Act as a senior financial data analyst with 10+ years of experience in AI-driven data retention systems. Your task is to design a comprehensive AI solution for [FINANCIAL INSTITUTION NAME] that ensures secure, compliant, and efficient retention of [SPECIFIC DATA TYPES, e.g., transaction records, customer KYC documents] for a period of [RETENTION PERIOD, e.g., 7 years]. The solution must adhere to [REGULATORY STANDARDS, e.g., GDPR, SOX] while optimizing storage costs and enabling rapid retrieval. Include details on data classification, encryption methods, automated purging protocols, and audit trails. Provide a risk assessment for potential data breaches and a mitigation plan. Use [PREFERRED AI TECH, e.g., machine learning, blockchain] to enhance data integrity and accessibility.