using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Security.Cryptography;

namespace Classes
{
    public class Hash
    {
        public Hash()
        { }

        #region Hash Choices
        /// <summary>The wanted hash function.</summary>
        public enum HashType : int
        {
            /// <summary>MD5 Hashing</summary>
            MD5,
            /// <summary>SHA1 Hashing</summary>
            SHA1,
            /// <summary>SHA256 Hashing</summary>
            SHA256,
            /// <summary>SHA384 Hashing</summary>
            SHA384,
            /// <summary>SHA512 Hashing</summary>
            SHA512
        } /* HashType */
        #endregion

        #region Public Methods
        /// <summary>Generates the hash of a text.</summary>
        /// <param name="strPlain">The text of which to generate a hash of.</param>
        /// <param name="hshType">The hash function to use.</param>
        /// <returns>The hash as a hexadecimal string.</returns>
        public static string GetHash(string strPlain, HashType hshType)
        {
            string strRet;
            switch (hshType)
            {
                case HashType.MD5:
                    strRet = GetMD5(strPlain);
                    break;
                case HashType.SHA1:
                    strRet = GetSHA1(strPlain);
                    break;
                case HashType.SHA256:
                    strRet = GetSHA256(strPlain);
                    break;
                case HashType.SHA384:
                    strRet = GetSHA384(strPlain);
                    break;
                case HashType.SHA512:
                    strRet = GetSHA512(strPlain);
                    break;
                default:
                    strRet = "Invalid HashType";
                    break;
            }
            return strRet;
        } /* GetHash */

        /// <summary>Checks a text with a hash.</summary>
        /// <param name="strOriginal">The text to compare the hash against.</param>
        /// <param name="strHash">The hash to compare against.</param>
        /// <param name="hshType">The type of hash.</param>
        /// <returns>True if the hash validates, false otherwise.</returns>
        public static bool CheckHash(string strOriginal, string strHash, HashType hshType)
        {
            string strOrigHash = GetHash(strOriginal, hshType);
            return (strOrigHash == strHash);
        } /* CheckHash */
        #endregion

        #region Hashers
        private static string GetMD5(string strPlain)
        {
            UnicodeEncoding UE = new UnicodeEncoding();
            byte[] HashValue, MessageBytes = UE.GetBytes(strPlain);
            MD5 md5 = new MD5CryptoServiceProvider();
            string strHex = "";

            HashValue = md5.ComputeHash(MessageBytes);
            foreach (byte b in HashValue)
            {
                strHex += String.Format("{0:x2}", b);
            }
            return strHex;
        } /* GetMD5 */

        private static string GetSHA1(string strPlain)
        {
            UnicodeEncoding UE = new UnicodeEncoding();
            byte[] HashValue, MessageBytes = UE.GetBytes(strPlain);
            SHA1Managed SHhash = new SHA1Managed();
            string strHex = "";

            HashValue = SHhash.ComputeHash(MessageBytes);
            foreach (byte b in HashValue)
            {
                strHex += String.Format("{0:x2}", b);
            }
            return strHex;
        } /* GetSHA1 */

        private static string GetSHA256(string strPlain)
        {
            UnicodeEncoding UE = new UnicodeEncoding();
            byte[] HashValue, MessageBytes = UE.GetBytes(strPlain);
            SHA256Managed SHhash = new SHA256Managed();
            string strHex = "";

            HashValue = SHhash.ComputeHash(MessageBytes);
            foreach (byte b in HashValue)
            {
                strHex += String.Format("{0:x2}", b);
            }
            return strHex;
        } /* GetSHA256 */

        private static string GetSHA384(string strPlain)
        {
            UnicodeEncoding UE = new UnicodeEncoding();
            byte[] HashValue, MessageBytes = UE.GetBytes(strPlain);
            SHA384Managed SHhash = new SHA384Managed();
            string strHex = "";

            HashValue = SHhash.ComputeHash(MessageBytes);
            foreach (byte b in HashValue)
            {
                strHex += String.Format("{0:x2}", b);
            }
            return strHex;
        } /* GetSHA384 */

        private static string GetSHA512(string strPlain)
        {
            UnicodeEncoding UE = new UnicodeEncoding();
            byte[] HashValue, MessageBytes = UE.GetBytes(strPlain);
            SHA512Managed SHhash = new SHA512Managed();
            string strHex = "";

            HashValue = SHhash.ComputeHash(MessageBytes);
            foreach (byte b in HashValue)
            {
                strHex += String.Format("{0:x2}", b);
            }
            return strHex;
        } /* GetSHA512 */
        #endregion
    }
}

Battery

1. For lithium ion batteries, you do not need to discharge them fully and recharge constantly. Since they don’t have the same "memory" as older nickel-metal hydride batteries, it is actually better to discharge a lithium ion only partially (10 to 20%) before recharging. You need to do a full discharge only about every 30 charges (usually around every 2 to 3 weeks).
2. Consider taking your battery out when using your laptop plugged into AC power. Just make sure to keep the contacts clean. If you need to clean them, use a lint-free cloth moistened with rubbing alcohol every couple of months.

Software & Hardware

1. Defrag your hard drive regularly
2. Dim your screen to the lowest level you can tolerate
3. Close unused programs running in the background
4. Disable WIFI when not in use.
5. Hibernate your computer, not standby.

Environment

1. Avoid propping your laptop on a pillow, blanket, or other soft surface that can heat up or block cooling fans.
2. Clean your desk. It sounds strange, but if you have a dusty, dirty desk, that dust will get into the vents and clog the cooling fan. Once the dust is inside your laptop, it is much harder to remove. You can try blasting it out with canned air, but you run the risk of damaging internal components. You can also remove the vent and clean out the grit, but remember that taking apart your laptop can void the warranty. So clean your desk at least once a week, if not daily.
3. Try not to store your laptop in a place where the air temperature exceeds 80 degrees Fahrenheit, such as a hot car or an outdoor patio. And if your laptop heats up or is cold, let it return to room temperature before starting up.
4. Use a cooling pad when using a notebook computer on your lap.

By default the ASPNET user cannot access the existing eventlogs categories. To resolve this, you must set the permissions in the Eventlog key in the registry:

1. Launch RegEdit.
2. Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\EventLog\.
3. From the menu, select Edit->Permissions.
4. Click the Add button and write ASPNET (if ASP.NET is running under a different User ID, use that ID instead).
5. Click OK.
6. Select the newly added user from the list (ASP.NET Machine User by default).
7. Click on Full Control in the Allow column. 8. Click OK.

More info here.