Implement RFC 7539 in Go.
In preparation for a Go implementation of the new TLS ciphers to test
against, implement the AEAD primitive.
Change-Id: I69b5b51257c3de16bdd36912ed2bc9d91ac853c8
Reviewed-on: https://boringssl-review.googlesource.com/6684
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/ssl/test/runner/chacha20_poly1305.go b/ssl/test/runner/chacha20_poly1305.go
index 4b49ff4..59c4dda 100644
--- a/ssl/test/runner/chacha20_poly1305.go
+++ b/ssl/test/runner/chacha20_poly1305.go
@@ -7,9 +7,7 @@
"errors"
)
-// See draft-agl-tls-chacha20poly1305-04 and
-// draft-irtf-cfrg-chacha20-poly1305-10. Where the two differ, the
-// draft-agl-tls-chacha20poly1305-04 variant is implemented.
+// See RFC 7539.
func leftRotate(a uint32, n uint) uint32 {
return (a << n) | (a >> (32 - n))
@@ -62,37 +60,30 @@
return
}
-type chaCha20Poly1305Old struct {
- key [32]byte
-}
-
-func newChaCha20Poly1305Old(key []byte) (cipher.AEAD, error) {
- if len(key) != 32 {
- return nil, errors.New("bad key length")
- }
- aead := new(chaCha20Poly1305Old)
- copy(aead.key[:], key)
- return aead, nil
-}
-
-func (c *chaCha20Poly1305Old) NonceSize() int { return 8 }
-func (c *chaCha20Poly1305Old) Overhead() int { return 16 }
-
-func (c *chaCha20Poly1305Old) chaCha20(out, in, nonce []byte, counter uint64) {
+func chaCha20(out, in, key, nonce []byte, counter uint64) {
var state [16]uint32
state[0] = 0x61707865
state[1] = 0x3320646e
state[2] = 0x79622d32
state[3] = 0x6b206574
for i := 0; i < 8; i++ {
- state[4+i] = binary.LittleEndian.Uint32(c.key[i*4 : i*4+4])
+ state[4+i] = binary.LittleEndian.Uint32(key[i*4 : i*4+4])
}
- state[14] = binary.LittleEndian.Uint32(nonce[0:4])
- state[15] = binary.LittleEndian.Uint32(nonce[4:8])
+
+ switch len(nonce) {
+ case 8:
+ state[14] = binary.LittleEndian.Uint32(nonce[0:4])
+ state[15] = binary.LittleEndian.Uint32(nonce[4:8])
+ case 12:
+ state[13] = binary.LittleEndian.Uint32(nonce[0:4])
+ state[14] = binary.LittleEndian.Uint32(nonce[4:8])
+ state[15] = binary.LittleEndian.Uint32(nonce[8:12])
+ default:
+ panic("bad nonce length")
+ }
for i := 0; i < len(in); i += 64 {
- state[12] = uint32(counter & 0xffffffff)
- state[13] = uint32(counter >> 32)
+ state[12] = uint32(counter)
var tmp [64]byte
chaCha20Block(&state, tmp[:])
@@ -108,7 +99,68 @@
}
}
-func (c *chaCha20Poly1305Old) poly1305(tag *[16]byte, nonce, ciphertext, additionalData []byte) {
+// chaCha20Poly1305 implements the AEAD from
+// RFC 7539 and draft-agl-tls-chacha20poly1305-04.
+type chaCha20Poly1305 struct {
+ key [32]byte
+ // oldMode, if true, indicates that the draft spec should be
+ // implemented rather than the final, RFC version.
