Migrate to ASP.Net Identity

SqlPasswordHasher.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using Microsoft.AspNet.Identity;

namespace MySite.Business.Identity
{
    public class SqlPasswordHasher : PasswordHasher
    {
        public override string HashPassword(string password)
        {
            return base.HashPassword(password);
        }

        public override PasswordVerificationResult VerifyHashedPassword(string hashedPassword, string providedPassword)
        {
            string[] passwordProperties = hashedPassword.Split('|');
            if (passwordProperties.Length != 3)
            {
                return base.VerifyHashedPassword(hashedPassword, providedPassword);
            }
            else
            {
                string passwordHash = passwordProperties[0];
                int passwordformat = 1;
                string salt = passwordProperties[2];
                if (String.Equals(EncryptPassword(providedPassword, passwordformat, salt), passwordHash,
                    StringComparison.CurrentCultureIgnoreCase))
                {
                    return PasswordVerificationResult.SuccessRehashNeeded;
                }
                else
                {
                    return PasswordVerificationResult.Failed;
                }
            }
        }

        private string EncryptPassword(string pass, int passwordFormat, string salt)
        {
            if (passwordFormat == 0)
                return pass;

            var bPassword = Encoding.Unicode.GetBytes(pass);
            var bSalt = Convert.FromBase64String(salt);
            byte[] bRet = null;

            if (passwordFormat != 1) return Convert.ToBase64String(bRet);

            var hashAlgorithm = HashAlgorithm.Create("HMACSHA512");

            if (hashAlgorithm is KeyedHashAlgorithm)
            {
                var keyedHashAlgorithm = (KeyedHashAlgorithm)hashAlgorithm;
                if (keyedHashAlgorithm.Key.Length == bSalt.Length)
                {
                    keyedHashAlgorithm.Key = bSalt;
                }
                else if (keyedHashAlgorithm.Key.Length < bSalt.Length)
                {
                    var bKey = new byte[keyedHashAlgorithm.Key.Length];
                    Buffer.BlockCopy(bSalt, 0, bKey, 0, bKey.Length);
                    keyedHashAlgorithm.Key = bKey;
                }
                else
                {
                    var bKey = new byte[keyedHashAlgorithm.Key.Length];
                    for (var iter = 0; iter < bKey.Length;)
                    {
                        var len = Math.Min(bSalt.Length, bKey.Length - iter);
                        Buffer.BlockCopy(bSalt, 0, bKey, iter, len);
                        iter += len;
                    }
                    keyedHashAlgorithm.Key = bKey;
                }
                bRet = keyedHashAlgorithm.ComputeHash(bPassword);
            }
            else
            {
                byte[] bAll = new byte[bSalt.Length + bPassword.Length];
                Buffer.BlockCopy(bSalt, 0, bAll, 0, bSalt.Length);
                Buffer.BlockCopy(bPassword, 0, bAll, bSalt.Length, bPassword.Length);
                bRet = hashAlgorithm.ComputeHash(bAll);
            }
            return Convert.ToBase64String(bRet);
        }
    }
}