c# - Rfc2898DeriveBytes 如何验证作为哈希值存储在数据库中的密码

Question

如何验证以哈希值形式存储在数据库中的密码

当我使用数据库值验证密码哈希时，它永远不会相同，因为它会生成随机盐。

如何添加盐以验证和测试。

下面是我用于散列和验证散列密码的代码。

我的代码:

/// <summary>
        /// Generate the value from bytes.
        /// </summary>
        /// <param name="password"></param>
        /// <param name="iterationCount"></param>
        /// <returns></returns>
        private static string GenerateHashValue(string password)
        {
            return Convert.ToBase64String(GenerateHashBytes(password));
        }

        /// <summary>
        /// Hashing the password using PBKDF2
        /// </summary>
        /// <param name="password"></param>
        /// <param name="iterationCount"></param>
        /// <returns></returns>
        private static byte[] GenerateHashBytes(string password)
        {
            byte[] hashValue;
            //create salt
            byte[] salt = GenerateRandomSalt();
            var valueToHash = string.IsNullOrEmpty(password) ? string.Empty : password;
            using (var pbkdf2 = new Rfc2898DeriveBytes(valueToHash,salt, iterationCount))
            {
                hashValue = pbkdf2.GetBytes(DerivedKeyLength); 
            }
            return hashValue;
        }

        public static bool VerifyPassword(string password, string correctHash)
        {
            byte[] hash;
            byte[] OriginalHash = Encoding.ASCII.GetBytes(correctHash);
            hash = GenerateHashBytes(password); 
            return SlowEquals(hash, OriginalHash);
        }

        private static bool SlowEquals(byte[] a, byte[] b)
        {
            var diff = (uint)a.Length ^ (uint)b.Length;
            for (int i = 0; i < a.Length && i < b.Length; i++)
            {
                diff |= (uint)(a[i] ^ b[i]);
            }
            return diff == 0;
        }

        /// <summary>
        /// Used to generate the random string to append hash.
        /// </summary>
        /// <returns></returns>
        private static byte[] GenerateRandomSalt()
        {
            /*We are using the RNGCryptoServiceProvider class to create a Cryptography Secure Pseudo-Random Number Generator that will generate the level of randomness and uniqueness we require for a salt.*/
            var csprng = new RNGCryptoServiceProvider();
            var salt = new byte[SaltByteLength];
            csprng.GetBytes(salt);
            return salt;
        }

Answer 1

您必须创建一个盐并将其与密码哈希一起存储在您的数据库中。

在对密码进行哈希处理后，您从数据库中为用户 X(或其他任何人)请求加盐，检查它是否存在，然后将加盐应用于您的哈希。

它看起来像这样(带有您提供的一些代码的伪代码):

var salt = GetSaltFromDB();
if (salt == null) //Not yet in DB
    salt = GenerateSalt(); //This also saves the salt to DB
using (var pbkdf2 = new Rfc2898DeriveBytes(valueToHash, salt, iterationCount))
{
    hashValue = pbkdf2.GetBytes(DerivedKeyLength); 
}