android-encrypted-archiver/.planning/STATE.md

Project State

Project Reference

See: .planning/PROJECT.md (updated 2026-02-24)

Core value: Archive impossible to unpack without knowing the format -- standard tools (7z, tar, unzip, binwalk) cannot recognize or extract contents Current focus: Phase 3: Round-Trip Verification

Current Position

Phase: 3 of 6 (Round-Trip Verification) Plan: 1 of 2 in current phase Status: Plan 03-01 complete, ready for Plan 03-02 Last activity: 2026-02-24 -- Library crate + 19 unit tests for crypto/compression/format

Progress: [████░░░░░░] 43%

Performance Metrics

Velocity:

• Total plans completed: 4
• Average duration: 4 min
• Total execution time: 0.3 hours

By Phase:

Phase	Plans	Total	Avg/Plan
1. Format Specification	1	7 min	7 min
2. Core Archiver	2/2	6 min	3 min
3. Round-Trip Verification	1/2	3 min	3 min

Recent Trend:

• Last 5 plans: 7min, 4min, 2min, 3min
• Trend: stable/improving

Updated after each plan completion

Accumulated Context

Decisions

Decisions are logged in PROJECT.md Key Decisions table. Recent decisions affecting current work:

• Roadmap: Format spec must precede all implementation (all three decoders build against same spec)
• Roadmap: Obfuscation (XOR headers, encrypted TOC, decoy padding) deferred to Phase 6 after all decoders work without it
• Phase 1: IV stored only in TOC, not duplicated in data blocks (simplifies shell dd extraction)
• Phase 1: Same 32-byte key for AES-256-CBC and HMAC-SHA-256 in v1 (v2 will use HKDF)
• Phase 1: Magic bytes 0x00 0xEA 0x72 0x63 (leading null signals binary)
• Phase 1: HMAC scope = IV (16 bytes) || ciphertext (encrypted_size bytes)
• Phase 2: Used rand::Fill::fill() for IV generation (correct rand 0.9 API)
• Phase 2: Manual binary serialization with to_le_bytes/from_le_bytes (no serde/bincode)
• Phase 2: Filename-only entry names (not full paths) for archive portability
• Phase 2: HMAC failure skips file and continues; SHA-256 mismatch warns but writes
• Phase 2: Flags bit 0 set only when at least one file is actually compressed
• Phase 3: Library crate with pub mod re-exports for all 6 modules
• Phase 3: Unit tests embedded in modules via #[cfg(test)] (not separate files)
• Phase 3: hex-literal v1.1 for compile-time SHA-256 known-value assertions

Pending Todos

None yet.

Blockers/Concerns

• Open question: Does target busybox have openssl enc -aes-256-cbc with -K/-iv flags? (affects Phase 5)
• Open question: Is xxd available in target busybox? Fallback: od (affects Phase 5; spec includes od fallback functions)
• RESOLVED: HMAC uses same key as AES in v1 (decided in Phase 1 spec, v2 will use HKDF)

Session Continuity

Last session: 2026-02-24 Stopped at: Completed 03-01-PLAN.md (Library crate + unit tests) Resume file: None