BinaryReader binr = new BinaryReader(mem);    //wrap Memory Stream with BinaryReader for easy reading

            byte bt = 0;

            ushort twobytes = 0;

            int elems = 0;

            try

            {

                twobytes = binr.ReadUInt16();

                if (twobytes == 0x8130)    //data read as little endian order (actual data order for Sequence is 30 81)

                    binr.ReadByte();    //advance 1 byte

                else if (twobytes == 0x8230)

                    binr.ReadInt16();    //advance 2 bytes

                else

                    return null;

                twobytes = binr.ReadUInt16();

                if (twobytes != 0x0102)    //version number

                    return null;

                bt = binr.ReadByte();

                if (bt != 0x00)

                    return null;

                //------  all private key components are Integer sequences ----

                elems = GetIntegerSize(binr);

                MODULUS = binr.ReadBytes(elems);

                elems = GetIntegerSize(binr);

                E = binr.ReadBytes(elems);

                elems = GetIntegerSize(binr);

                D = binr.ReadBytes(elems);

                elems = GetIntegerSize(binr);

                P = binr.ReadBytes(elems);

                elems = GetIntegerSize(binr);

                Q = binr.ReadBytes(elems);

                elems = GetIntegerSize(binr);

                DP = binr.ReadBytes(elems);

                elems = GetIntegerSize(binr);

                DQ = binr.ReadBytes(elems);

                elems = GetIntegerSize(binr);

                IQ = binr.ReadBytes(elems);