Certificate Authority

Noun · Security & Infosec

Definitions

  1. A trusted entity that issues digital certificates, verifying that the holder of a certificate is who they claim to be. The trust anchors of HTTPS — when a CA is compromised, the entire chain of trust breaks.

    In plain English: An organization trusted to verify that websites are who they claim to be — the digital equivalent of a notary public for the internet.

  2. Let's Encrypt (launched 2015) democratized HTTPS by providing free, automated certificates, making CAs accessible to everyone. Before it, the cost and complexity of certificates meant most small websites ran unencrypted HTTP.

    Example: 'Let's Encrypt issues over 3 million certificates per day. They single-handedly made HTTPS the default for the web.'

    Source: Let's Encrypt impact

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