[winphone][C#] RSA加密与解密

public static byte[] RSAEncypt(byte[] contentBytes, string key)
{
RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
rsa.FromXmlString(key);
byte[] oText = contentBytes;
List<byte[]> pieceList = new List<byte[]>();
List<byte> oTextList = new List<byte>();
oTextList.AddRange(oText);
int pieces = oText.Length / RSA_PIECE_LENGTH + 1;
//分片
for (int i = 0; i < pieces; i++)
{
int index = i * RSA_PIECE_LENGTH;
byte[] bytes = oTextList.GetRange(index, index + RSA_PIECE_LENGTH > oTextList.Count ? oTextList.Count - index : RSA_PIECE_LENGTH).ToArray();
pieceList.Add(bytes);
}
List<byte> cipherList = new List<byte>();
for (int i = 0; i < pieceList.Count; i++)
{
byte[] cbs = rsa.Encrypt(pieceList[i], false);
cipherList.AddRange(cbs);
}
rsa.Dispose();
return cipherList.ToArray();
}