintext[0..], data[0..], key, nonce);
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testing.expectEqualSlices(u8, exp_out[0..], out[0..]);
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}
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}
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test "open" {
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{
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const ciphertext = [_]u8{ 0xa0, 0x78, 0x4d, 0x7a, 0x47, 0x16, 0xf3, 0xfe, 0xb4, 0xf6, 0x4e, 0x7f, 0x4b, 0x39, 0xbf, 0x4 };
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const data = "";
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const key = [_]u8{
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0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
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0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
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};
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const nonce = [_]u8{ 0x7, 0x0, 0x0, 0x0, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47 };
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const exp_out = "";
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var out: [exp_out.len]u8 = undefined;
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try chacha20poly1305Open(out[0..], ciphertext[0..], data, key, nonce);
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testing.expectEqualSlices(u8, exp_out[0..], out[0..]);
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}
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{
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const ciphertext = [_]u8{
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0xd3, 0x1a, 0x8d, 0x34, 0x64, 0x8e, 0x60, 0xdb, 0x7b, 0x86, 0xaf, 0xbc, 0x53, 0xef, 0x7e, 0xc2,
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0xa4, 0xad, 0xed, 0x51, 0x29, 0x6e, 0x8, 0xfe, 0xa9, 0xe2, 0xb5, 0xa7, 0x36, 0xee, 0x62, 0xd6,
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0x3d, 0xbe, 0xa4, 0x5e, 0x8c, 0xa9, 0x67, 0x12, 0x82, 0xfa, 0xfb, 0x69, 0xda, 0x92, 0x72, 0x8b,
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0x1a, 0x71, 0xde, 0xa, 0x9e, 0x6, 0xb, 0x29, 0x5, 0xd6, 0xa5, 0xb6, 0x7e, 0xcd, 0x3b, 0x36,
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0x92, 0xdd, 0xbd, 0x7f, 0x2d, 0x77, 0x8b, 0x8c, 0x98, 0x3, 0xae, 0xe3, 0x28, 0x9, 0x1b, 0x58,
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0xfa, 0xb3, 0x24, 0xe4, 0xfa, 0xd6, 0x75, 0x94, 0x55, 0x85, 0x80, 0x8b, 0x48, 0x31, 0xd7, 0xbc,
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0x3f, 0xf4, 0xde, 0xf0, 0x8e, 0x4b, 0x7a, 0x9d, 0xe5, 0x76, 0xd2, 0x65, 0x86, 0xce, 0xc6, 0x4b,
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0x61, 0x16, 0x1a, 0xe1, 0xb, 0x59, 0x4f, 0x9, 0xe2, 0x6a, 0x7e, 0x90, 0x2e, 0xcb, 0xd0, 0x60,
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0x6, 0x91,
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};
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const data = [_]u8{ 0x50, 0x51, 0x52, 0x53, 0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7 };
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const key = [_]u8{
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0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
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0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
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};
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const nonce = [_]u8{ 0x7, 0x0, 0x0, 0x0, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47 };
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const exp_out = [_]u8{
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0x4c, 0x61, 0x64, 0x69, 0x65, 0x73, 0x20, 0x61, 0x6e, 0x64, 0x20, 0x47, 0x65, 0x6e, 0x74, 0x6c,
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0x65, 0x6d, 0x65, 0x6e, 0x20, 0x6f, 0x66, 0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6c, 0x61, 0x73,
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0x73, 0x20, 0x6f, 0x66, 0x20, 0x27, 0x39, 0x39, 0x3a, 0x20, 0x49, 0x66, 0x20, 0x49, 0x20, 0x63,
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0x6f, 0x75, 0x6c, 0x64, 0x20, 0x6f, 0x66, 0x66, 0x65, 0x72, 0x20, 0x79, 0x6f, 0x75, 0x20, 0x6f,
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0x6e, 0x6c, 0x79, 0x20, 0x6f, 0x6e, 0x65, 0x20, 0x74, 0x69, 0x70, 0x20, 0x66, 0x6f, 0x72, 0x20,
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0x74, 0x68, 0x65, 0x20, 0x66, 0x75, 0x74, 0x75, 0x72, 0x65, 0x2c, 0x20, 0x73, 0x75, 0x6e, 0x73,
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0x63, 0x72, 0x65, 0x65, 0x6e, 0x20, 0x77, 0x6f, 0x75, 0x6c, 0x64, 0x20, 0x62, 0x65, 0x20, 0x69,
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0x74, 0x2e,
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};
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var out: [exp_out.len]u8 = undefined;
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try chacha20poly1305Open(out[0..], ciphertext[0..], data[0..], key, nonce);
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testing.expectEqualSlices(u8, exp_out[0..], out[0..]);
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// corrupting the ciphertext, data, key, or nonce should cause a failure
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var bad_ciphertext = ciphertext;
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bad_ciphertext[0] ^= 1;
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testing.expectError(error.AuthenticationFailed, chacha20poly1305Open(out[0..], bad_ciphertext[0..], data[0..], key, nonce));
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var bad_data = data;
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bad_data[0] ^= 1;
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testing.expectError(error.AuthenticationFailed, chacha20poly1305Open(out[0..], ciphertext[0..], bad_data[0..], key, nonce));
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var bad_key = key;
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bad_key[0] ^= 1;
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testing.expectError(error.AuthenticationFailed, chacha20poly1305Open(out[0..], ciphertext[0..], data[0..], bad_key, nonce));
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var bad_nonce = nonce;
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bad_nonce[0] ^= 1;
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testing.expectError(error.AuthenticationFailed, chacha20poly1305Open(out[0..], ciphertext[0..], data[0..], key, bad_nonce));
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// a short ciphertext should result in a different error
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testing.expectError(error.InvalidMessage, chacha20poly1305Open(out[0..], "", data[0..], key, bad_nonce));
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}
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}
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