Module pbd::dtc

Background

The practice of implementing Data Tracker Chains addresses the following Privacy Design Strategies:

• Inform
• Control
• Demonstrate

Whenever data is passed through Actors (e.g.: data collection between an online portal and the backend service to order the product), it is important to ensure that data lineage is tracked and retained.

A privacy engineering practice that supports the real-time recording of data lineage is to implement a Data Tracking Chain that lives with the data.

Usage

Whenever the data is touched by a processor or landed in a location, we have the Tracker add a Marker its MarkerChain.

extern crate pbd;
 
use pbd::dtc::Tracker;
 
fn main() {
    let mut tracker = Tracker::new("purchaseId=12345".to_string());
    tracker.add(1578071239, "payment-validator".to_string(), "purchaseId=12345".to_string());
    tracker.add(1578071245, "credit-card-transaction-processor".to_string(), "purchaseId=12345".to_string());
 
    println!("{}", tracker.serialize());
}

---

We can ensure that the MarkerChain has been tampered with outside of the Tracker's control (e.g.: tracker.serialize() => change the JSON => Tracker::from_serialize()) by calling the is_valid() method.

extern crate pbd;
extern crate json;
 
use pbd::dtc::{Marker, Tracker};
 
fn main() {
    let mut tracker = Tracker::new("purchaseId=12345".to_string());
    tracker.add(1578071239, "payment-validator".to_string(), "purchaseId=12345".to_string());
    tracker.add(1578071245, "credit-card-transaction-processor".to_string(), "purchaseId=12345".to_string());
     
    let mut markerchain: Vec<Marker> = serde_json::from_str(&tracker.serialize()).unwrap();
    markerchain[1].identifier.actor_id = "tampered data".to_string();
    let serialized = serde_json::to_string(&markerchain).unwrap();
    let tracker_tampered = Tracker::from_serialized(&serialized).unwrap();
     
    assert_eq!(Tracker::is_valid(&tracker_tampered), false);
}

---

We can also ensure that Data Tracker Chains are passed when working with RESTful APIs by implementing the middleware and extractor modules.

Modules

error	Data Tracker Chain specific Errors
extractor	An Extractor that parses the HTTP header and pulls out the Data Tracker Chain
middleware	Middleware for ensuring a Data Tracker Chain is present and valid

Structs

Marker	Represents a Marker
MarkerIdentifier	Represents a MarkerIdentifier
Tracker	Represents a Tacker (a.k.a. MarkerChain)

Statics

DIFFICULTY	The nonce value for adding complexity to the hash
DTC_HEADER	The standard header attribute for list (array) of the Data Usage Agreements