Pbkdf1.cs

using System;
using System.Collections.Generic;
using System.Text;
 
namespace Waher.Security.PKCS.Passwords
{
    public abstract class Pbkdf1 : PasswordEncryption
    {
        private readonly byte[] salt;
        private readonly byte[] key;
        private readonly int iterations;
 
        public Pbkdf1(string Password, int Iterations, int KeyLength, HashFunction HashFunction)
            : base(Password)
        {
            if (Iterations <= 0)
                throw new ArgumentException("Must be postitive.", nameof(Iterations));
 
            if (KeyLength <= 0)
                throw new ArgumentException("Must be postitive.", nameof(Iterations));
 
            this.iterations = Iterations;
            this.salt = PfxEncoder.GetRandomBytes(8);
 
            byte[] Bin = Hashes.ComputeHash(HashFunction, 
                Primitives.CONCAT(Encoding.UTF8.GetBytes(Password), this.salt));
 
            while (--Iterations >= 0)
                Bin = Hashes.ComputeHash(HashFunction, Bin);
 
            if (KeyLength > Bin.Length)
                throw new ArgumentException("Derived key too long.", nameof(KeyLength));
 
            this.key = new byte[KeyLength];
 
            Array.Copy(Bin, 0, this.key, 0, KeyLength);
        }
    }
}