How to get a equal hash to the FormsAuthentication.HashPasswordForStoringInConfigFile("asdf", "MD5") method?

Question

Looking for a method or to be pointed in the right direction so I can return an hash equal to the hash returned by FormsAuthentication.HashPasswordForStoringInConfigFile("asdf", "MD5"). I've been trying code like:

        ASCIIEncoding encoding = new ASCIIEncoding();
        encoding.GetBytes("asdf");

        var hashedBytes = MD5.Create().ComputeHash(bytes);
        var password = encoding.GetString(hashedBytes);

I'm not that strong on Hashing so I don't know where to go next. I always end up with crazy special characters while the FormsAuth method always returns something readable.

Just trying to remove the external dependency to FormAuthentication from some internal business classes.

Answer 1

Here is the reflector's output:

Your problem is not using UTF8

public static string HashPasswordForStoringInConfigFile(string password, string passwordFormat)
{
    HashAlgorithm algorithm;
    if (password == null)
    {
        throw new ArgumentNullException("password");
    }
    if (passwordFormat == null)
    {
        throw new ArgumentNullException("passwordFormat");
    }
    if (StringUtil.EqualsIgnoreCase(passwordFormat, "sha1"))
    {
        algorithm = SHA1.Create();
    }
    else
    {
        if (!StringUtil.EqualsIgnoreCase(passwordFormat, "md5"))
        {
            throw new ArgumentException(SR.GetString("InvalidArgumentValue", new object[] { "passwordFormat" }));
        }
        algorithm = MD5.Create();
    }
    return MachineKeySection.ByteArrayToHexString(algorithm.ComputeHash(Encoding.UTF8.GetBytes(password)), 0);
}

So here is your updated code:

    encoding.GetBytes("asdf");

    var hashedBytes = MD5.Create().ComputeHash(bytes);
    var password = Encoding.UTF8.GetString(hashedBytes);

Answer 2

After some Googling, I changed @Pieter's code to make it independent of the System.Web

return string.Join("",
  new MD5CryptoServiceProvider().ComputeHash(
    new MemoryStream(Encoding.UTF8.GetBytes(password))).Select(x => x.ToString("X2")));