PbePkcs12.cs

using System;
using System.Collections.Generic;
using System.Text;
 
namespace Waher.Security.PKCS.Passwords
{
    public abstract class PbePkcs12 : PasswordEncryption
    {
        private readonly byte[] salt;
        private readonly byte[] key;
        private readonly int iterations;
 
        public PbePkcs12(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);
 
            this.key = PfxEncoder.PRF(HashFunction, Iterations,
                PfxEncoder.FormatPassword(Password), this.salt, KeyLength, 1);
        }
 
        protected byte[] Key => this.key;
 
        protected int Iterations => this.iterations;
 
        protected byte[] Salt => this.salt;
 
        public override void EncodePkcs5AlgorithmIdentifier(DerEncoder Der)
        {
            Der.StartSEQUENCE();
            Der.OBJECT_IDENTIFIER(this.AlgorithmOID);
            Der.StartSEQUENCE();            // pkcs-12PbeParams
            Der.OCTET_STRING(this.salt);
            Der.INTEGER(this.iterations);
            Der.EndSEQUENCE();              // End of pkcs-12PbeParams
            Der.EndSEQUENCE();
        }
 
    }
}