# EVS-TAP & GCVWP System Architecture: Passenger Common Core Services (PCCS) Reuse

**Document Version**: 1.0.0  
**Author**: Agent 1 (Lead Architect & Agile Facilitator)  
**Security Classification**: SENSITIVE BUT UNCLASSIFIED / LAW ENFORCEMENT SENSITIVE  
**Governing Standard**: NIST SP 800-53 Rev 5 (Moderate-High Baseline), Zero Trust Architecture (NIST SP 800-207)

---

## 1. Architectural Philosophy: "Not a Snowflake"

A fundamental requirement of CBP modernization is avoiding isolated, bespoke silos that inflate Operations and Maintenance (O&M) lifecycle costs. The EVS-TAP (CNMI Economic Vitality & Security Travel Authorization Program) and GCVWP (Guam-CNMI Visa Waiver Program) systems are architected as modular microservices extending **CBP Passenger Common Core Services (PCCS)** and **Advanced Targeting System (ATS)** infrastructure.

```
+-------------------------------------------------------------------------------------------------------------+
|                                           1. PUBLIC INTAKE LAYER                                            |
|   - Multi-Lingual (EN, ZH-CN, ZH-TW, JA, KO)              - Section 508 / WCAG 2.1 AA Compliant             |
|   - Client-Side Passport OCR / MRZ Extraction             - Dynamic JSON Schema Form Engine                 |
|   - Standard GCVWP Flow                                   - Restricted Track Branch (EVS-TAP Parole)        |
+------------------------------------------------------|------------------------------------------------------+
                                                       | (Encrypted TLS 1.3 / mTLS)
+------------------------------------------------------v------------------------------------------------------+
|                                   2. ZERO TRUST API GATEWAY & SECURITY ENCLAVE                              |
|   - Attribute-Based Access Control (ABAC)                 - FIPS 140-3 Cryptographic Field Segmentation     |
+------------------------------------------------------|------------------------------------------------------+
                                                       |
+------------------------------------------------------v------------------------------------------------------+
|                                   3. CBP PASSENGER COMMON CORE SERVICES (PCCS)                              |
|  +--------------------------------+  +---------------------------------+  +-------------------------------+ |
|  | Event-Sourced Auth Datastore   |  | Officer Adjudication Portal     |  | Recurrent Vetting Engine      | |
|  | - Immutable state machine      |  | - Automated Rule Engine (<15m)  |  | - Event-driven TSDB/TECS sync | |
|  | - Shared agency read/write     |  | - Tiered TASPD/PSPD queues      |  | - Sub-second token revocation | |
|  +--------------------------------+  +---------------------------------+  +-------------------------------+ |
|  +--------------------------------+  +---------------------------------+  +-------------------------------+ |
|  | Carrier PDS Board/No-Board     |  | Lookouts / NCIC / Nlets         |  | Simplified Arrival (TVS)      | |
|  | - Sub-500ms SLA                |  | - Single-pane lookup adapter    |  | - Biometric match template    | |
|  | - Offline token graceful mode  |  | - Bi-directional sync           |  | - Guam/Saipan port validation | |
|  +--------------------------------+  +---------------------------------+  +-------------------------------+ |
+-------------------------------------------------------------------------------------------------------------+
```

---

## 2. Core Subsystems & Interfaces

### A. Public-Facing Intake Micro-Frontend
* **Multi-Lingual Engine**: Dynamic localization strings for English, Simplified Chinese, Traditional Chinese, Japanese, and Korean.
* **Section 508 / WCAG 2.1 AA Compliance**: High-contrast modes, ARIA live region screen-reader announcements, and pure keyboard tab navigation.
* **Client-Side Passport OCR**: Optical Character Recognition on ICAO 9303 standard Machine Readable Zones (MRZ) executed within browser memory; zero unencrypted biometric image storage.
* **Dynamic Form Schema**: Form structure governed by external JSON schemas, allowing 30-day regulatory question adjustments without recompilation.

### B. Common Core Travel Authorization Datastore
* **Event-Sourced Ledger**: Every state change (`SUBMITTED`, `AUTO_APPROVED`, `MANUAL_REVIEW`, `REVOKED_DEROGATORY`) is recorded as an immutable cryptographic event.
* **Bi-Directional Query Engine**: Sub-10ms lookup latency for Pre-Departure Screening (PDS) and Traveler Verification Service (TVS).

### C. Recurrent Vetting Stream Processor
* **Continuous Ingestion**: Kafka-based streaming pipeline ingesting delta feeds from Terrorist Screening Dataset (TSDB), TECS Lookout records, NCIC felony warrants, and INTERPOL Red Notices.
* **Sub-Second Token Revocation**: Invalidation events propagate to border primary and carrier systems in <850ms.

### D. Carrier PDS & Simplified Arrival Integration
* **Sub-500ms PDS SLA**: Responds with `BOARD` / `NO_BOARD` / `CONTACT_CARRIER_DESK` via secure interactive EDIFACT/JSON REST endpoints.
* **Graceful Degradation / Safe Offline Mode**: Carriers cache signed public verification keys to validate offline cryptographic tokens during internet outages.