+ oldMode bool
+}
+
+func newChaCha20Poly1305(key []byte) (cipher.AEAD, error) {
+ if len(key) != 32 {
+ return nil, errors.New("bad key length")
+ }
+ aead := new(chaCha20Poly1305)
+ copy(aead.key[:], key)
+ return aead, nil
+}
+
+func newChaCha20Poly1305Old(key []byte) (cipher.AEAD, error) {
+ if len(key) != 32 {
+ return nil, errors.New("bad key length")
+ }
+ aead := &chaCha20Poly1305{
+ oldMode: true,
+ }
+ copy(aead.key[:], key)
+ return aead, nil
+}
+
+func (c *chaCha20Poly1305) NonceSize() int {
+ if c.oldMode {
+ return 8
+ } else {
+ return 12
+ }
+}
+
+func (c *chaCha20Poly1305) Overhead() int { return 16 }
+
+func (c *chaCha20Poly1305) poly1305(tag *[16]byte, nonce, ciphertext, additionalData []byte) {
+ input := make([]byte, 0, len(additionalData)+15+len(ciphertext)+15+8+8)
+ input = append(input, additionalData...)
+ var zeros [15]byte
+ if pad := len(input) % 16; pad != 0 {
+ input = append(input, zeros[:16-pad]...)
+ }
+ input = append(input, ciphertext...)
+ if pad := len(input) % 16; pad != 0 {
+ input = append(input, zeros[:16-pad]...)
+ }
+ input, out := sliceForAppend(input, 8)
+ binary.LittleEndian.PutUint64(out, uint64(len(additionalData)))
+ input, out = sliceForAppend(input, 8)
+ binary.LittleEndian.PutUint64(out, uint64(len(ciphertext)))
+
+ var poly1305Key [32]byte
+ chaCha20(poly1305Key[:], poly1305Key[:], c.key[:], nonce, 0)
+
+ poly1305Sum(tag, input, &poly1305Key)
+}
+
+func (c *chaCha20Poly1305) poly1305Old(tag *[16]byte, nonce, ciphertext, additionalData []byte) {
input := make([]byte, 0, len(additionalData)+8+len(ciphertext)+8)
input = append(input, additionalData...)
input, out := sliceForAppend(input, 8)
@@ -118,28 +170,32 @@
binary.LittleEndian.PutUint64(out, uint64(len(ciphertext)))
var poly1305Key [32]byte
- c.chaCha20(poly1305Key[:], poly1305Key[:], nonce, 0)
+ chaCha20(poly1305Key[:], poly1305Key[:], c.key[:], nonce, 0)
poly1305Sum(tag, input, &poly1305Key)
}
-func (c *chaCha20Poly1305Old) Seal(dst, nonce, plaintext, additionalData []byte) []byte {
- if len(nonce) != 8 {
+func (c *chaCha20Poly1305) Seal(dst, nonce, plaintext, additionalData []byte) []byte {
+ if len(nonce) != c.NonceSize() {
panic("Bad nonce length")
}
ret, out := sliceForAppend(dst, len(plaintext)+16)
- c.chaCha20(out[:len(plaintext)], plaintext, nonce, 1)
+ chaCha20(out[:len(plaintext)], plaintext, c.key[:], nonce, 1)
var tag [16]byte
- c.poly1305(&tag, nonce, out[:len(plaintext)], additionalData)
+ if c.oldMode {
+ c.poly1305Old(&tag, nonce, out[:len(plaintext)], additionalData)
+ } else {
+ c.poly1305(&tag, nonce, out[:len(plaintext)], additionalData)
+ }
copy(out[len(plaintext):], tag[:])
return ret
}
-func (c *chaCha20Poly1305Old) Open(dst, nonce, ciphertext, additionalData []byte) ([]byte, error) {
- if len(nonce) != 8 {
+func (c *chaCha20Poly1305) Open(dst, nonce, ciphertext, additionalData []byte) ([]byte, error) {
+ if len(nonce) != c.NonceSize() {
panic("Bad nonce length")
}
if len(ciphertext) < 16 {
@@ -148,12 +204,16 @@
plaintextLen := len(ciphertext) - 16
var tag [16]byte
- c.poly1305(&tag, nonce, ciphertext[:plaintextLen], additionalData)
+ if c.oldMode {
+ c.poly1305Old(&tag, nonce, ciphertext[:plaintextLen], additionalData)
+ } else {
+ c.poly1305(&tag, nonce, ciphertext[:plaintextLen], additionalData)
+ }
if subtle.ConstantTimeCompare(tag[:], ciphertext[plaintextLen:]) != 1 {
return nil, errors.New("chacha20: message authentication failed")
}
ret, out := sliceForAppend(dst, plaintextLen)
- c.chaCha20(out, ciphertext[:plaintextLen], nonce, 1)
+ chaCha20(out, ciphertext[:plaintextLen], c.key[:], nonce, 1)
return ret, nil
}
diff --git a/ssl/test/runner/chacha20_poly1305_test.go b/ssl/test/runner/chacha20_poly1305_test.go
index 446e7cd..4d19b8c 100644
--- a/ssl/test/runner/chacha20_poly1305_test.go
+++ b/ssl/test/runner/chacha20_poly1305_test.go
@@ -6,7 +6,7 @@
"testing"
)
-// See draft-irtf-cfrg-chacha20-poly1305-10, section 2.1.1.
