From 72ea01d56600051378f5b6dc6736481b77091aae Mon Sep 17 00:00:00 2001
From: Gang Zhuo <gang.zhuo@gmail.com>
Date: Tue, 15 Sep 2015 06:48:23 -0400
Subject: [PATCH] no repeat random number generator

The stock code use class Random to generate IV, the Random is pseudo random number generator. The IV maybe repeat, this will cause shadowsocks-libev closed the sockets with the error message 'invalid password or cipher'. Reference https://github.com/shadowsocks/shadowsocks-libev/issues/389

Solution is use class RNGCryptoServiceProvider to generate IV, of course it's lower performance, but a little bit.
---
 shadowsocks-csharp/Encryption/IVEncryptor.cs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/shadowsocks-csharp/Encryption/IVEncryptor.cs b/shadowsocks-csharp/Encryption/IVEncryptor.cs
index 32948d6b..b82d3adf 100755
--- a/shadowsocks-csharp/Encryption/IVEncryptor.cs
+++ b/shadowsocks-csharp/Encryption/IVEncryptor.cs
@@ -88,7 +88,8 @@ namespace Shadowsocks.Encryption
         protected static void randBytes(byte[] buf, int length)
         {
             byte[] temp = new byte[length];
-            new Random().NextBytes(temp);
+            RNGCryptoServiceProvider rngServiceProvider = new RNGCryptoServiceProvider();
+            rngServiceProvider.GetBytes(temp);
             temp.CopyTo(buf, 0);
         }