HIPAA-Compliant Patient Data Anonymization Pipeline

Design a PostgreSQL solution that automatically anonymizes patient medical records while preserving statistical integrity. Create a stored procedure that: 1) Masks personally identifiable information (PII) using one-way hash functions, 2) Generates anonymized unique identifiers, 3) Implements reversible encryption for authorized medical research, and 4) Logs all anonymization actions with detailed audit trails. Include robust error handling and performance optimization for datasets exceeding 1 million patient records.