📧 amelis-smime-decrypt

A Python library and CLI tool that connects to an IMAP email mailbox, fetches S/MIME encrypted emails, decrypts them using a P12/PFX certificate, and extracts PDF attachments with intelligent deduplication and flexible post-processing.

🚀 Features

✔️ IMAP Integration - Connect to any IMAP email server
✔️ S/MIME Decryption - Decrypt emails using P12/PFX certificates (RSA-OAEP support)
✔️ Subject Filtering - Fetch emails matching specific keywords
✔️ Deduplication - Automatically handle duplicate emails (same subject)
✔️ Flexible Actions - Mark as seen, delete, or move emails after processing
✔️ CLI + Library - Use as standalone tool or import as Python library
✔️ PDF Data Extraction - Extract patient data from PDFs and rename files with flexible patterns

📦 Installation

For Users

pip install amelis-smime-decrypt

For Development

Prerequisites (Linux/Debian)

sudo apt-get install libssl-dev swig python3-dev gcc python3-virtualenv

Clone and Setup

git clone https://github.com/nerdocs/amelis-smime-decrypt.git
cd amelis-smime-decrypt

# Using uv (recommended)
uv venv
. .venv/bin/activate  # or: source .venv/bin/activate
uv sync

# Or using pip
pip install -e ".[dev]"

🔑 Configuration

Using .env File

Create an .env file from the template:

cp .env.example .env

Edit the configuration:

# IMAP Configuration
IMAP_SERVER=imap.example.com
IMAP_PORT=993
EMAIL_ACCOUNT=info@example.com
EMAIL_PASSWORD=supersecretpassword

# S/MIME Certificate (P12/PFX format)
P12_CERTIFICATE_PATH=./certificate.p12
PFX_PASSWORD=your_certificate_password

# Output Configuration
SAVE_DIRECTORY=./output
SUBJECT_KEYWORD="Auftrag"

# Email Post-Processing
EMAIL_ACTION=mark_seen           # Options: mark_seen | delete | move:FolderName
DUPLICATE_ACTION=mark_seen       # Action for older duplicate emails

# PDF Renaming Pattern (optional)
# Available variables: {last_name}, {first_name}, {birth_date}, {barcode_number},
#                      {samplecollectiondate}, {receiptdate}, {finalreport}, etc.
RENAME_PATTERN="{last_name}_{first_name}_{birth_date}_{barcode_number}.pdf"

Using CLI Arguments (Override .env)

All settings can be overridden via command-line arguments:

amelis-smime-decrypt \
  --imap-server imap.example.com \
  --imap-port 993 \
  --imap-user user@example.com \
  --imap-pass secret \
  --cert certificate.p12 \
  --password pfx_pass \
  --subject "Order" \
  --output ./orders \
  --email-action delete \
  --duplicate-action "move:Archive"

🛠️ Usage

Basic Usage

Run with default configuration from .env:

amelis-smime-decrypt

With Custom Arguments

amelis-smime-decrypt --subject "Auftrag" --output ./output_directory

Get Help

amelis-smime-decrypt --help

How It Works

1. Connects to IMAP server with provided credentials
2. Fetches emails matching the subject keyword
3. Deduplicates emails with same subject (keeps latest)
4. Decrypts S/MIME encrypted messages
5. Extracts PDF attachments
6. Renames PDFs based on extracted data (if pattern configured)
7. Performs configured action (mark seen/delete/move)

📂 Output

Extracted PDFs are saved to SAVE_DIRECTORY (default: ./output/):

output/
 ├── Mueller_Hans_01.01.1980_BC123456.pdf
 ├── Schmidt_Anna_15.05.1975_BC789012.pdf

Security Considerations

• Protect your certificate: Keep P12/PFX files secure, never commit to version control
• Use environment variables: Store credentials in .env (add to .gitignore)
• Limit IMAP access: Use app-specific passwords when available
• Secure storage: Restrict file permissions on certificates and .env

🧪 Development

Commands

# Run with arguments
amelis-smime-decrypt --subject "Auftrag" --output ./output_directory

# Format code
black src/

# Run tests
pytest

# Run tests with coverage
pytest --cov=amelis_smime_decrypt --cov-report=term-missing

# Verbose test output
pytest -v

📚 Architecture

Modular library structure in src/amelis_smime_decrypt/:

Core Modules

1. certificate.py - SMIMECertificate class for P12/PFX certificate loading
2. imap.py - MailboxClient class for IMAP operations with context manager support
3. smime.py - decrypt_email() function for S/MIME decryption
4. attachment.py - extract_attachments() function for PDF extraction
5. cli.py - CLI entry point with argparse support

Key Dependencies

• endesive - S/MIME decryption (RSA-OAEP support)
• cryptography - Certificate/key handling
• imapclient - IMAP protocol wrapper
• python-dotenv - Environment configuration
• pypdf - PDF data extraction

📝 License

This project is licensed under the GPL v3.0 License or later.

🤝 Contributing

Pull requests are welcome! Feel free to fork and submit PRs.

📧 Support

For issues, please open a GitHub Issue.