Certificates - 1.4

Overview of Certificates

A digital certificate is an electronic document that contains a public key, identification information about the entity it belongs to, and a digital signature from a trusted Certificate Authority (CA).

Certificates provide the "trust" in digital communications by ensuring the authenticity and integrity of the entities involved. They verify the identity of the entity by binding the public key to a verified individual or organization, preventing impersonation attacks.

The "root of trust" refers to a trusted entity, such as a Certificate Authority (CA), that issues and signs certificates to validate their authenticity. This ensures that participants can trust the certificates used in secure communications. Hardware Security Modules (HSMs) are often used to securely manage and store cryptographic keys used in certificate issuance.

Certificates can be revoked if they are compromised, no longer valid, or no longer needed. The Online Certificate Status Protocol (OCSP) is commonly used to check the revocation status of a certificate in real-time, ensuring its validity.

To obtain a certificate, an entity must submit a Certificate Signing Request (CSR) to a CA. The CA will validate the request and, if legitimate, issue the certificate, which can then be used for secure communications.

Follow-up Questions

What is a digital signature? Is it just a unique hashed ID string?

A digital signature is more than just a unique hashed ID string. It is a cryptographic signature created using the sender's private key, providing assurance that the message was sent by the legitimate sender and has not been altered during transit. The recipient uses the sender's public key to verify the digital signature, thus ensuring both authenticity and integrity of the message.