RandomExtensions is a container of extensions to System.Random class.

RandomExtensions.cs

using System;

namespace Konard.Helpers
{
    public static class RandomExtensions
    {
        public static string NextString(this Random rnd, int length)
        {
            if (length <= 0)
                return String.Empty;

            return rnd.NextBytes(length).ConvertToString();
        }

        public static byte[] NextBytes(this Random rnd, int length)
        {
            if (length <= 0)
                return new byte[0];

            byte[] randomBytes = new byte[length];
            rnd.NextBytes(randomBytes);
            return randomBytes;
        }
        
        public static ulong NextUInt64(this Random rnd)
        {
            return rnd.NextUInt64(UInt64.MaxValue);
        }

        public static ulong NextUInt64(this Random rnd, ulong maxValue)
        {
            return rnd.NextUInt64(UInt64.MinValue, maxValue);
        }

        public static ulong NextUInt64(this Random rnd, ulong minValue, ulong maxValue)
        {
            if (minValue >= maxValue)
                return minValue;
            return (ulong)(rnd.NextDouble() * (maxValue - minValue)) + minValue;
        }
    }
}