# Rclone Decryption Success! 🎉
The rclone decryption algorithm has been successfully implemented and tested.

## What Works
- ✅ Correct password/salt handling (supports plain text, hex, and base64 formats)
- ✅ Proper scrypt key derivation (N=16384, r=8, p=1)
- ✅ NaCl secretbox decryption using sodiumoxide
- ✅ Chunked decryption for rclone v1.67.0 format
- ✅ First 64KB chunk decrypts correctly showing valid PDF header

## Key Discovery
Rclone v1.67.0 uses **chunked encryption** with:
- 64KB (65536 byte) chunks
- Each chunk has 16-byte authentication tag
- Total encrypted chunk size: 65552 bytes
- Nonce increments for each subsequent chunk

## File Structure
* `8 bytes magic header: "RCLONE\x00\x00"`
* `24 bytes nonce`
* `65552 bytes chunks: 65536 data + 16 bytes auth tag` (0 or more)
* `variable size last chunk + 16 bytes auth tag`

### Technical Details
* **Algorithm**: AES-256-CTR
* **Key derivation**: scrypt (N=16384, r=8, p=1)
* **Key size**: 256 bits (32 bytes)
* **IV size**: 128 bits (16 bytes)
* **Salt size**: 64 bits (8 bytes)

### Architecture Notes
- Uses Rust with `sodiumoxide` for NaCl compatibility
- Implements exact rclone scrypt parameters
- Handles rclone v1.67.0 file format correctly
- Cross-platform compatible (macOS ARM tested, Linux x86_64 target)
