audittrail

An audit trail, or audit trail log, is a chronological record of system activities and events that documents what occurred within a computer system, application, or data store. Its primary purpose is to provide evidence of actions taken and to support accountability, traceability, and forensic analysis.

An audit trail typically includes timestamps, user or process identifiers, the type of action (such as create, read, update, delete), the affected resource, and contextual details such as IP address, location, device, and the before-and-after values for data changes. In data management, it can also record changes to metadata, configurations, and access controls.

Audit trails come in several forms, including application logs, database transaction logs, access logs, and change logs. They may be maintained at the system level, by middleware, or by data governance platforms, and may be stored centrally or distributed across services.

To ensure integrity and admissibility, audit trails are often made tamper-evident through mechanisms such as cryptographic hashes, digital signatures, write-once-read-many storage, and secure, access-controlled storage. Time synchronization and standardized formats facilitate cross-system correlation and retrieval.

Auditing requirements are defined by frameworks and regulations such as ISO 27001, NIST SP 800-92, PCI DSS, HIPAA, and SOX. Effective audit trails support regulatory compliance, fraud detection, incident response, and post-incident investigations, as well as data lineage and change-management processes.

Common challenges include handling large volumes of logs, protecting privacy, maintaining retention policies, ensuring log integrity, and minimizing performance impact. Best practices emphasize principled data minimization, centralized log management, secure archival, and regular review and alerting.

Related concepts include audit logs, data lineage, change management, and security information and event management (SIEM) systems.