From b5a27d3aa20cc6a52c395c6c88a9fbf828781bc7 Mon Sep 17 00:00:00 2001
From: Lucas Clemente <lucas@clemente.io>
Date: Thu, 5 May 2016 15:19:54 +0200
Subject: [PATCH] move to chacha20poly1305 fork

---
 crypto/chacha20poly1305_aead.go               |   7 +-
 .../chacha20poly1305.go                       | 133 ------------------
 2 files changed, 4 insertions(+), 136 deletions(-)
 delete mode 100644 crypto/chacha20poly1305trunc12/chacha20poly1305.go

diff --git a/crypto/chacha20poly1305_aead.go b/crypto/chacha20poly1305_aead.go
index 4098b5f5..da5b4fe9 100644
--- a/crypto/chacha20poly1305_aead.go
+++ b/crypto/chacha20poly1305_aead.go
@@ -5,7 +5,8 @@ import (
 	"encoding/binary"
 	"errors"
 
-	"github.com/lucas-clemente/quic-go/crypto/chacha20poly1305trunc12"
+	"github.com/lucas-clemente/crypto/chacha"
+
 	"github.com/lucas-clemente/quic-go/protocol"
 )
 
@@ -21,11 +22,11 @@ func NewAEADChacha20Poly1305(otherKey []byte, myKey []byte, otherIV []byte, myIV
 	if len(myKey) != 32 || len(otherKey) != 32 || len(myIV) != 4 || len(otherIV) != 4 {
 		return nil, errors.New("chacha20poly1305: expected 32-byte keys and 4-byte IVs")
 	}
-	encrypter, err := chacha20poly1305trunc12.NewAEAD(myKey)
+	encrypter, err := chacha.NewAEADTagSize(myKey, 12)
 	if err != nil {
 		return nil, err
 	}
-	decrypter, err := chacha20poly1305trunc12.NewAEAD(otherKey)
+	decrypter, err := chacha.NewAEADTagSize(otherKey, 12)
 	if err != nil {
 		return nil, err
 	}
diff --git a/crypto/chacha20poly1305trunc12/chacha20poly1305.go b/crypto/chacha20poly1305trunc12/chacha20poly1305.go
deleted file mode 100644
index 25c95129..00000000
--- a/crypto/chacha20poly1305trunc12/chacha20poly1305.go
+++ /dev/null
@@ -1,133 +0,0 @@
-// Taken and modified to have tag size = 12
-// from https://github.com/EncEve/crypto/blob/master/chacha/chachaPoly1305.go
-// TODO: Check, make independent
-
-package chacha20poly1305trunc12
-
-// Use of this source code is governed by a license
-// that can be found in the LICENSE file.
-
-import (
-	"crypto/cipher"
-	"crypto/subtle"
-
-	"github.com/EncEve/crypto"
-	"github.com/EncEve/crypto/chacha"
-	"github.com/EncEve/crypto/poly1305"
-)
-
-// The AEAD cipher ChaCha20-Poly1305
-type aeadCipher struct {
-	key [32]byte
-}
-
-// NewAEAD returns a cipher.AEAD implementing the
-// ChaCha20-Poly1305 construction specified in
-// RFC 7539. The key argument must be 256 bit
-// (32 byte).
-func NewAEAD(key []byte) (cipher.AEAD, error) {
-	if k := len(key); k != 32 {
-		return nil, crypto.KeySizeError(k)
-	}
-	c := new(aeadCipher)
-	for i, v := range key {
-		c.key[i] = v
-	}
-	return c, nil
-}
-
-func (c *aeadCipher) Overhead() int { return 12 }
-
-func (c *aeadCipher) NonceSize() int { return chacha.NonceSize }
-
-func (c *aeadCipher) Seal(dst, nonce, plaintext, additionalData []byte) []byte {
-	if n := len(nonce); n != chacha.NonceSize {
-		panic(crypto.NonceSizeError(n))
-	}
-	if len(dst) < len(plaintext) {
-		panic("dst buffer to small")
-	}
-	var Nonce [12]byte
-	copy(Nonce[:], nonce)
-
-	// create the ploy1305 key
-	var polyKey [32]byte
-	chacha.XORKeyStream(polyKey[:], polyKey[:], &(c.key), &Nonce, 0)
-
-	// encrypt the plaintext
-	n := len(plaintext)
-	chacha.XORKeyStream(dst, plaintext, &(c.key), &Nonce, 1)
-
-	// authenticate the ciphertext
-	tag := authenticate(&polyKey, dst[:n], additionalData)
-	return append(dst[:n], tag[0:12]...)
-}
-
-func (c *aeadCipher) Open(dst, nonce, ciphertext, additionalData []byte) ([]byte, error) {
-	if n := len(nonce); n != chacha.NonceSize {
-		return nil, crypto.NonceSizeError(n)
-	}
-	if len(ciphertext) < 12 {
-		return nil, crypto.AuthenticationError{}
-	}
-	if len(dst) < len(ciphertext)-12 {
-		panic("dst buffer to small")
-	}
-	var Nonce [12]byte
-	copy(Nonce[:], nonce)
-
-	hash := ciphertext[len(ciphertext)-12:]
-	ciphertext = ciphertext[:len(ciphertext)-12]
-
-	// create the ploy1305 key
-	var polyKey [32]byte
-	chacha.XORKeyStream(polyKey[:], polyKey[:], &(c.key), &Nonce, 0)
-
-	// authenticate the ciphertext
-	tag := authenticate(&polyKey, ciphertext, additionalData)
-	if subtle.ConstantTimeCompare(tag[0:12], hash[0:12]) != 1 {
-		return nil, crypto.AuthenticationError{}
-	}
-
-	// decrypt ciphertext
-	chacha.XORKeyStream(dst, ciphertext, &(c.key), &Nonce, 1)
-	return dst[:len(ciphertext)], nil
-}
-
-// authenticate calculates the poly1305 tag from
-// the given ciphertext and additional data.
-func authenticate(key *[32]byte, ciphertext, additionalData []byte) []byte {
-	ctLen := uint64(len(ciphertext))
-	adLen := uint64(len(additionalData))
-	padAD, padCT := adLen%16, ctLen%16
-
-	var buf [16]byte
-	buf[0] = byte(adLen)
-	buf[1] = byte(adLen >> 8)
-	buf[2] = byte(adLen >> 16)
-	buf[3] = byte(adLen >> 24)
-	buf[4] = byte(adLen >> 32)
-	buf[5] = byte(adLen >> 40)
-	buf[6] = byte(adLen >> 48)
-	buf[7] = byte(adLen >> 56)
-	buf[8] = byte(ctLen)
-	buf[9] = byte(ctLen >> 8)
-	buf[10] = byte(ctLen >> 16)
-	buf[11] = byte(ctLen >> 24)
-	buf[12] = byte(ctLen >> 32)
-	buf[13] = byte(ctLen >> 40)
-	buf[14] = byte(ctLen >> 48)
-	buf[15] = byte(ctLen >> 56)
-
-	poly, _ := poly1305.New(key[:])
-	poly.Write(additionalData)
-	if padAD > 0 {
-		poly.Write(make([]byte, 16-padAD))
-	}
-	poly.Write(ciphertext)
-	if padCT > 0 {
-		poly.Write(make([]byte, 16-padCT))
-	}
-	poly.Write(buf[:])
-	return poly.Sum(nil)
-}