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Certificate Transparency (CT)

A public logging system that records all SSL/TLS certificates, enabling detection of misissued or malicious certificates.

PKI & CertificatesAlso called: "ct logs", "certificate monitoring"

CT logs create an append-only, cryptographically verified record of every certificate issued.

Benefits for security

  • Detect rogue certificates issued for your domains.
  • Monitor for typosquatting and phishing attempts.
  • Verify CAs are following proper issuance procedures.
  • Meet browser requirements (Chrome, Safari require CT logging).

How to use CT logs

  • Monitor crt.sh or Censys for your domain names.
  • Set up alerts for new certificate issuance.
  • Validate certificates have SCTs (Signed Certificate Timestamps).