Replace ChaCha20 implementation with an optimized version

.travis.yml

@@ -7,6 +7,7 @@ before_install:
  - go get golang.org/x/tools/cmd/cover
  - go get github.com/onsi/gomega
  - go get github.com/onsi/ginkgo
+ - go get github.com/aead/chacha20
 
 script:
  - go test -tags json github.com/v2ray/v2ray-core/...

common/crypto/chacha20.go

@@ -3,9 +3,27 @@ package crypto
 import (
  "crypto/cipher"
 
- "github.com/v2ray/v2ray-core/common/crypto/internal"
+ "github.com/aead/chacha20"
 )
 
+func makeNonce(nonce *[chacha20.NonceSize]byte, iv []byte) {
+ switch len(iv) {
+ case 8:
+ copy(nonce[4:], iv)
+ case 12:
+ copy(nonce[:], iv)
+ default:
+ panic("bad nonce length")
+ }
+}
+
 func NewChaCha20Stream(key []byte, iv []byte) cipher.Stream {
- return internal.NewChaCha20Stream(key, iv, 20)
+ var Key [32]byte
+ var Nonce [12]byte
+ if len(key) != 32 {
+ panic("bad key length")
+ }
+ copy(Key[:], key)
+ makeNonce(&Nonce, iv)
+ return chacha20.NewCipher(&Nonce, &Key)
 }