📝 Audit Logging

Compliance under Saudi regulations (ZATCA, GOSI, PDPL, and NCA) requires an immutable, tamper-evident record of all user, system, and AI operations. BayanCore implements a zero-deletion audit trail architecture.

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1. Immutable Log Architecture

To prevent unauthorized manipulation of historical logs, the auditing system isolates writes:

• Database Constraints: The audit log table resides in a dedicated MariaDB schema. The application service connects to this schema using a user role restricted solely to INSERT privileges. No UPDATE or DELETE executions are accepted.
• Cryptographic Hash Chaining: Every log entry contains the SHA-256 signature of the preceding row's metadata and payload. This links all records in a chronological cryptographic chain: Row Hash = SHA256(Current Payload + Previous Row Hash)
• Tamper Detection: A daily system cron job recalculates the hashes across all rows. If a hash mismatch is detected (indicating manual database alteration), the system locks and flags an alert to the Security Ops Dashboard.

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2. "Action by User via AI" Log Format

When actions are executed or drafted by the AI assistant (Tiers 2 and 3), the system logs the interaction using a standardized JSON schema to preserve human responsibility and clear audit paths.

Sample Audit Payload

{
  "log_id": "audit_8271b-29a3",
  "actor": {
    "user_id": "usr_9281a",
    "role": "Finance Manager",
    "ip_address": "197.34.120.4"
  },
  "action": {
    "type": "POST_PURCHASE_INVOICE",
    "timestamp_gregorian": "2026-06-02T01:15:00Z",
    "timestamp_hijri": "1447-12-16T01:15:00Z",
    "entity_type": "Purchase Invoice",
    "entity_id": "PINV-2026-0041"
  },
  "agency": {
    "generated_by_ai": true,
    "ai_agent_id": "agent_ap_ocr_v1",
    "ai_confidence_score": 0.98,
    "user_review_action": "APPROVED_WITHOUT_EDIT",
    "prompt_interaction_id": "prompt_8812c"
  },
  "changes": {
    "before": null,
    "after": {
      "vendor_id": "vendor_921a",
      "gross_amount": 15000.00,
      "vat_amount": 2250.00
    }
  },
  "hash": "d5f8a0e882a1768c92ff3b99..."
}

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3. Data Retention Schedule

To align with ZATCA and Saudi Commercial Laws, data is archived and purged based on a structured lifecycle:

Data Type	Statutory Retention	Storage Tier	Immutability Control
Financial Transactions / GL	10 Years	relational MariaDB	Append-Only, Write-Once
ZATCA Signed Invoice XMLs	10 Years	OCI Object Store (WORM)	Cryptographic Hash Chain
User Activity Logs	5 Years	Partitioned Audit Tables	SHA-256 Hash Chain
System Operations Logs	2 Years	OCI Object Store	Auto-Purged after 2 Years
AI Context Tokens / Cache	30 Days	Redis / Temp DB	Auto-Purged after 30 Days