Also known as: CA · TLS certificate · PKI
A certificate authority (CA) is a trusted organisation that issues digital certificates binding a cryptographic public key to a verified identity, such as a domain name, enabling encrypted and authenticated connections.
The web's trust model is a hierarchy: browsers ship with a set of trusted root certificates, and any CA in that set can issue a certificate for any domain. This makes the system only as trustworthy as its least competent member, which is why CA misissuance incidents are treated so seriously.
Certificate Transparency logs mitigate this by requiring certificates to be publicly recorded, so domain owners can detect unauthorised issuance for their domains rather than relying on CAs never making mistakes.
End-to-End Encryption
End-to-end encryption (E2EE) is a system in which messages are encrypted on the sender's device and decrypted only on the recipient's, so that no intermediary — including the service provider — can read the content in transit or at rest on its servers.
Code Signing
Code signing is the practice of cryptographically signing software artifacts so that recipients can verify who produced them and confirm the code has not been altered since signing.
TLS
TLS (Transport Layer Security) is the cryptographic protocol that encrypts data in transit between clients and servers, providing confidentiality, integrity, and server authentication — most visibly as the S in HTTPS.
Zero Trust
Zero trust is a security architecture that removes implicit trust based on network location, requiring every request to be authenticated, authorised, and continuously validated regardless of whether it originates inside or outside the corporate network.