Multi-signatures enhance a system's security by decentralizing private key storage. This decentralization requires the use multiple devices. A convenient approach is to use a user's smartphone together with a cryptographic smartcard communicating over a wireless interface. However, smartcards' restricted programming interfaces provide only limited support for the computation of relevant protocols.

The goal of this thesis is to assess the feasibility of computing state-of-the-art multi-signature protocols on cryptographic smartcards and demonstrate their usage in practical applications via a threshold cryptography platform (https://meesign.crocs.fi.muni.cz/).

The work on the thesis will comprise the following steps:

• Survey of current EC-based multi-signature schemes and their computation requirements.
• Implementation of a selected scheme on cryptographic smartcards.
• Proposal of possible optimizations (e.g., secure offloading to the host device).
• Performance evaluation of the resulting implementation.
• Integration of the implementation within the threshold cryptography platform.
• Demonstration of its usage within a real-world application.