Secure File Split/Join Tool - Enterprise Edition v5.5

FIXES IN v5.5:
- ✅ Fixed Ed25519 import (compatible with all PyCryptodome versions)
- ✅ Correct GF(256) implementation using log/antilog tables
- ✅ Share authentication key derived from master_key (not stored publicly)
- ✅ Shares bound to archive_id (prevents cross-archive mixing)
- ✅ Fixed compression flush accounting
- ✅ Shard magic/version validation
- ✅ Single signing identity (removed redundant root key)
- ✅ Password verifier for immediate feedback
- ✅ Nonce counter design for deterministic uniqueness
- ✅ CLI password prompt (no command-line exposure)

REQUIREMENTS:
- Python 3.6+
- pycryptodome
- argon2-cffi
- colorama
- tqdm
- zfec
- zstandard
- blake3
- filelock
- psutil

INSTALLATION:
    sudo apt install python3-pip
    pip3 install pycryptodome argon2-cffi colorama tqdm zfec zstandard blake3 filelock psutil

For more information, see the examples:
    fsplit --examples
