SecurityInitialization.cs

using System;
using OSDP.Net.Messages;
using OSDP.Net.Messages.SecureChannel;
 
namespace OSDP.Net.Model.CommandData;
 
internal class SecurityInitialization : CommandData
{
    public SecurityInitialization(byte[] serverRandomNumber, bool isDefaultKey)
    {
        ServerRandomNumber = serverRandomNumber ?? throw new ArgumentNullException(nameof(serverRandomNumber));
        IsDefaultKey = isDefaultKey;
    }
    
    public byte[] ServerRandomNumber { get; }
    
    public bool IsDefaultKey { get; }
    
    public override CommandType CommandType => CommandType.SessionChallenge;

    public override byte Code => (byte)CommandType;
    
    public override bool IsSecurityInitialization => true;
        
    public override ReadOnlySpan<byte> SecurityControlBlock()
    {
        return new byte[]
        {
            0x03,
            (byte)SecurityBlockType.BeginNewSecureConnectionSequence,
            (byte)(IsDefaultKey ? 0x00 : 0x01)
        };
    }

    public override byte[] BuildData()
    {
        return ServerRandomNumber;
    }

    public static SecurityInitialization ParseData(ReadOnlySpan<byte> data, ReadOnlySpan<byte> securityControlBlock)
    {
        return new SecurityInitialization(data.ToArray(), securityControlBlock[2] == 0x01);
    }
}