Cryptography is a fundamental digital security technology at the core of digital trust. Although most people rarely notice its use and barely understand how it works, it is the technical building block supporting user trust in their devices, software, and communications for personal, commercial, legal, business, governmental and other purposes. Cryptography supports the confidentiality and integrity of data in communication (in transit) and in storage (at rest). Digital signatures provide authenticity of information and prevent an involved party from denying its responsibility related to that information, such as authoring or sending it.

This report introduces cryptography to policymakers and includes key concepts such as symmetric and asymmetric cryptography, public key infrastructure, and end-to-end encryption. It discusses advancements in homomorphic encryption, which allows computations to be performed on encrypted data without decrypting it first and accessing the secret key. Often described as the 'holy grail of cryptography', homomorphic encryption remains a promising area of research rather than a fully developed technology.

The report also addresses quantum technologies, which could pose a threat to the foundations of public key cryptography, potentially undermining trust in the digital ecosystem. While current quantum computers are far from causing such disruptions, a transition to quantum-resistant (or post-quantum) cryptography is essential today to address their future impact. Additionally, quantum cryptography shows significant promise for secure communications, but is not yet suitable for sensitive applications.