When users visit secure websites or send encrypted data over the internet, they rely on digital certificates and Public Key Infrastructure (PKI). In IB Computer Science, students are expected to understand what digital certificates are, why they are needed, and how PKI supports trust and secure communication.
IB examiners focus on trust, verification, and authenticity, not technical implementation details.
Why Trust Is a Problem on the Internet
The internet is an open network where:
- Anyone can claim to be someone else
- Data can be intercepted
- Fake websites can imitate real ones
Before encryption can be trusted, users must know:
- Who they are communicating with
Digital certificates and PKI exist to solve this trust problem.
What Is a Digital Certificate?
A digital certificate is an electronic document that:
- Confirms the identity of an entity
- Links that identity to a public key
A digital certificate typically contains:
- The owner’s identity (e.g. a website)
- The owner’s public key
- A digital signature from a trusted authority
In IB terms, a digital certificate proves authenticity.
What Is a Certificate Authority (CA)?
A Certificate Authority (CA) is a trusted organisation that:
- Issues digital certificates
