Training Trains Internship
Student login
← Cryptography learning path
Cryptography · Module 7 of 10

Certificates and PKI

Trust public keys through certificates.

📖 Key ideas

  1. A digital certificate binds a public key to an identity.
  2. Certificate Authorities (CAs) issue and sign certificates.
  3. Browsers trust root CAs; chains link certificates to roots.
  4. X.509 is the certificate format.
  5. Certificates expire and can be revoked.
💡 Real-life example: A certificate is an Aadhaar card for a website: issued by a trusted authority, proving identity.
CertificateBinds a public key to an identity
CACertificate Authority
PKIPublic Key Infrastructure
X.509Standard certificate format