PasswordHasher 算法

         public override PasswordVerificationResult VerifyHashedPassword(string hashedPassword, string providedPassword)
         {
             string[] passwordProperties = hashedPassword.Split('|');
             if (passwordProperties.Length != )
             {
                 return base.VerifyHashedPassword(hashedPassword, providedPassword);
             }
             else
             {
                 string passwordHash = passwordProperties[];
                 int passwordformat = ;
                 string salt = passwordProperties[];
                 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 == ) 
                 return pass;

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

             if (passwordFormat == )
             { // MembershipPasswordFormat.Hashed
                 HashAlgorithm hm = HashAlgorithm.Create("SHA1");
                 if (hm is KeyedHashAlgorithm)
                 {
                     KeyedHashAlgorithm kha = (KeyedHashAlgorithm)hm;
                     if (kha.Key.Length == bSalt.Length)
                     {
                         kha.Key = bSalt;
                     }
                     else if (kha.Key.Length < bSalt.Length)
                     {
                         byte[] bKey = new byte[kha.Key.Length];
                         Buffer.BlockCopy(bSalt, , bKey, , bKey.Length);
                         kha.Key = bKey;
                     }
                     else
                     {
                         byte[] bKey = new byte[kha.Key.Length];
                         for (int iter = ; iter < bKey.Length; )
                         {
                             int len = Math.Min(bSalt.Length, bKey.Length - iter);
                             Buffer.BlockCopy(bSalt, , bKey, iter, len);
                             iter += len;
                         }
                         kha.Key = bKey;
                     }
                     bRet = kha.ComputeHash(bIn);
                 }
                 else
                 {
                     byte[] bAll = new byte[bSalt.Length + bIn.Length];
                     Buffer.BlockCopy(bSalt, , bAll, , bSalt.Length);
                     Buffer.BlockCopy(bIn, , bAll, bSalt.Length, bIn.Length);
                     bRet = hm.ComputeHash(bAll);
                 }
             }

             return Convert.ToBase64String(bRet);
         }