加密（获得唯一哈希值）

public static string jiami(string password)
    {
        byte[] buffer = System.Text.Encoding.UTF8.GetBytes(password);
        SHA1CryptoServiceProvider sha = new SHA1CryptoServiceProvider();
        byte[] hash = sha.ComputeHash(buffer);
        StringBuilder passwordbullder = new StringBuilder(32);
        foreach (byte hashByte in hash)
        {
            passwordbullder.Append(hashByte.ToString("x2"));

        }
        return passwordbullder.ToString();
    }

            FileStream fs = new FileStream(this.fileFullName, FileMode.Open, FileAccess.Read);
            SHA1CryptoServiceProvider sha1 = new SHA1CryptoServiceProvider();
            Byte[] fileHashes_SHA1 = sha1.ComputeHash(fs);
            MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();
            Byte[] fileHashes_MD5 = md5.ComputeHash(fs);
            //this.fileSize = fs.Length;
            //this.sendSize = 0;
            fs.Close();
            fs.Dispose();