How to generate MD5 Hash(32/64 Characters) from an integer

Question

I have Googled and checked

How to generate MD5 Hash(32/64 Characters) from an integer?

What I got is there are examples for generating an MD5 hash string from a string or from a byte array. But in my case, I need to getthe MD5 hash of an integer.

I know that the GetHashCode() method is there to get the hash code for an integer. But this method is not applicable in my case.

Do I need to convert the integer to a string or byte array to get the expected MD5 hash string?

Answer 1

If you want to know what is the md5 hash of "meaning of life" you can

int meaningOfLife = 42;
var result = CalculateMD5Hash(""+meaningOfLife);

This assumes you can

public string CalculateMD5Hash(string input)
{
    // step 1, calculate MD5 hash from input
    MD5 md5 = System.Security.Cryptography.MD5.Create();
    byte[] inputBytes = System.Text.Encoding.ASCII.GetBytes(input);
    byte[] hash = md5.ComputeHash(inputBytes);

    // step 2, convert byte array to hex string
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < hash.Length; i++)
    {
        sb.Append(hash[i].ToString("X2"));
    }
    return sb.ToString();
}

Answer 2

First you need to convert your integer into a byte array then you can do this:

byte[] hashValue;
using (var md5 = MD5.Create())
{
    hashValue = md5.ComputeHash(BitConverter.GetBytes(5));
}

Answer 3

You can try this,

int intValue = ; // your value
byte[] intBytes = BitConverter.GetBytes(intValue);
Array.Reverse(intBytes);
byte[] result = intBytes; // you are most probably working on a little-endian machine
byte[] hash = ((HashAlgorithm) CryptoConfig.CreateFromName("MD5")).ComputeHash(result);

// string representation (similar to UNIX format)
string encoded = BitConverter.ToString(hash)
   // without dashes
   .Replace("-", string.Empty)
   // make lowercase
   .ToLower();

Answer 4

Thank you All.After referring all the answers, here i am posting my answer which is containg Generic methods for Generating "MD5 Hash(32/64 Characters) from an integer/string/byte array". Might be helpful for others.

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

namespace ConvertIntToHashCodeConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            int number = 100;
            Console.WriteLine(GetHashMD5(number.ToString()));
            Console.WriteLine(GetHashStringFromInteger(number));
            Console.Read();
        }
        /// <summary>
        /// Get the Hash Value for MD5 Hash(32 Characters) from an integer
        /// </summary>
        /// <param name="number"></param>
        /// <returns></returns>
        public static string GetHashStringFromInteger(int number)
        {
            string hash;
            using (var md5 = System.Security.Cryptography.MD5.Create())
            {
                hash = String.Concat(md5.ComputeHash(BitConverter
                  .GetBytes(number))
                  .Select(x => x.ToString("x2")));
            }
            return hash;
        }

        /// <summary>
        /// Get the Hash Value for sha256 Hash(64 Characters)
        /// </summary>
        /// <param name="data">The Input Data</param>
        /// <returns></returns>
        public static string GetHash256(string data)
        {
            string hashResult = string.Empty;

            if (data != null)
            {
                using (SHA256 sha256 = SHA256Managed.Create())
                {
                    byte[] dataBuffer = Encoding.UTF8.GetBytes(data);
                    byte[] dataBufferHashed = sha256.ComputeHash(dataBuffer);
                    hashResult = GetHashString(dataBufferHashed);
                }
            }
            return hashResult;
        }

        /// <summary>
        /// Get the Hash Value for MD5 Hash(32 Characters)
        /// </summary>
        /// <param name="data">The Input Data</param>
        /// <returns></returns>
        public static string GetHashMD5(string data)
        {
            string hashResult = string.Empty;
            if (data != null)
            {
                using (MD5 md5 = MD5.Create())
                {
                    byte[] dataBuffer = Encoding.UTF8.GetBytes(data);
                    byte[] dataBufferHashed = md5.ComputeHash(dataBuffer);
                    hashResult = GetHashString(dataBufferHashed);
                }
            }
            return hashResult;
        }
        /// <summary>
        /// Get the Encrypted Hash Data
        /// </summary>
        /// <param name="dataBufferHashed">Buffered Hash Data</param>
        /// <returns> Encrypted hash String </returns>
        private static string GetHashString(byte[] dataBufferHashed)
        {
            StringBuilder sb = new StringBuilder();
            foreach (byte b in dataBufferHashed)
            {
                sb.Append(b.ToString("X2"));
            }
            return sb.ToString();
        }
    }
}

Modify / any better solution for this code is always welcome.