PackerX

A lightweight C++ utility to compress and decompress files using zlib. Preserves original file extension in the binary-payload, adds integrity check via CRC32, and anonymizes stored/compressed data using salted SHA-256 hashing.

Directory Structure

PackerX/
├── compressor.cpp              # Compression logic
├── decompressor.cpp            # Decompression + CRC verifier
├── compressed_output/          # Compressed .bin files (hashed names)
├── decompressed_output/        # Recovered files
├── input_files/                # Original raw files
└── README.md                   # This documentation

Build Instructions

Ensure you have a C++17-compatible compiler. zlib and OpenSSL installed (libssl-dev on Ubuntu / brew install openssl on macOS)

Compile Commands

1. Clone the repository.
2. Compile the program using your C++ compiler, linking against the zlib library.

g++ -std=c++17 -o packerx compressor.cpp -lz -lssl -lcrypto
g++ -std=c++17 -o unpackerx decompressor.cpp -lz -lssl -lcrypto

3. Run the compiled program with the file name you want to compress or decompress using command line.

./packerx input_files/example.txt
./unpackerx input_files/example.txt

4. Compressed file would be saved in folder compressed_output, while decompressed file would be saved in folder decompresssed_output.

Compression Output: Example

Compression complete.
Output: compressed_output/f5889fad896cf23c5cc4a9091c9deccd17e39b3ee1fac4cf91b92042328b6cf4.bin
SHA-256 (salted): f5889fad896cf23c5cc4a9091c9deccd17e39b3ee1fac4cf91b92042328b6cf4
Extension embedded: .pdf
CRC32: 0x3E645559
Original size: 4285949 bytes
Compressed size (+meta): 3793879 bytes

Decompression Output: Example

If file is untampered: Result format in terminal.

Debug --> Actual CRC32: 1046762841, Extracted CRC32: 1046762841
Decompression successful!
Restored file: decompressed_output/Strategy_Insights_References_restored.pdf
Extension: .pdf
Size: 4285949 bytes

If file is corrupted/tampered: Result format in terminal.

CRC32 check FAILED. File may be corrupted.

Features

• Deterministic File Hashing
  Uses salted SHA-256 64 hex character hash of original filename for consistent and reversible file identification.

• Extension-Preserving Compression
  Stores file extension metadata in compressed output, allowing accurate restoration of the original format.

• CRC32 Checksum Validation
  Adds a CRC32 checksum for integrity verification during decompression to detect tampered or corrupted files.

• Organized Directory Output
  Compressed files saved in compressed_output/, decompressed files restored to decompressed_output/.

• Robust Compression Logic
  Uses zlib for efficient compression; handles empty files, memory errors, and corrupted inputs gracefully.

Future Work

• Create an NPM package for easy integration in web apps.
• Automatically upload compressed files to cloud storage.
• Enable file recovery using a unique hashed ID.
• Support batch compression of multiple files.
• Add password protection for secure file access.