Merge pull request #98 from zmanian/xChaChaPoly1035

Implementation of xchacha20poly1035 aead

xchacha20poly1305/xchachapoly.go

@@ -0,0 +1,238 @@
+package xchacha20poly1305
+
+import (
+	"crypto/cipher"
+	"encoding/binary"
+	"errors"
+	"fmt"
+
+	"golang.org/x/crypto/chacha20poly1305"
+)
+
+var sigma = [4]uint32{0x61707865, 0x3320646e, 0x79622d32, 0x6b206574}
+
+type xchacha20poly1305 struct {
+	key [KeySize]byte
+}
+
+const (
+	// KeySize is the size of the key used by this AEAD, in bytes.
+	KeySize = 32
+	// NonceSize is the size of the nonce used with this AEAD, in bytes.
+	NonceSize = 24
+)
+
+//New xChaChapoly1305 AEAD with 24 byte nonces
+func New(key []byte) (cipher.AEAD, error) {
+	if len(key) != KeySize {
+		return nil, errors.New("chacha20poly1305: bad key length")
+	}
+	ret := new(xchacha20poly1305)
+	copy(ret.key[:], key)
+	return ret, nil
+
+}
+func (c *xchacha20poly1305) NonceSize() int {
+	return NonceSize
+}
+
+func (c *xchacha20poly1305) Overhead() int {
+	return 16
+}
+
+func (c *xchacha20poly1305) Seal(dst, nonce, plaintext, additionalData []byte) []byte {
+	if len(nonce) != NonceSize {
+		panic("xchacha20poly1305: bad nonce length passed to Seal")
+	}
+
+	if uint64(len(plaintext)) > (1<<38)-64 {
+		panic("xchacha20poly1305: plaintext too large")
+	}
+
+	var subKey [KeySize]byte
+	var hNonce [16]byte
+	var subNonce [chacha20poly1305.NonceSize]byte
+	copy(hNonce[:], nonce[:16])
+
+	HChaCha20(&subKey, &hNonce, &c.key)
+
+	chacha20poly1305, _ := chacha20poly1305.New(subKey[:])
+
+	copy(subNonce[4:], nonce[16:])
+
+	return chacha20poly1305.Seal(dst, subNonce[:], plaintext, additionalData)
+}
+
+func (c *xchacha20poly1305) Open(dst, nonce, ciphertext, additionalData []byte) ([]byte, error) {
+	if len(nonce) != NonceSize {
+		return nil, fmt.Errorf("xchacha20poly1305: bad nonce length passed to Open")
+	}
+	if uint64(len(ciphertext)) > (1<<38)-48 {
+		return nil, fmt.Errorf("xchacha20poly1305: ciphertext too large")
+	}
+	var subKey [KeySize]byte
+	var hNonce [16]byte
+	var subNonce [chacha20poly1305.NonceSize]byte
+	copy(hNonce[:], nonce[:16])
+
+	HChaCha20(&subKey, &hNonce, &c.key)
+
+	chacha20poly1305, _ := chacha20poly1305.New(subKey[:])
+
+	copy(subNonce[4:], nonce[16:])
+
+	return chacha20poly1305.Open(dst, subNonce[:], ciphertext, additionalData)
+}
+
+// The MIT License (MIT)
+
+// Copyright (c) 2016 Andreas Auernhammer
+
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+// HChaCha20 generates 32 pseudo-random bytes from a 128 bit nonce and a 256 bit secret key.
+// It can be used as a key-derivation-function (KDF).
+func HChaCha20(out *[32]byte, nonce *[16]byte, key *[32]byte) { hChaCha20Generic(out, nonce, key) }
+
+func hChaCha20Generic(out *[32]byte, nonce *[16]byte, key *[32]byte) {
+	v00 := sigma[0]
+	v01 := sigma[1]
+	v02 := sigma[2]
+	v03 := sigma[3]
+	v04 := binary.LittleEndian.Uint32(key[0:])
+	v05 := binary.LittleEndian.Uint32(key[4:])
