.net, C#, Code, Microsoft, Security, Technical

Quickly calculate and compare MD5 or SHA2 values

There might be situations when you might want to quickly calculate the MD5 or SHA2  values of any file or a set of files. The solution depends on what is your requirement: 1) Its a one time work and you would just want the results in a text / html file 2) You want the hash inside your .Net program

Scenario 1: The best bet is to download a program called HashMyFiles by nirsoft.net
This nifty little program can generate an HTML report containing the hashes of all the files in the specified file/folder.

Scenario 2: Here is the C# version of creating the hashes using the build in Cryptography classes.

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

public string GetMD5(string filePath)
{
            StringBuilder sb = new StringBuilder();
            FileStream fs = new FileStream(file, FileMode.Open);
            MD5 md5 = new MD5CryptoServiceProvider();
            byte[] hash = md5.ComputeHash(fs);
            fs.Close();
            fs.Dispose();
            foreach (byte hex in hash)
            {
                //Returns hash in lower case.
                //To return upper case change “x2” to “X2”
                sb.Append(hex.ToString(“x2”));
            }
            return sb.ToString();
}

public string GetSHA2(string filePath)
{
            StringBuilder sb = new StringBuilder();
            FileStream fs = new FileStream(file, FileMode.Open);
            SHA256 s2 = new SHA256CryptoServiceProvider();
            byte[] hash = s2.ComputeHash(fs);
            fs.Close();
            fs.Dispose();
            foreach (byte hex in hash)
            {
                //Returns hash in lower case.
                //To return upper case change “x2” to “X2”
                sb.Append(hex.ToString(“x2”));
            }
            return sb.ToString();
}