+// See RFC 7539, section 2.1.1.
func TestChaChaQuarterRound(t *testing.T) {
state := [16]uint32{0x11111111, 0x01020304, 0x9b8d6f43, 0x01234567}
chaChaQuarterRound(&state, 0, 1, 2, 3)
@@ -17,7 +17,7 @@
}
}
-// See draft-irtf-cfrg-chacha20-poly1305-10, section 2.2.1.
+// See RFC 7539, section 2.2.1.
func TestChaChaQuarterRoundState(t *testing.T) {
state := [16]uint32{
0x879531e0, 0xc5ecf37d, 0x516461b1, 0xc9a62f8a,
@@ -40,7 +40,7 @@
}
}
-// See draft-irtf-cfrg-chacha20-poly1305-10, section 2.3.2.
+// See RFC 7539, section 2.3.2.
func TestChaCha20Block(t *testing.T) {
state := [16]uint32{
0x61707865, 0x3320646e, 0x79622d32, 0x6b206574,
@@ -66,13 +66,21 @@
}
}
+func decodeHexOrPanic(in string) []byte {
+ out, err := hex.DecodeString(in)
+ if err != nil {
+ panic(err)
+ }
+ return out
+}
+
// See draft-agl-tls-chacha20poly1305-04, section 7.
func TestChaCha20Poly1305Old(t *testing.T) {
- key, _ := hex.DecodeString("4290bcb154173531f314af57f3be3b5006da371ece272afa1b5dbdd1100a1007")
- input, _ := hex.DecodeString("86d09974840bded2a5ca")
- nonce, _ := hex.DecodeString("cd7cf67be39c794a")
- ad, _ := hex.DecodeString("87e229d4500845a079c0")
- output, _ := hex.DecodeString("e3e446f7ede9a19b62a4677dabf4e3d24b876bb284753896e1d6")
+ key := decodeHexOrPanic("4290bcb154173531f314af57f3be3b5006da371ece272afa1b5dbdd1100a1007")
+ input := decodeHexOrPanic("86d09974840bded2a5ca")
+ nonce := decodeHexOrPanic("cd7cf67be39c794a")
+ ad := decodeHexOrPanic("87e229d4500845a079c0")
+ output := decodeHexOrPanic("e3e446f7ede9a19b62a4677dabf4e3d24b876bb284753896e1d6")
aead, err := newChaCha20Poly1305Old(key)
if err != nil {
@@ -97,3 +105,58 @@
t.Errorf("Open on malformed data unexpectedly succeeded")
}
}
+
+var chaCha20Poly1305TestVectors = []struct {
+ key, input, nonce, ad, output string
+}{
+ {
+ // See RFC 7539, section 2.8.2.
