TimestaMPC

A multi-party timestamping server created as a semestral project for the Security Technologies course at FI MUNI.

Overview

The project consists of three parts:

• The signer server (written in Rust)
• The manager server (written in Python)
• The client application (written in Python)

To get a document timestamped, the client connects to the manager who then directs the signing process by communicating with signers.

Prerequisites

In order to build the project, you need to have:

• Rust, version 1.59 or higher;
• Python, version 3.10 or higher.

Build

Install necessary Python packages:

pip install -r requirements.txt

Compile the signer server source code:

cd signer
cargo build --release

Setup

We assume that the signers and the manager are able to exchange their public keys in advance, via a secure channel. For testing purposes on a single machine, you can use the generate_keys.py script:

python generate_keys.py 3 setup

This will generate asymmetric key pairs for 3-party ECDSA and store them in the setup directory.

The config directory of this repository contains example configuration files for 2-out-of-3 threshold ECDSA timestamping. These configuration files may be changed depending on the used setup.

For instance, to set up 2-out-of-2 ECDSA timestamping with key refresh, we would use the following configuration file manager.cfg for the manager:

{
  "num_parties": 2,
  "threshold": 2,
  "host": "127.0.0.1",
  "port": 15555,
  "refresh": true,
  "private_key": "setup/manager-key",
  "signers":
  [
    {"index": 0, "host": "127.0.0.1", "port": 30000, "public_key": "setup/signer0-key.pub"},
    {"index": 1, "host": "127.0.0.1", "port": 30001, "public_key": "setup/signer1-key.pub"}
  ]
}

For the first signer, we would use the following configuration signer0.cfg:

{
  "index": 0,
  "host": "127.0.0.1",
  "port": 30000,
  "num_parties": 2,
  "threshold": 2,
  "acceptable_seconds": 60,
  "private_key": "setup/signer0-key",
  "signers":
  [
    {"index": 0, "public_key": "setup/signer0-key.pub"},
    {"index": 1, "public_key": "setup/signer1-key.pub"}
  ],
  "manager_public_key": "setup/manager-key.pub",
  "data_folder": "data"
}

Intended usage

When the setup is complete, we can run the signers, supplying a configuration file to each:

./signer/target/release/signer config/signer0.cfg

Next, we can execute the manager. When it starts, it immediately establishes a connection with the signers in order to generate a distributed ECDSA private key.

./manager/main_server.py config/manager.cfg

At this point, the manager is ready to accept timestamping requests. To have a document signed, use the client application:

cd client
./client.py sign document.txt

As a response, the client receives a JSON dictionary containing the timestamp, server certificate, and the signature itself. The result can be immediately validated using the client verify command:

./client.py sign document.txt | ./client.py verify document.txt

Authors

The project is developed by Stanislav Boboň, Jiří Gavenda, and Pavol Žáčik.