chromapress 1.0.1

Compress hard, encrypt harder — LZMA2 + AES-256-GCM + Scrypt

ChromaPress

Compress hard, encrypt harder.

A high-performance file compression and encryption tool combining LZMA2 extreme compression, SHA-256 chunk deduplication, and AES-256-GCM authenticated encryption with a memory-hard Scrypt KDF.

Installation

pip install chromapress

Quick Start

# Compress + encrypt a file
press myfile.dat

# Decompress
press myfile.dat.press

# Compress without encryption
press myfile.dat --no-encrypt

# Interactive mode
press

# File info (no password needed)
press info myfile.dat.press

Features

• LZMA2 Extreme — Preset 9 extreme, the strongest lossless compression available
• AES-256-GCM — Authenticated encryption with tamper detection
• Scrypt KDF — Memory-hard key derivation (up to 1 GB RAM per brute-force attempt)
• SHA-256 Deduplication — Chunk-level dedup eliminates identical blocks before compression
• Interactive Mode — Arrow-key guided menu when run with no arguments
• Windows Integration — Explorer right-click context menu support

Compression Pipeline

INPUT → CHUNK (64KB) → DEDUP (SHA-256) → LZMA2 (preset 9) → AES-256-GCM → .press

CLI Options

Flag	Description
<file>	Compress (or auto-decompress if .press)
-d <file>	Force decompress mode
-o <path>	Output path
-s <level>	Security: standard, high, extreme
-c <bytes>	Chunk size (default: 65536)
--no-encrypt	Compress only, no encryption
-f	Force overwrite
-q	Quiet mode
-v	Show version
info <file>	Inspect .press file metadata

Security Levels

Level	Scrypt N	RAM per attempt
Standard	2^14	16 MB
High	2^17	128 MB
Extreme	2^20	1 GB

Benchmarks

50 MB test files, Python 3.10, Windows 11. No encryption (compression only).

File Type	gzip -9	bzip2 -9	lzma -9e	ChromaPress
Server Logs	18.0x	36.7x	1434.7x	1414.6x
CSV Data	9.5x	13.4x	31.2x	23.8x
JSON Data	10.2x	21.4x	60.9x	60.5x
Binary/DB	11.9x	10.5x	15.5x	16.3x
Random	1.0x	1.0x	1.0x	1.0x

ChromaPress wins on binary/structured data thanks to SHA-256 dedup + LZMA2 extreme. On text, it matches lzma-9e. On random data, all tools hit the information theory limit.

Full benchmark: see BENCHMARK.md | Run: python benchmark.py

Requirements

• Python 3.10+
• cryptography >= 41.0

License

MIT