From 0040881b84263f583112282e3e58ace207a5c22c Mon Sep 17 00:00:00 2001
From: v2ray <admin@v2ray.com>
Date: Tue, 26 Jul 2016 21:21:22 +0200
Subject: [PATCH] comments

---
 common/crypto/aes.go      | 4 ++++
 common/crypto/chacha20.go | 2 ++
 2 files changed, 6 insertions(+)

diff --git a/common/crypto/aes.go b/common/crypto/aes.go
index cae00cb0..64967a33 100644
--- a/common/crypto/aes.go
+++ b/common/crypto/aes.go
@@ -5,11 +5,15 @@ import (
 	"crypto/cipher"
 )
 
+// NewAesDecryptionStream creates a new AES encryption stream based on given key and IV.
+// Caller must ensure the length of key and IV is either 16, 24 or 32 bytes.
 func NewAesDecryptionStream(key []byte, iv []byte) cipher.Stream {
 	aesBlock, _ := aes.NewCipher(key)
 	return cipher.NewCFBDecrypter(aesBlock, iv)
 }
 
+// NewAesEncryptionStream creates a new AES description stream based on given key and IV.
+// Caller must ensure the length of key and IV is either 16, 24 or 32 bytes.
 func NewAesEncryptionStream(key []byte, iv []byte) cipher.Stream {
 	aesBlock, _ := aes.NewCipher(key)
 	return cipher.NewCFBEncrypter(aesBlock, iv)
diff --git a/common/crypto/chacha20.go b/common/crypto/chacha20.go
index 699a00fa..e9b4b0a6 100644
--- a/common/crypto/chacha20.go
+++ b/common/crypto/chacha20.go
@@ -6,6 +6,8 @@ import (
 	"github.com/v2ray/v2ray-core/common/crypto/internal"
 )
 
+// NewChaCha20Stream creates a new Chacha20 encryption/descryption stream based on give key and IV.
+// Caller must ensure the length of key is 32 bytes, and length of IV is either 8 or 12 bytes.
 func NewChaCha20Stream(key []byte, iv []byte) cipher.Stream {
 	return internal.NewChaCha20Stream(key, iv, 20)
 }