internal string GenerateSalt()
        {
            byte[] buf = new byte[16];
            (new RNGCryptoServiceProvider()).GetBytes(buf);
            return Convert.ToBase64String(buf);
        }
        internal string EncodePassword(string pass, int passwordFormat, string salt)
        {
            if (passwordFormat == 0) // MembershipPasswordFormat.Clear
                return pass;

            byte[] bIn = Encoding.Unicode.GetBytes(pass);
            byte[] bSalt = Convert.FromBase64String(salt);
            byte[] bAll = new byte[bSalt.Length + bIn.Length];
            byte[] bRet = null;

            Buffer.BlockCopy(bSalt, 0, bAll, 0, bSalt.Length);
            Buffer.BlockCopy(bIn, 0, bAll, bSalt.Length, bIn.Length);
            if (passwordFormat == 1)
            { // MembershipPasswordFormat.Hashed
                HashAlgorithm s = HashAlgorithm.Create( Membership.HashAlgorithmType );
                bRet = s.ComputeHash(bAll);
            } else
            {
                bRet = EncryptPassword( bAll );
            }

            return Convert.ToBase64String(bRet);
        }

        internal string UnEncodePassword(string pass, int passwordFormat)
        {
            switch (passwordFormat)
            {
                case 0: // MembershipPasswordFormat.Clear:
                    return pass;
                case 1: // MembershipPasswordFormat.Hashed:
                    throw new ProviderException(SR.GetString(SR.Provider_can_not_decode_hashed_password));
                default:
                    byte[] bIn = Convert.FromBase64String(pass);
                    byte[] bRet = DecryptPassword( bIn );
                    if (bRet == null)
                        return null;
                    return Encoding.Unicode.GetString(bRet, 16, bRet.Length - 16);
            }
        }
    }