Secure File Transfer over QUIC (SFTPQ)

This project implements a minimal secure-FTP-style protocol (“SFTPQ”) on top of QUIC using Python and aioquic.
It provides a simple command-line client and server, with support for login, directory listing, file upload/download (with compression + SHA-256 integrity), and clean shutdown.

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Installation

1. Extract provided code

You should have received a zip archive named ftp.zip containing all source files. Unzip it and enter the ftp directory:

unzip ftp.zip
cd ftp

2. Create & activate a Python virtual environment

python3 -m venv venv
source venv/bin/activate        # on WSL

3. Install dependencies

pip install --upgrade pip
pip install aioquic
pip install -r requirements.txt

4. Generate TLS credentials

mkdir certs
cd certs

Generate a 2048-bit RSA private key:

openssl genrsa -out quic_private_key.pem 2048

Generate a self-signed certificate (valid 1 year):

openssl req -new -x509 \
-key quic_private_key.pem \
-out quic_certificate.pem \
-days 365 \
-subj "/C=US/ST=PA/L=Philadelphia/O=Drexel University/CN=localhost"

cd ..

5. Verify directory structure

After extraction and cert generation, you should have:

ftp/
├── certs/
│   ├── quic_certificate.pem
│   └── quic_private_key.pem
├── uploads/        ← created automatically by server
├── downloads/      ← created automatically by client
├── echo.py         ← main CLI entrypoint (client & server modes)
├── quic_engine.py  ← QUIC setup & protocol dispatch
├── echo_quic.py    ← QuicStreamEvent & EchoQuicConnection wrappers
├── echo_server.py  ← server-side protocol logic
├── echo_client.py  ← client-side protocol logic
├── pdu.py          ← message definitions (Datagram, MSG_TYPE_…)
├── requirements.txt
└── venv/

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Running the Server

In one terminal (with venv active), start the server:

python echo.py server \
  --cert-file certs/quic_certificate.pem \
  --key-file  certs/quic_private_key.pem \
  --listen    0.0.0.0 \
  --port      4433

Binds on all interfaces (0.0.0.0) port 4433 by default. Creates uploads/ if it does not exist.

or simply

python echo.py server

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Running the Client

In another terminal (with the same venv active), start the client:

python echo.py client \
  --server    localhost \
  --port      4433 \
  --cert-file certs/quic_certificate.pem

Prompts for Username and Password at first run (username- bob, password- builder). Creates downloads/ on first successful download.

or simply

python echo.py client

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Client Commands

At the sftpq> prompt, use:

1. list → request and display remote files stored by the server.

2. lls or list-local → show local files in your current directory.

3. upload → compress (gzip), hash (SHA-256), base64-encode, then send file.

4. download → request, receive, verify, decompress, and save file to downloads/.

5. exit → terminate session and close connection.

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Example Workflow

1. Start server (see above).
2. Connect client (see above).
3. Interact:

sftpq> list
Remote files: []

sftpq> upload example.txt
📤 Upload complete

sftpq> list
Remote files: ['example.txt']

sftpq> lls
Local files: ['example.txt', 'echo.py', ...]

sftpq> download example.txt
📥 Downloaded → downloads/example.txt

sftpq> exit
👋 Goodbye!

4. Confirm that uploads/example.txt on the server and downloads/example.txt on the client are identical.

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Notes & Troubleshooting

• uploads/ and downloads/ are auto-created; no manual setup needed.
• File transfers use GZIP compression + SHA-256 checksums for integrity.
• If you encounter “Bad gzip data” or “SHA256 mismatch,” ensure you’re using the same certificate on both sides and that no proxy is modifying packets.
• Change ports or file paths by supplying the corresponding flags (--port, --listen, --cert-file, --key-file) to echo.py.

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License

This project is licensed under the MIT License. See the LICENSE file for details.