Certificate Transparency Log Entries

Understanding CT Log Entries

Certificate Transparency Log Entries represent the specific records and metadata associated with a certificate’s inclusion in public Certificate Transparency logs. These entries provide detailed information about when, where, and how a certificate was logged, creating an immutable audit trail that enhances the security and transparency of the PKI ecosystem.

Entry Structure and Information

Each CT log entry contains comprehensive information about the certificate logging event:

• Log Name: Which CT log server recorded the certificate
• Entry Index: Unique identifier within that specific log
• Timestamp: Exact time when the certificate was logged
• Signature: Cryptographic proof from the log server
• Certificate Data: The actual certificate that was logged

Monitoring and Security Applications

CT log entries enable various security monitoring and compliance activities. Organizations can subscribe to CT log feeds to receive real-time notifications when certificates are issued for their domains, helping detect unauthorized certificate issuance. Security researchers use CT log data to identify patterns in certificate misuse and track the activities of malicious actors. The entries also support automated certificate discovery tools that help organizations maintain inventories of their SSL certificates across complex infrastructures. Multiple log entries for the same certificate across different CT logs provide redundancy and increase the reliability of the transparency system.