+	v06 := binary.LittleEndian.Uint32(key[8:])
+	v07 := binary.LittleEndian.Uint32(key[12:])
+	v08 := binary.LittleEndian.Uint32(key[16:])
+	v09 := binary.LittleEndian.Uint32(key[20:])
+	v10 := binary.LittleEndian.Uint32(key[24:])
+	v11 := binary.LittleEndian.Uint32(key[28:])
+	v12 := binary.LittleEndian.Uint32(nonce[0:])
+	v13 := binary.LittleEndian.Uint32(nonce[4:])
+	v14 := binary.LittleEndian.Uint32(nonce[8:])
+	v15 := binary.LittleEndian.Uint32(nonce[12:])
+
+	for i := 0; i < 20; i += 2 {
+		v00 += v04
+		v12 ^= v00
+		v12 = (v12 << 16) | (v12 >> 16)
+		v08 += v12
+		v04 ^= v08
+		v04 = (v04 << 12) | (v04 >> 20)
+		v00 += v04
+		v12 ^= v00
+		v12 = (v12 << 8) | (v12 >> 24)
+		v08 += v12
+		v04 ^= v08
+		v04 = (v04 << 7) | (v04 >> 25)
+		v01 += v05
+		v13 ^= v01
+		v13 = (v13 << 16) | (v13 >> 16)
+		v09 += v13
+		v05 ^= v09
+		v05 = (v05 << 12) | (v05 >> 20)
+		v01 += v05
+		v13 ^= v01
+		v13 = (v13 << 8) | (v13 >> 24)
+		v09 += v13
+		v05 ^= v09
+		v05 = (v05 << 7) | (v05 >> 25)
+		v02 += v06
+		v14 ^= v02
+		v14 = (v14 << 16) | (v14 >> 16)
+		v10 += v14
+		v06 ^= v10
+		v06 = (v06 << 12) | (v06 >> 20)
+		v02 += v06
+		v14 ^= v02
+		v14 = (v14 << 8) | (v14 >> 24)
+		v10 += v14
+		v06 ^= v10
+		v06 = (v06 << 7) | (v06 >> 25)
+		v03 += v07
+		v15 ^= v03
+		v15 = (v15 << 16) | (v15 >> 16)
+		v11 += v15
+		v07 ^= v11
+		v07 = (v07 << 12) | (v07 >> 20)
+		v03 += v07
+		v15 ^= v03
+		v15 = (v15 << 8) | (v15 >> 24)
+		v11 += v15
+		v07 ^= v11
+		v07 = (v07 << 7) | (v07 >> 25)
+		v00 += v05
+		v15 ^= v00
+		v15 = (v15 << 16) | (v15 >> 16)
+		v10 += v15
+		v05 ^= v10
+		v05 = (v05 << 12) | (v05 >> 20)
+		v00 += v05
+		v15 ^= v00
+		v15 = (v15 << 8) | (v15 >> 24)
+		v10 += v15
+		v05 ^= v10
+		v05 = (v05 << 7) | (v05 >> 25)
+		v01 += v06
+		v12 ^= v01
+		v12 = (v12 << 16) | (v12 >> 16)
+		v11 += v12
+		v06 ^= v11
+		v06 = (v06 << 12) | (v06 >> 20)
+		v01 += v06
+		v12 ^= v01
+		v12 = (v12 << 8) | (v12 >> 24)
+		v11 += v12
+		v06 ^= v11
+		v06 = (v06 << 7) | (v06 >> 25)
+		v02 += v07
+		v13 ^= v02
+		v13 = (v13 << 16) | (v13 >> 16)
+		v08 += v13
+		v07 ^= v08
+		v07 = (v07 << 12) | (v07 >> 20)
+		v02 += v07
+		v13 ^= v02
+		v13 = (v13 << 8) | (v13 >> 24)
+		v08 += v13
+		v07 ^= v08
+		v07 = (v07 << 7) | (v07 >> 25)
+		v03 += v04
+		v14 ^= v03
+		v14 = (v14 << 16) | (v14 >> 16)
+		v09 += v14
+		v04 ^= v09
+		v04 = (v04 << 12) | (v04 >> 20)
+		v03 += v04
+		v14 ^= v03
+		v14 = (v14 << 8) | (v14 >> 24)
+		v09 += v14
+		v04 ^= v09
+		v04 = (v04 << 7) | (v04 >> 25)
+	}
+
+	binary.LittleEndian.PutUint32(out[0:], v00)
+	binary.LittleEndian.PutUint32(out[4:], v01)
+	binary.LittleEndian.PutUint32(out[8:], v02)
+	binary.LittleEndian.PutUint32(out[12:], v03)
+	binary.LittleEndian.PutUint32(out[16:], v12)
+	binary.LittleEndian.PutUint32(out[20:], v13)
+	binary.LittleEndian.PutUint32(out[24:], v14)
+	binary.LittleEndian.PutUint32(out[28:], v15)
+}

