The Anatomy of Forms Authentication

using System;
using System.Collections.Generic;
using System.Text;
using System.Security.Cryptography;

namespace GSS.Web.Security
{
    static class Utils
    {
        /// <summary>
        /// Generates a random bytes using RNGCryptoServiceProvider
        /// </summary>
        /// <param name="count">Number of bytes to return</param>
        /// <returns>A randomly generated bytes array of the specified length</returns>
        public static byte[] GetRandomBytes(int count)
        {
            byte[] randomBytes = new byte[count];
            RNGCryptoServiceProvider gen = new RNGCryptoServiceProvider();
            gen.GetBytes(randomBytes);
            return randomBytes;
        }
        /// <summary>
        /// Converts a byte array to a hex string
        /// </summary>
        /// <param name="bytes">Bytes to convert</param>
        /// <returns>Formatted hex string</returns>
        public static string ByteArrayToHexString(byte[] bytes)
        {
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < bytes.Length; i++)
            {
                sb.Append(bytes[i].ToString("X2"));
            }
            return sb.ToString();
        }
        /// <summary>
        /// Converts a hex string to a byte array
        /// </summary>
        /// <param name="hexString">The hex string to convert</param>
        /// <returns>A byte array representing the hex string</returns>
        public static byte[] HexStringToByteArray(string hexString)
        {
            byte[] returnBytes = new byte[hexString.Length / 2];
            for (int i = 0; i < returnBytes.Length; i++)
                returnBytes[i] = Convert.ToByte(hexString.Substring(i * 2, 2), 16);
            return returnBytes;
        }
        /// <summary>
        /// Convert a DateTime to the equivalent long (Win32 FileTime) byte array
        /// </summary>
        /// <param name="date">DateTime to convert</param>
        /// <returns>"long" byte array representing the DateTime</returns>
        public static byte[] DateToByteArray(DateTime date)
        {
            long longDate = date.ToFileTime();
            return BitConverter.GetBytes(longDate);
        }
        /// <summary>
        /// Coverts a long (aka Win32 FileTime) byte array to a DateTime
        /// </summary>
        /// <param name="bytes">Bytes to convert</param>
        /// <returns>DateTime representation of the "long" bytes</returns>
        public static DateTime ByteArrayToDate(byte[] bytes)
        {
            if (bytes.Length != 8)
                throw new ArgumentException("bytes");
            long longDate = BitConverter.ToInt64(bytes, 0);
            return DateTime.FromFileTime(longDate);
        }

    }
}