Introduction to Privacy Engineering

Have you been part of that debate about whether a tomato is a fruit or a vegetable? I was surprised the first time someone explained that tomatoes are, botanically speaking, fruits. Yet, from my cooking and eating experience, tomatoes are vegetables. It seems that depending on the context, tomatoes can be either fruits or vegetables. 

Like tomatoes, we have a hard time pinning down what, exactly, “privacy engineering” means. Privacy engineering is a cross-cutting field that seeks to protect personal data through technical measures. Privacy engineering also may be involved with compliance and usability. Therefore, we could categorize it in several different ways. Privacy engineering can include software engineering, DevOps, data engineering, and policy and workflow design.

The title “Privacy Engineer” itself doesn’t give a lot of clarity. Some people have a “Privacy Engineer” title but are not strictly speaking “engineering” or building software. On the other hand, software engineers and research scientists are building privacy solutions, but don’t have the “Privacy Engineer” title. So why is privacy engineering so hard to define, and why is it important, anyway?

What privacy engineering isn't

It helps to narrow down the field a bit by saying what privacy engineering is NOT. 

• Privacy engineering is not a legal review of regulatory compliance. Yet, privacy engineering does need to be compliant. 
• Privacy engineering is not writing terms of use or a privacy policy, but it can help verify that a privacy policy is being followed. 
• Privacy engineering is not creating a marketing or ad campaign, but privacy engineering should build what users want. 
• Privacy engineering is not just implementing a slick mathematical algorithm in code – it’s also explaining why that algorithm matters. 

In short, privacy engineering is not an effort from one single team that can ignore other parts of a business or organization. Privacy is a team sport, and privacy engineering adds technical and engineering expertise to the team. Privacy engineering includes a technical or engineering component, and it requires communication with legal teams and an understanding of user experience. 

Why privacy engineering matters

There are three main reasons companies work so hard on privacy: regulation, market advantage, and customer trust. A full team of privacy experts, including privacy engineers, can help with all three of these goals. 

Privacy regulation is complex, with a seemingly ever-changing constellation of laws. Naturally, privacy lawyers need to understand the technology, but the technology is also constantly changing. Therefore, privacy engineers can complement the legal teams to maintain and build compliant systems through technical expertise. 

Privacy engineering can also help build a market advantage and maintain customer trust. Some companies go beyond legal compliance to build privacy features that customers love. Such companies can use privacy as a differentiator (as Apple has famously done [Leswing 2021]). 

On the other hand, companies can lose loyal customers if they don’t protect the data they have. Privacy engineering can work with security teams to build products that protect against attacks, breaches, or reckless use of data. This collaborative work helps maintain customer trust. 

Case studies — Building privacy into products

Privacy engineering is technical work that also involves understanding compliance and users’ expectations. Furthermore, privacy engineers not only help legal teams but can also help build a market advantage and maintain it through trust and loyalty. This may sound abstract, so let’s review some examples of privacy engineering work. 

Designing privacy-conscious applications

Privacy engineers can lead technical privacy reviews of consumer-facing apps or software. They may work with a software engineering team to write requirements for new features. Privacy engineers may coordinate with legal teams to make sure the user-facing text is both legally appropriate and accurately describes what is going on in the backend. In this example, privacy engineering can involve architecture and design decisions, but will not necessarily write the code. 

Assessing privacy risk

Testing and measurement help companies understand their overall risk. When it comes to privacy, it’s important to use the appropriate metrics and tests [Kissner 2023]. This is where privacy engineering can help formulate relevant metrics, test systems for vulnerabilities, and prioritize what needs to be fixed. For example, the US Census Bureau has brought in expert data analysts to test whether the shared census data can be re-identified [Macagnone 2020].  

Building privacy into the software 

Privacy engineering can involve building privacy controls and features into the software. For example, encrypting data can be complex and needs to be done carefully. (Proton builds encrypted email solutions and has written about this engineering challenge [Butler 2021].) Privacy engineering also includes implementing the controls required by regulation. Automating Data Subject Access Requests or periodically deleting data are examples of privacy engineering tasks.  

What it takes to be a good privacy engineer 

If this sounds compelling, you may wonder what it takes to be a privacy engineer, or perhaps what to look for when hiring a privacy engineer. 

Privacy engineers should be technical but can come from all sorts of backgrounds. The case studies above could also be done by program managers, data analysts, or software engineers. I know of lawyers and journalists who have become privacy engineers because they found the technical aspects interesting.

Privacy is a team effort, so privacy engineers should enjoy working with multiple, different teams. Privacy engineers need to context switch and talk to their audience. For example, security and legal teams may be motivated by different language or explanations. Privacy engineers should identify and work with all stakeholders, from marketing to developers.

Privacy engineers should have empathy for all types of people. Privacy is about protecting people, so privacy engineers should be able to envision how different people feel when their data is collected, stored, used, and shared. Privacy engineers can work with designers to build explanations and settings that a wide variety of people understand and want. 

Technology and regulations are continuously being updated, so privacy engineers need to be adaptable and ready for change. Continuous learning is crucial (and I have some resources below). It can be difficult to stay current on every single topic related to privacy, but privacy engineers should understand fundamental concepts and how they can be applied in different contexts. 

Catching up with the tomato analogy

I hope you like tomatoes because I’m about to overuse the analogy. Like tomatoes, privacy engineering can fall into different categories and still be incredibly useful and relevant. Privacy engineering can create that special sauce that allows companies to comply with regulations, gain market advantage, and maintain customer trust.  Privacy engineers play a crucial role in protecting data, as they should bring the different flavors of the organization together. 

Additional Resources

There are tons of resources to learn more about privacy engineering. 

1. See Debra Farber's top 20 privacy engineering resources
2. Join Privado’s Privacy Engineering Community to meet privacy engineers of all levels of experience
3. Privado and Nishant Bhajaria’s free Technical Privacy Masterclass: 26 lessons and over 2 hours of content.
4. Also check out my newsletter and RadarFirst’s top privacy podcasts of 2023
5. Carnegie Mellon University and the Technische Universität Berlin are two universities that offer research and further studies in Privacy Engineering.

References: 

1. [Leswing 2021] Leswing, Kif  Apple is turning privacy into a business advantage, not just a marketing slogan, CNBC.com, June 7 2021 https://www.cnbc.com/2021/06/07/apple-is-turning-privacy-into-a-business-advantage.html
2. [Kissner 2023] Kissner, Lea Presentation at 2023 USENIX Conference on Privacy Engineering Practice and Respect  PEPR '23 - Bad Metrics and Very Bad Decisions 
3. [Macagnone 2020] Macagnone, Michele   Census Privacy Protection Changes Need Testing, Experts Say, GovTech.com June 11, 2020 https://www.govtech.com/security/us-census-bureau-ready-to-test-privacy-tools.html
4. [Butler 2021]  Butler, Bart 2021 in review: An update from the Proton Engineering team, Proton.me August 25 2022 https://proton.me/blog/engineering-team-2021-update