privacy-by-design

Privacy by Design

The seven foundational principles of Privacy by Design with practical implementation patterns for software engineering.

Knowledge Base

Origin and Context

Privacy by Design (PbD) was developed by Dr. Ann Cavoukian, former Information and Privacy Commissioner of Ontario, Canada. The framework was formally adopted as an international standard in 2010 by the International Assembly of Privacy Commissioners. GDPR Article 25 codified "data protection by design and by default" into law, making PbD a legal requirement for organizations processing EU residents' data.

PbD is not a checklist -- it is a design philosophy. The principles guide architectural decisions, feature design, and engineering practices throughout the system lifecycle.

The Seven Foundational Principles

Principle 1: Proactive not Reactive; Preventive not Remedial

Privacy measures must be designed in from the start, not added after privacy incidents occur.

Implementation patterns:

• Include privacy requirements in feature specifications alongside functional requirements
• Conduct privacy threat modeling (LINDDUN) during architecture design
• Perform DPIAs before building high-risk features, not after launch
• Include privacy criteria in definition-of-done for user stories

Anti-patterns:

• Building features first, then "adding privacy later"
• Conducting privacy reviews only when regulators ask
• Treating privacy incidents as the trigger for privacy improvements

Principle 2: Privacy as the Default Setting

Users should not need to take action to protect their privacy. The most privacy-protective settings must be the defaults.

Implementation patterns:

# Default to most restrictive sharing
class UserProfile:
    profile_visibility = "private"        # NOT "public"
    location_sharing = False              # NOT True
    activity_tracking = False             # NOT True
    third_party_data_sharing = False      # NOT True
    marketing_communications = False      # NOT True