One-way-Verschlüsselung Methoden

Dass Sie im Grunde wollen, verwenden Sie entweder MD5 oder SHA-256. Ach, und zur info, wenn es einen Weg, es heißt hash. In der MSDN-Dokumentation deckt sowohl hashes ausgiebig.

Für alle neuen Besucher auf diese Frage, crackstation.net hat eine vollständige .NET-Implementierung an der Unterseite, zusammen mit einer ziemlich ausführlichen Erklärung, was Sie tun sollten und wie es funktioniert

Wird der folgende code kopiert, ohne änderungen aus crackstation.net

/* 
 * Password Hashing With PBKDF2 (http://crackstation.net/hashing-security.htm).
 * Copyright (c) 2013, Taylor Hornby
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, 
 * this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation 
 * and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
 * POSSIBILITY OF SUCH DAMAGE.
 */

using System;
using System.Text;
using System.Security.Cryptography;

namespace PasswordHash
{
    ///<summary>
    ///Salted password hashing with PBKDF2-SHA1.
    ///Author: havoc AT defuse.ca
    ///www: http://crackstation.net/hashing-security.htm
    ///Compatibility: .NET 3.0 and later.
    ///</summary>
    public class PasswordHash
    {
        //The following constants may be changed without breaking existing hashes.
        public const int SALT_BYTE_SIZE = 24;
        public const int HASH_BYTE_SIZE = 24;
        public const int PBKDF2_ITERATIONS = 1000;

        public const int ITERATION_INDEX = 0;
        public const int SALT_INDEX = 1;
        public const int PBKDF2_INDEX = 2;

        ///<summary>
        ///Creates a salted PBKDF2 hash of the password.
        ///</summary>
        ///<param name="password">The password to hash.</param>
        ///<returns>The hash of the password.</returns>
        public static string CreateHash(string password)
        {
            //Generate a random salt
            RNGCryptoServiceProvider csprng = new RNGCryptoServiceProvider();
            byte[] salt = new byte[SALT_BYTE_SIZE];
            csprng.GetBytes(salt);

            //Hash the password and encode the parameters
            byte[] hash = PBKDF2(password, salt, PBKDF2_ITERATIONS, HASH_BYTE_SIZE);
            return PBKDF2_ITERATIONS + ":" +
                Convert.ToBase64String(salt) + ":" +
                Convert.ToBase64String(hash);
        }

        ///<summary>
        ///Validates a password given a hash of the correct one.
        ///</summary>
        ///<param name="password">The password to check.</param>
        ///<param name="correctHash">A hash of the correct password.</param>
        ///<returns>True if the password is correct. False otherwise.</returns>
        public static bool ValidatePassword(string password, string correctHash)
        {
            //Extract the parameters from the hash
            char[] delimiter = { ':' };
            string[] split = correctHash.Split(delimiter);
            int iterations = Int32.Parse(split[ITERATION_INDEX]);
            byte[] salt = Convert.FromBase64String(split[SALT_INDEX]);
            byte[] hash = Convert.FromBase64String(split[PBKDF2_INDEX]);

            byte[] testHash = PBKDF2(password, salt, iterations, hash.Length);
            return SlowEquals(hash, testHash);
        }

        ///<summary>
        ///Compares two byte arrays in length-constant time. This comparison
        ///method is used so that password hashes cannot be extracted from
        ///on-line systems using a timing attack and then attacked off-line.
        ///</summary>
        ///<param name="a">The first byte array.</param>
        ///<param name="b">The second byte array.</param>
        ///<returns>True if both byte arrays are equal. False otherwise.</returns>
        private static bool SlowEquals(byte[] a, byte[] b)
        {
            uint 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>
        ///Computes the PBKDF2-SHA1 hash of a password.
        ///</summary>
        ///<param name="password">The password to hash.</param>
        ///<param name="salt">The salt.</param>
        ///<param name="iterations">The PBKDF2 iteration count.</param>
        ///<param name="outputBytes">The length of the hash to generate, in bytes.</param>
        ///<returns>A hash of the password.</returns>
        private static byte[] PBKDF2(string password, byte[] salt, int iterations, int outputBytes)
        {
            Rfc2898DeriveBytes pbkdf2 = new Rfc2898DeriveBytes(password, salt);
            pbkdf2.IterationCount = iterations;
            return pbkdf2.GetBytes(outputBytes);
        }
    }
}

Ein paar Dinge beachten:

• Die original-Beitrag und OWASP-Richtlinien beide vorschlagen, die Stärkung der Verschlüsselung mittels HMAC
• Iteration zählen in der oben genannten Umsetzung ist wahrscheinlich ein wenig niedrig. OWASP und diese Antwort empfehlen eine self-balancing work load
• Salz Größe in der Umsetzung oben 24 aber wenn ich lese diese Antwort korrekt sollte es nicht gehen, über 20. Das heißt, ich bin alles andere als ein Experte in Kryptographie, also kann ich nicht wirklich sagen, ob diese Behauptung wahr oder falsch ist