https://stackoverflow.com/q/52544461/1187415

SecureCoding.swift

import Foundation

@objcMembers class ClassA: NSObject, NSSecureCoding {
	var title: String
	
	init(title: String) {
		self.title = title
	}

	func encode(with aCoder: NSCoder) {
		aCoder.encode(self.title, forKey: "title")
	}
	
	required init?(coder aDecoder: NSCoder) {
		guard let title = aDecoder.decodeObject(of: NSString.self, forKey: "title") as String? else {
			return nil
		}
		self.title = title
	}
	
	public class var supportsSecureCoding: Bool { return true }
}

@objcMembers class ClassB: ClassA {
	var name: String
	init(name: String, title: String) {
		self.name = name
		super.init(title: title)
	}
	
	override func encode(with aCoder: NSCoder) {
		aCoder.encode(self.name, forKey: "name")
		super.encode(with: aCoder)
	}
	
	required init?(coder aDecoder: NSCoder) {
		guard let name = aDecoder.decodeObject(of: NSString.self, forKey: "name") as String? else {
			return nil
		}
		self.name = name
		super.init(coder: aDecoder)
	}
	
	//override public class var supportsSecureCoding: Bool { return true }
	static private var secureCoding = true
	override public class var supportsSecureCoding: Bool { return secureCoding }
}

do {
	let obj = ClassB(name: "NAME", title: "TITLE")
	let data = NSKeyedArchiver.archivedData(withRootObject: obj)
	
	let ua = NSKeyedUnarchiver(forReadingWith: data)
	ua.requiresSecureCoding = true
	
	if let other = ua.decodeObject(of: ClassB.self, forKey: NSKeyedArchiveRootObjectKey) {
		print(other.name, other.title)
	}
}