With the quantum computational paradigm rapidly developing across the world, new vulnerabilities on currently deployed cryptography protocols are to be taken in consideration. A possible answer to said vulnerabilities is using quantum technologies on cryptography. For a quantum-assisted cryptography protocol, key pairs can be generated via quantum state measurements. This protocol is known as quantum key distribution, of extended use for providing security against any algorithm-based attack to the keys. Ensured the key protection against eavesdroppers, a QKD-assisted protocol can focus its security analysis on party behaviour. Depending on the protocol rules and steps to follow, users can attempt attacks on it with the purpose of causing disagreement or misunderstanding between parties. In this work, we present a simulation environment for a hybrid, quantum-assisted digital signature (QDS) protocol. The configurations available for the simulated network as well as the digital signature protocol make it possible to design specific communication scenarios, such as attacks on the message integrity, forging and repudiation attempts or noisy communication across the quantum channels.

The rapid technological advances in the field of quantum communications and the arrival of quantum computers, with a sufficient number of qubits to break the most used encryption algorithms used to date will change the Internet paradigm, as we know it today. Research centers, universities, industries and governments are working hard on the development of more scalable and efficient quantum communications networks, as well as the standardization of protocols, processes and interfaces needed for its industrialization. Many are the definitions of what will be the quantum Internet of the future (its architecture and components), but we offer a more relaxed definition of this concept, so that it is already possible to have a primitive QI with the technology available today, but without all the functionalities and components that will have in the future. As an example, the Madrid Quantum Network meets the requirements of this basic QI, proving to be a first step towards more complex architectures and functionalities. In addition, this concept has direct application as an intranet in restricted military environments, where high levels of security are required and whose extension is limited to metropolitan areas.