xchacha20poly1305/xchachapoly_test.go

@@ -0,0 +1,103 @@
+package xchacha20poly1305
+
+import (
+	"bytes"
+	"encoding/hex"
+	"testing"
+)
+
+func toHex(bits []byte) string {
+	return hex.EncodeToString(bits)
+}
+
+func fromHex(bits string) []byte {
+	b, err := hex.DecodeString(bits)
+	if err != nil {
+		panic(err)
+	}
+	return b
+}
+
+func TestHChaCha20(t *testing.T) {
+	for i, v := range hChaCha20Vectors {
+		var key [32]byte
+		var nonce [16]byte
+		copy(key[:], v.key)
+		copy(nonce[:], v.nonce)
+
+		HChaCha20(&key, &nonce, &key)
+		if !bytes.Equal(key[:], v.keystream) {
+			t.Errorf("Test %d: keystream mismatch:\n \t got:  %s\n \t want: %s", i, toHex(key[:]), toHex(v.keystream))
+		}
+	}
+}
+
+var hChaCha20Vectors = []struct {
+	key, nonce, keystream []byte
+}{
+	{
+		fromHex("0000000000000000000000000000000000000000000000000000000000000000"),
+		fromHex("000000000000000000000000000000000000000000000000"),
+		fromHex("1140704c328d1d5d0e30086cdf209dbd6a43b8f41518a11cc387b669b2ee6586"),
+	},
+	{
+		fromHex("8000000000000000000000000000000000000000000000000000000000000000"),
+		fromHex("000000000000000000000000000000000000000000000000"),
+		fromHex("7d266a7fd808cae4c02a0a70dcbfbcc250dae65ce3eae7fc210f54cc8f77df86"),
+	},
+	{
+		fromHex("0000000000000000000000000000000000000000000000000000000000000001"),
+		fromHex("000000000000000000000000000000000000000000000002"),
+		fromHex("e0c77ff931bb9163a5460c02ac281c2b53d792b1c43fea817e9ad275ae546963"),
+	},
+	{
+		fromHex("000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f"),
+		fromHex("000102030405060708090a0b0c0d0e0f1011121314151617"),
+		fromHex("51e3ff45a895675c4b33b46c64f4a9ace110d34df6a2ceab486372bacbd3eff6"),
+	},
+	{
+		fromHex("24f11cce8a1b3d61e441561a696c1c1b7e173d084fd4812425435a8896a013dc"),
+		fromHex("d9660c5900ae19ddad28d6e06e45fe5e"),
+		fromHex("5966b3eec3bff1189f831f06afe4d4e3be97fa9235ec8c20d08acfbbb4e851e3"),
+	},
+}
+
+func TestVectors(t *testing.T) {
+	for i, v := range vectors {
+		if len(v.plaintext) == 0 {
+			v.plaintext = make([]byte, len(v.ciphertext))
+		}
+
+		var nonce [24]byte
+		copy(nonce[:], v.nonce)
+
+		aead, err := New(v.key)
+		if err != nil {
+			t.Error(err)
+		}
+
+		dst := aead.Seal(nil, nonce[:], v.plaintext, v.ad)
+		if !bytes.Equal(dst, v.ciphertext) {
+			t.Errorf("Test %d: ciphertext mismatch:\n \t got:  %s\n \t want: %s", i, toHex(dst), toHex(v.ciphertext))
+		}
+		open, err := aead.Open(nil, nonce[:], dst, v.ad)
+		if err != nil {
+			t.Error(err)
+		}
+		if !bytes.Equal(open, v.plaintext) {
+			t.Errorf("Test %d: plaintext mismatch:\n \t got:  %s\n \t want: %s", i, string(open), string(v.plaintext))
+		}
+	}
+}
+
+var vectors = []struct {
+	key, nonce, ad, plaintext, ciphertext []byte
+}{
+	{
+		[]byte{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},
+		[]byte{0x07, 0x00, 0x00, 0x00, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a, 0x4b},
+		[]byte{0x50, 0x51, 0x52, 0x53, 0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7},
+		[]byte("Ladies and Gentlemen of the class of '99: If I could offer you only one tip for the future, sunscreen would be it."),
+		[]byte{0x45, 0x3c, 0x06, 0x93, 0xa7, 0x40, 0x7f, 0x04, 0xff, 0x4c, 0x56, 0xae, 0xdb, 0x17, 0xa3, 0xc0, 0xa1, 0xaf, 0xff, 0x01, 0x17, 0x49, 0x30, 0xfc, 0x22, 0x28, 0x7c, 0x33, 0xdb, 0xcf, 0x0a, 0xc8, 0xb8, 0x9a, 0xd9, 0x29, 0x53, 0x0a, 0x1b, 0xb3, 0xab, 0x5e, 0x69, 0xf2, 0x4c, 0x7f, 0x60, 0x70, 0xc8, 0xf8, 0x40, 0xc9, 0xab, 0xb4, 0xf6, 0x9f, 0xbf, 0xc8, 0xa7, 0xff, 0x51, 0x26, 0xfa, 0xee, 0xbb, 0xb5, 0x58, 0x05, 0xee, 0x9c, 0x1c, 0xf2, 0xce, 0x5a, 0x57, 0x26, 0x32, 0x87, 0xae, 0xc5, 0x78, 0x0f, 0x04, 0xec, 0x32, 0x4c, 0x35, 0x14, 0x12, 0x2c, 0xfc, 0x32, 0x31, 0xfc, 0x1a, 0x8b, 0x71, 0x8a, 0x62, 0x86, 0x37, 0x30, 0xa2, 0x70, 0x2b, 0xb7, 0x63, 0x66, 0x11, 0x6b, 0xed, 0x09, 0xe0, 0xfd, 0x5c, 0x6d, 0x84, 0xb6, 0xb0, 0xc1, 0xab, 0xaf, 0x24, 0x9d, 0x5d, 0xd0, 0xf7, 0xf5, 0xa7, 0xea},
+	},
+}