android-encrypted-archiver/.planning/phases/02-core-archiver/02-02-SUMMARY.md

phase, plan, subsystem, tags, requires, provides, affects, tech-stack, key-files, key-decisions, patterns-established, requirements-completed, duration, completed

phase	plan	subsystem	tags	requires	provides	affects	tech-stack	key-files	key-decisions	patterns-established	requirements-completed	duration	completed
02-core-archiver	02	archive, cli	aes-256-cbc hmac-sha256 gzip binary-format pack unpack inspect encrypt-then-mac	phase plan provides 02-core-archiver 01 Crypto pipeline (encrypt/decrypt/HMAC/SHA-256), format types (Header/TocEntry serialization), compression (gzip/heuristic), CLI skeleton, hardcoded key	pack() function: two-pass archive writer producing FORMAT.md-compliant archives unpack() function: HMAC-first verification, AES-256-CBC decryption, optional gzip decompression, SHA-256 integrity check inspect() function: metadata display (sizes, offsets, IVs, HMACs, SHA-256) without decryption CLI dispatch wiring all three commands to archive module Directory traversal protection in unpack	03-round-trip-verification 04-kotlin-decoder 05-shell-decoder 06-obfuscation	added patterns two-pass archive writing (process then compute offsets) HMAC-before-decrypt verification order filename-only entry names from full paths	created modified src/archive.rs src/main.rs	Use filename-only (not full path) as archive entry name to keep entries portable Directory traversal protection: reject names starting with / or containing .. HMAC failure skips file and continues; SHA-256 mismatch warns but still writes file Flags byte bit 0 set only when at least one file is actually compressed	Two-pass archive writing: Pass 1 processes files in memory, Pass 2 computes offsets and writes sequentially HMAC verified before decryption attempt (encrypt-then-MAC per FORMAT.md Section 10) Per-file error handling: HMAC/SHA-256 failures increment error count, non-zero exit on any errors Inline TOC size computation: sum of (101 + name.len()) per file	CLI-02 CLI-03	2min	2026-02-24

Phase 2 Plan 2: Archive Commands Summary

Pack/unpack/inspect commands with AES-256-CBC encryption, HMAC-SHA-256 verification, gzip compression, and FORMAT.md-compliant binary output

Performance

• Duration: 2 min
• Started: 2026-02-24T21:01:22Z
• Completed: 2026-02-24T21:03:40Z
• Tasks: 1
• Files modified: 2

Accomplishments

• Fully functional encrypted_archive binary with pack, unpack, and inspect commands
• Round-trip verified: packed files are byte-identical after unpacking (text + binary)
• HMAC tamper detection verified: flipping a ciphertext byte triggers rejection with non-zero exit
• Compression auto-detection verified: .apk files stored without gzip (compression_flag=0, flags=0x00)
• Archive starts with magic bytes 0x00 0xEA 0x72 0x63 (not recognized as any standard format)

Task Commits

Each task was committed atomically:

1. Task 1: Implement pack, inspect, unpack commands and wire CLI - be50707 (feat)

Files Created/Modified

• src/archive.rs - Pack, unpack, and inspect orchestration (237 lines): two-pass pack writer, HMAC-first unpack, metadata inspect
• src/main.rs - CLI dispatch wiring Commands enum to archive::pack/unpack/inspect

Decisions Made

• Filename-only entries: Archive stores only the filename (not the full path) for portability across systems
• Directory traversal protection: Reject filenames starting with / or containing .. during unpack (Rule 2 - security)
• Error continuation: HMAC failure skips the file; SHA-256 mismatch warns but still writes (per FORMAT.md Section 10 guidance)
• Flags byte logic: Header flags bit 0 is set only when at least one file in the archive has compression_flag=1

Deviations from Plan

None - plan executed exactly as written.

Issues Encountered

None.

User Setup Required

None - no external service configuration required.

Next Phase Readiness

• Phase 2 (Core Archiver) is complete: all modules wired and functional
• Ready for Phase 3 (Round-trip verification / integration tests)
• Two dead-code warnings remain for format::entry_size and format::compute_toc_size helper functions (usable by future code)
• All obfuscation features deferred to Phase 6 as per ROADMAP

Self-Check: PASSED

All 2 modified files verified present. Task commit (be50707) verified in git log.

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Phase: 02-core-archiver Completed: 2026-02-24