MD5, SHA1, SHA256 and SHA512 Hash Algorithm Functions in C#

One of the great problems I have had with OO languages such as .NET and Java is that some tasks, that are as simple as calling a function in other languages, are complicated to no end. One such problem is with the different hash functions in .NET available via System.Security.Cryptography. In PHP if I need to get the MD5 of a string I simply call the built in MD5 function. In .NET I need to build my own MD5 function using System.Security.Cryptography and that, even though I understand why it is the way it is, can get a little annoying after a while. I have taken the liberty of simplifying this process by creating a HASH class that can be plugged into your programs as either a new class or by creating a hash.dll of out of it. The code lets you call MD5, SHA1, SHA256 and SHA512 functions and takes care of the process for you.

using System;
using System.Security.Cryptography;
using System.Text;

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

        public enum HashType : int
        {
            MD5,
            SHA1,
            SHA256,
            SHA512
        }

        public static string GetHash(string text, HashType hashType)
        {
            string hashString;
            switch (hashType)
            {
                case HashType.MD5: 
                    hashString = GetMD5(text); 
                    break;
                case HashType.SHA1: 
                    hashString = GetSHA1(text); 
                    break;
                case HashType.SHA256:
                    hashString = GetSHA256(text);
                    break;
                case HashType.SHA512:
                    hashString = GetSHA512(text);
                    break;
                default: 
                    hashString = "Invalid Hash Type"; 
                    break;
            }
            return hashString;
        }
        
        public static bool CheckHash(string original, string hashString, HashType hashType)
        {
            string originalHash = GetHash(original, hashType);
            return (originalHash == hashString);
        }

        private static string GetMD5(string text)
        {
            UnicodeEncoding UE = new UnicodeEncoding();
            byte[] hashValue;
            byte[] message = UE.GetBytes(text);

            MD5 hashString = new MD5CryptoServiceProvider();
            string hex = "";

            hashValue = hashString.ComputeHash(message);
            foreach (byte x in hashValue)
            {
                hex += String.Format("{0:x2}", x);
            }
            return hex;
        }

        private static string GetSHA1(string text)
        {
            UnicodeEncoding UE = new UnicodeEncoding();
            byte[] hashValue;
            byte[] message = UE.GetBytes(text);

            SHA1Managed hashString = new SHA1Managed();
            string hex = "";

            hashValue = hashString.ComputeHash(message);
            foreach (byte x in hashValue)
            {
                hex += String.Format("{0:x2}", x);
            }
            return hex;
        }

        private static string GetSHA256(string text)
        {
            UnicodeEncoding UE = new UnicodeEncoding();
            byte[] hashValue;
            byte[] message = UE.GetBytes(text);
            
            SHA256Managed hashString = new SHA256Managed();
            string hex = "";

            hashValue = hashString.ComputeHash(message);
            foreach (byte x in hashValue)
            {
                hex += String.Format("{0:x2}", x);
            }
            return hex;
        }

        private static string GetSHA512(string text)
        {
            UnicodeEncoding UE = new UnicodeEncoding();
            byte[] hashValue;
            byte[] message = UE.GetBytes(text);
            
            SHA512Managed hashString = new SHA512Managed();
            string hex = "";

            hashValue = hashString.ComputeHash(message);
            foreach (byte x in hashValue)
            {
                hex += String.Format("{0:x2}", x);
            }
            return hex;
        }
    }
}

Use the GetHash(string,HashType) method in your code to retrieve the hash value of your string, passing in the string and hash type you wish to use. To compare a string and a stored hash value use the CheckHash(string,string,HashType) method, passing in the original string, stored hash string and hash type.

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