Poor Man’s Crypto Card (PMCC)

Utilities for creating and using SLE-series smart-card images such as:

• SLE4442 (256-byte)
• SLE4428 (1024-byte)

The project provides command-line tools and optional GUI interfaces for:

• Creating card images
• Signing and verifying files
• Encrypting and decrypting messages
• Extracting public keys from cards

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Security Warning

PMCC is not secure key storage.

Card images contain raw key material. Anyone who obtains:

• the card image file, or
• a dump of the card

can copy the encrypted seed and attempt to brute-force the password.

This project provides tools for working with keys, but does not protect them against theft or extraction.

Treat card dumps and images as sensitive data and store them securely.

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Project Structure

Component	Purpose
card_crypto.py	Perform cryptographic operations using a key stored on a physical card
make_card_image.py	Build a card image containing a keypair and metadata
make_card_image_gui.py	GUI tool for creating card images
card_crypto_gui.py	GUI interface for signing, encrypting, verifying, and editing messages
core/	Shared utilities (PC/SC communication, configuration, language support)
drivers/	Low-level SLE card drivers
model/	Data container classes used by tools and GUI
i18n/	Translation files

The GUI defaults to English (en). You can change the language by editing the language setting in the configuration file.

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Requirements

Install Python dependencies:

python3 -m pip install -r requirements.txt

You will also need:

• PC/SC middleware (pcsclite)
• A compatible smart-card reader

Without PC/SC installed, the pyscard module will fail to load.

Scripts require Python 3.8+ and were primarily tested on Linux, but should work on other platforms with PC/SC support.

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Card Image Format

The utilities assume the following memory layout:

0x000-0x01F   header (unused)
0x020-0x05F   encrypted Ed25519 private key (64 bytes)
0x060-0x07F   Ed25519 public key (32 bytes)
0x080-0x0FF   metadata (128 bytes)

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Command-Line Usage

Scripts can be run directly:

./card_crypto.py
./make_card_image.py

Passwords are always requested interactively and are never stored.

Public keys extracted from cards are automatically saved to:

~/.pmcc/

Generated files use restrictive permissions (600 / 700) when possible.

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Creating a Card Image

make_card_image.py builds a card image for an SLE card.

Default output is 256 bytes (SLE4442). Use --type sle4428 for 1024-byte images.

Example

python make_card_image.py \
    --blank blank_dump.bin \
    --priv private_enc.der \
    --pub public.raw \
    --metadata First=Alice Last=Smith expire=2026-12-31 \
    -o card.bin

For a 1024-byte card image:

python make_card_image.py --type sle4428 \
    --blank blank_dump.bin \
    --priv private_enc.der \
    --pub public.raw \
    --metadata First=Alice Last=Smith expire=2026-12-31 \
    -o card_4428.bin

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Interactive Mode

If arguments are omitted you can run the tool interactively:

python make_card_image.py --interactive

The tool can also generate a new keypair automatically.

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Metadata

Metadata fields can be provided:

• directly on the command line
• through a JSON file (--metadata-file)

Allowed metadata fields are defined in:

metadata_fields.json

You can supply your own schema using:

--metadata-schema

If the schema cannot be found, the default fields are used:

First
Last
expire
clearance
Issue_Date

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Cryptographic Operations

card_crypto.py interacts with a live smart card via PC/SC.

Card image files are not supported.

Supported commands:

Command	Description
extract-public	Save the card’s public key
sign	Sign a file
verify	Verify a signature
encrypt	Encrypt data using the card key
decrypt	Decrypt data

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Extract Public Key

python card_crypto.py extract-public

The public key is automatically saved to:

~/.pmcc/

The filename is generated from card metadata.

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Sign a File

python card_crypto.py sign --input message.txt

Creates a signature file:

message.txt.sig

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Verify a Signature

python card_crypto.py verify \
    --pubkey public.pem \
    --input message.txt \
    --sig message.txt.sig

If verification fails, the tool prints diagnostic information to help identify incorrect inputs.

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GUI Applications

Two optional Qt interfaces are included.

Both require PySide6.

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Card Image Creator (GUI)

Launch with:

python make_card_image_gui.py

Features:

• Select blank card dump
• Load or generate key pairs
• Enter metadata through structured fields
• Automatic filename generation
• Optional protection map generation
• Status and log output

Default output filename:

card_image_<YYYYMMDD>.bin

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Crypto GUI

Launch with:

python card_crypto_gui.py

Features:

• Automatically detects PC/SC card readers
• Supports signing, encryption, verification, and key extraction
• Includes a built-in message editor

The interface allows you to:

• scan for readers
• connect to a card
• perform cryptographic operations
• view log output

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Built-in Editor

The GUI includes a Markdown-aware editor for composing and processing messages.

Capabilities include:

• Markdown formatting
• WYSIWYG preview
• file open/save
• encryption and decryption
• signing and verification
• inserting and extracting public keys

The editor starts in preview mode, rendering Markdown as formatted text.

A Preview toggle allows switching between:

• raw Markdown
• rendered rich text

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Important Editor Notes

When performing crypto operations:

• the editor automatically switches to raw Markdown mode
• this prevents preview rendering from corrupting encrypted blocks or signatures

Signature blocks are also protected during preview rendering to prevent formatting issues.

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Development Notes

• Written in plain Python
• No build step required
• Shared logic is located in:

core/
drivers/
model/

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Acknowledgements

Some low-level code was adapted from the sle-suite-pro project developed by Wikilift. Their work enabled communication with blank SLE cards and image dumps.

The card images produced by this software are designed to be imported into sle-suite-pro and writen directly to a card.

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