MD5加密

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 sSql = "select userid from users where halt = 0 and userid=" +
                            _oCommon.procStr(UserID) + " and password="
                            + _oCommon.procStr(_oCommon.MD5(PW));

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   /// <summary>
        /// MD5加密
        /// </summary>
        /// <param name="s"></param>
        /// <returns></returns>
        public string MD5(string s)
        {
            byte[] HashData;
            if (String.IsNullOrEmpty(s))
                s = "";
            System.Security.Cryptography.MD5CryptoServiceProvider MD5 = new System.Security.Cryptography.MD5CryptoServiceProvider();
            HashData = MD5.ComputeHash(System.Text.Encoding.GetEncoding("GB2312").GetBytes(s));
            return Convert.ToBase64String(HashData);
        }