The importance of Post-Quantum Cryptography for eID documents

Cryptography is what allows us to protect sensitive data and communications and is foundational to how our modern world works. The power of quantum computing, deployed in a brute force manner, means that the resilience of many of the algorithms we’ve used for decades to protect data is now under question. 

Current mechanisms used for authentication, digital signatures and trust chains in identity documents are particularly vulnerable because they rely on asymmetric cryptography like RSA and ECC. Also known as public key cryptography, these mechanisms work by creating a pair of keys - one public and one private. Anyone can use a public key to encrypt data, but only the holders of the corresponding private key can decrypt that data. Although slower and more resource intensive than their symmetric equivalents, asymmetric approaches are used when security is paramount, such as securing communications within an open system, or encrypting sensitive data. 

For governments designing, deploying and managing electronic identity schemes, the prospect of the encryption it relies on being broken is a huge challenge to the trust these systems depend on. Threat actors could use it to break government signature keys, and forge valid false electronic citizen profiles. 

They could also break ID authentication keys and access confidential data stored in the identity documents. From there, they can steal identities or forge digital signatures to impersonate someone else, and access government services illegally.

In the immediate term, organisations shouldn’t assume their existing encrypted data is secure just because the mechanisms aren’t yet accessible to break it. The threat of ‘Harvest Now, Decrypt Later’ attacks, where threat actors steal encrypted and unreadable sensitive data now, with a view to later being able to decrypt and make use of it, still lurks.

This all makes the transition to PQC vital to start now, as identity documents have long lifecycles and interoperability constraints to consider and factor in. Early preparation is crucial to avoid rushed implementations later. 

Luckily, the post-quantum cryptography standards that organisations need to switch to are no longer theoretical. NIST finalised its first PQC algorithm selection in 2024, enabling governments and international bodies to begin updating identity and travel document regulations to address emerging quantum threats.  

The International Civil Aviation Organization (ICAO) and the European Union are  revising cryptographic requirements for civil identity and travel documents,  working closely with NIST and other international standardisation bodies to ensure interoperability and seamless cross-border travel. 

Making the upgrade starts with a comprehensive inventory of all cryptographic resources across internal and external solutions, along the full lifecycle of identity document production and issuance.  

With 10-year validity, identity documents issued today risk exposure to future quantum threats. Migrating to a hybrid scheme, combining traditional and quantum-safe algorithms is recommended to maintain security during the transition period. Adopting agile documents that support seamless in-field cryptographic updates is essential to prevent costly recalls and service disruptions.Pilots will need to be launched to evaluate the impact on the full chain of switching to PQC – from HSMs through to  identity documents, verification use cases and access to government e-services. Bringing PQC into large field deployments can take several years - early action is critical. 

Thales is actively supporting this transition, delivering key breakthroughs. Building on its  long-standing expertise in secure document issuance, Public Key Infrastructures (PKI) and digital identity infrastructures, Thales is a key contributor to PQC migration strategies. It works closely with the US NIST on PQC standards, and co-authored the Falcon digital signature algorithm, selected as part of NIST’s PQC standardisation process. 

As an early adopter of crypto agility across its product portfolio, Thales enables a seamless transition from classical to post-quantum cryptography, avoiding disruptive and costly ‘rip-and-replace’ approaches.

A recent illustration is the MultiApp 5.2 Premium PQC, the first European quantum-safe smart card to achieve Common Criteria certification, awarded by ANSSI, France’s national cybersecurity agency. With new generation cryptographic algorithms, ID documents can be protected from attacks by quantum computers.