+ key: "808182838485868788898a8b8c8d8e8f909192939495969798999a9b9c9d9e9f",
+ input: "4c616469657320616e642047656e746c656d656e206f662074686520636c617373206f66202739393a204966204920636f756c64206f6666657220796f75206f6e6c79206f6e652074697020666f7220746865206675747572652c2073756e73637265656e20776f756c642062652069742e",
+ nonce: "070000004041424344454647",
+ ad: "50515253c0c1c2c3c4c5c6c7",
+ output: "d31a8d34648e60db7b86afbc53ef7ec2a4aded51296e08fea9e2b5a736ee62d63dbea45e8ca9671282fafb69da92728b1a71de0a9e060b2905d6a5b67ecd3b3692ddbd7f2d778b8c9803aee328091b58fab324e4fad675945585808b4831d7bc3ff4def08e4b7a9de576d26586cec64b61161ae10b594f09e26a7e902ecbd0600691",
+ },
+ {
+ // See RFC 7539, section A.5.
+ key: "1c9240a5eb55d38af333888604f6b5f0473917c1402b80099dca5cbc207075c0",
+ input: "496e7465726e65742d4472616674732061726520647261667420646f63756d656e74732076616c696420666f722061206d6178696d756d206f6620736978206d6f6e74687320616e64206d617920626520757064617465642c207265706c616365642c206f72206f62736f6c65746564206279206f7468657220646f63756d656e747320617420616e792074696d652e20497420697320696e617070726f70726961746520746f2075736520496e7465726e65742d447261667473206173207265666572656e6365206d6174657269616c206f7220746f2063697465207468656d206f74686572207468616e206173202fe2809c776f726b20696e2070726f67726573732e2fe2809d",
+ nonce: "000000000102030405060708",
+ ad: "f33388860000000000004e91",
+ output: "64a0861575861af460f062c79be643bd5e805cfd345cf389f108670ac76c8cb24c6cfc18755d43eea09ee94e382d26b0bdb7b73c321b0100d4f03b7f355894cf332f830e710b97ce98c8a84abd0b948114ad176e008d33bd60f982b1ff37c8559797a06ef4f0ef61c186324e2b3506383606907b6a7c02b0f9f6157b53c867e4b9166c767b804d46a59b5216cde7a4e99040c5a40433225ee282a1b0a06c523eaf4534d7f83fa1155b0047718cbc546a0d072b04b3564eea1b422273f548271a0bb2316053fa76991955ebd63159434ecebb4e466dae5a1073a6727627097a1049e617d91d361094fa68f0ff77987130305beaba2eda04df997b714d6c6f2c29a6ad5cb4022b02709beead9d67890cbb22392336fea1851f38",
+ },
+}
+
+// See draft-agl-tls-chacha20poly1305-04, section 7.
+func TestChaCha20Poly1305(t *testing.T) {
+ for i, tt := range chaCha20Poly1305TestVectors {
+ key := decodeHexOrPanic(tt.key)
+ input := decodeHexOrPanic(tt.input)
+ nonce := decodeHexOrPanic(tt.nonce)
+ ad := decodeHexOrPanic(tt.ad)
+ output := decodeHexOrPanic(tt.output)
+
+ aead, err := newChaCha20Poly1305(key)
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ out, err := aead.Open(nil, nonce, output, ad)
+ if err != nil {
+ t.Errorf("%d. Open failed: %s", i, err)
+ } else if !bytes.Equal(out, input) {
+ t.Errorf("%d. Open gave %x, wanted %x", i, out, input)
+ }
+
+ out = aead.Seal(nil, nonce, input, ad)
+ if !bytes.Equal(out, output) {
+ t.Errorf("%d. Open gave %x, wanted %x", i, out, output)
+ }
+
+ out[0]++
+ _, err = aead.Open(nil, nonce, out, ad)
+ if err == nil {
+ t.Errorf("%d. Open on malformed data unexpectedly succeeded", i)
+ }
+ }
+}
