**Quantum key distribution for modern telecommunication networks**

Emerging technologies such as Internet of Things, Artificial Intelligence, Blockchain, or Bitcoin, have put privacy and integrity of digital data in the spotlight. In modern cryptography, data is encoded and protected by using hard-to-solve mathematical algorithms, such as the factorization of large numbers. However, modern cryptography is currently facing a serious threat: the advent of quantum computers with enough computational capabilities could break these mathematical algorithms.

The field of quantum information offers a tool that reinforces the security of digital data and makes it secure against quantum computers. This tool is called quantum key distribution (QKD). The idea of QKD is to distribute quantum states between two parties to generate a shared secret key that can be used to encode information. In QKD, the security of the key relies on fundaments on quantum physics and not on mathematical algorithms, providing a way to protect data against advances in computational capabilities.

Researchers at ICFO are developing a QKD prototype based on a technology called continuous variable QKD (CV-QKD). In contrast to other quantum encryption systems, CV-QKD uses similar schemes and components to those found in modern optical telecommunication networks. Thus, this technology could be integrated into a realistic telecom environment, coexisting with classical networks and without comprising data traffic. Such game-changing technology facilitates the deployment of QKD systems at a global-scale.