• SECURITY_OVERVIEW.md — Public-facing security summary. Cryptographic standards, known limitations, threat model overview.
• security-model.md — Developer/auditor reference. Full 8-layer architecture, key hierarchy, threat model tables, new endpoint checklist.
• pbkdf2-iterations-upgrade.md — PBKDF2 parameters, iteration counts, hardware constraints, compatibility notes for decrypt_export.html.

• ENDPOINTS.md — Complete API reference. All endpoints with auth requirements, request/response formats, security notation.
• system_design.md — Internal architecture. Boot sequence, PIN design, shutdown/deep sleep, data persistence table, error handling.
• LOGGING_SYSTEM.md — Log levels, LOG_* macros, Serial output format, filtering.
• url-obfuscation.md — URL obfuscation layer internals, epoch rotation, endpoint registration checklist.
• multi-board.md — Multi-board development rules. Three types of platform differences, scaling checklist, golden rule.
• PORTING.md — Hardware porting guide. Step-by-step instructions for adapting SecureGen firmware to new ESP32/S3 boards. Covers hardware requirements, board header creation, platformio.ini configuration, capability flags (USB HID, PSRAM), deep sleep wake pins, display geometry, security checklist, and common mistakes to avoid.
• abandoned-ideas.md — Rejected features and architectural decisions. Documents approaches that were considered but abandoned, with reasoning and alternatives.

Hardware reference for supported targets. Each file covers: MCU, display, pinout, USB/flashing specifics, known quirks.

• t-display.md — LilyGo T-Display ESP32 (1.14", Classic ESP32, SPI display, CH340 USB).
• t-display-s3.md — LilyGo T-Display-S3 (1.9", ESP32-S3, 8-bit parallel display, native USB, USB HID capable).

• GUIDE.html — Device operation manual.
• GUIDE.ru.html — Device operation manual (Russian).
• MODES.md — Network and display modes, feature matrix, mode selection at startup.
• decrypt-export-guide.md — Offline export decryption tool guide.
• rtc_mastering.md — DS3231 RTC module connection guide. Wiring diagrams, pin assignments (ESP32/S3), enabling RTC in firmware, troubleshooting.

Board-specific constants → include/boards/
Build flags → platformio.ini
Feature guards → #ifdef BOARD_HAS_USB_HID

Last updated: April 2026