How To Customize Password Hashing in ASP.Net Identity

You create an encrypt method to encrypt your password

There are many ways to encrypt passwords, within the scope of this article I will use MD5 to hash a string

Creating an Encrypt class, then create a method allows you to input a string, then encrypt it

public class Encrypt
{
    public static string GetMD5Hash(string input)
    {
        //using md5 to hash string
        using (MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider())
        {
            //convert string to byte arrays
            byte[] bs = System.Text.Encoding.UTF8.GetBytes(input);
            bs = md5.ComputeHash(bs);//Hash byte
            System.Text.StringBuilder s = new System.Text.StringBuilder();
            //convert byte arrays to string
            foreach (byte b in bs)
                s.Append(b.ToString("x2").ToLower());
            return s.ToString();
        }
    }
}

You need to create a CustomPasswordHasher class then implement IPasswordHasher and add a custom encrypt string to the HashPassword method.

public class CustomPasswordHasher : IPasswordHasher
{
    public string HashPassword(string password)
    {
        return Encrypt.GetMD5Hash(password);//using custom hash password
    }

    public PasswordVerificationResult VerifyHashedPassword(string hashedPassword, string providedPassword)
    {
        if (hashedPassword == HashPassword(providedPassword))
            return PasswordVerificationResult.Success;
        else
            return PasswordVerificationResult.Failed;
    }
}

Open the IdentityConfig.cs then modify code as below to implement custom password

public ApplicationUserManager(IUserStore<ApplicationUser> store)
            : base(store)
{
    PasswordHasher = new CustomPasswordHasher();
}

I hope you can solve your problem with custom membership password hasher base on MD5 encrypt in ASP.NET Identity