using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine(ToGuidFromOracleString("587117680158F04AA97B727A5AC94CEA"));

    }       

​

public static string ToOracleString(Guid guid)

        {

            var buffer = guid.ToByteArray();

            var newBuffer = new byte[]{

                (byte)buffer.GetValue(3),

                (byte)buffer.GetValue(2),

                (byte)buffer.GetValue(1),

                (byte)buffer.GetValue(0),

                (byte)buffer.GetValue(5),

                (byte)buffer.GetValue(4),

                (byte)buffer.GetValue(7),

                (byte)buffer.GetValue(6),

                (byte)buffer.GetValue(8),

                (byte)buffer.GetValue(9),

                (byte)buffer.GetValue(10),

                (byte)buffer.GetValue(11),

                (byte)buffer.GetValue(12),

                (byte)buffer.GetValue(13),

                (byte)buffer.GetValue(14),

                (byte)buffer.GetValue(15)};

            return (new Guid(newBuffer)).ToString("N").ToUpper();

        }

​

        public static Guid ToGuidFromOracleString(string oracleStr)

        {

            var guid = new Guid(oracleStr);

            var buffer = guid.ToByteArray();

            var newBuffer = new byte[]{

                (byte)buffer.GetValue(3),

                (byte)buffer.GetValue(2),

                (byte)buffer.GetValue(1),

                (byte)buffer.GetValue(0),

                (byte)buffer.GetValue(5),

                (byte)buffer.GetValue(4),

                (byte)buffer.GetValue(7),

                (byte)buffer.GetValue(6),

                (byte)buffer.GetValue(8),

                (byte)buffer.GetValue(9),

                (byte)buffer.GetValue(10),

                (byte)buffer.GetValue(11),

                (byte)buffer.GetValue(12),

                (byte)buffer.GetValue(13),

                (byte)buffer.GetValue(14),

                (byte)buffer.GetValue(15)};

            return new Guid(newBuffer);

        }

}