Crypto-agility: Preparing for post-quantum decryption

Quantum computing is maturing rapidly and could achieve sufficient capacity to break current encryption keys by the end of this decade—if not sooner. While experts disagree on the specific date, there is no doubt that it will eventually defeat current encryption models. Adversaries know this and are stockpiling stolen encrypted data with the expectation of decrypting it in the near future.

Given this imperative, the White House has issued a series of National Security Memoranda requiring federal agencies to prepare for this fast-arriving threat. As part of their preparation, agencies must adopt a nimble approach to cryptographic security known as crypto-agility, which will enable them to replace or update compromised keys and certificates without impacting the functions of mission-critical infrastructure.

While federal agencies must begin their journey to crypto-agility today, the path forward to future-proof security is well-defined and sustainable. By embracing crypto-agility, agencies can operate confidentially as they continue to digitize their operations.

Before 1994, the RSA cryptosystem was widely considered to be completely impenetrable and had proven to be so for nearly four decades. A single discovery—Shor’s algorithm—changed everything, demonstrating that quantum computers could conceivably crack RSA and other asymmetric public-key encryption systems.

Since then, cryptosecurity experts have held the threat at bay by increasing the minimum length for uncrackable keys, allowing RSA to remain the most widely used public-key encryption system in the world.

RSA is vulnerable to brute force attacks because it uses asymmetric keys, one of which is public. Subsequent cryptosystems—specifically the Advanced Encryption Standard (AES)—rely on symmetric private keys. Theoretically, AES could also be cracked via brute force using an accelerator known as Grover’s algorithm. To do so, however, a threat actor would need an exponentially more sophisticated quantum computer than that required to crack RSA encryption.

AES-256—the most current AES standard with the longest keys, which are currently used to safeguard top secret government data—is considered quantum safe for now. Unfortunately, because it would require large-scale key distribution, AES is not a suitable replacement for public key cryptography in all federal agency scenarios.

By the end of this decade or even earlier, quantum computers may be able to break current RSA encryption keys. The day that happens, every platform, application, device, file, and email encrypted via RSA or other vulnerable cryptosystems will be at risk.

Our nation’s adversaries know this, too, and are working to steal encrypted data today with the intent of decrypting it later—the “Hack Now, Crack Later” strategy. Thus, any government data stolen now can be presumed to be compromised.

By harnessing quantum mechanical phenomena such as superposition and entanglement rather than binary functions to perform computational operations, quantum computers are exponentially faster and more powerful than even the largest classical computers.

Global investment in quantum science grows year over year, as governments, venture capitalists, and multinational technology companies including Alphabet, IBM, and Microsoft seek to establish technical superiority and market dominance in quantum computing.

More than just a replacement for existing encryption technologies, crypto-agility enables an organization to quickly switch between algorithms, cryptographic primitives, and other encryption mechanisms. Agencies that adopt a crypto-agile approach will be able to replace compromised keys and certificates without impacting the functions of mission-critical infrastructure.

Crypto-agility simultaneously solves for current and future threats. Key advantages include:

At the heart of crypto-agile strategy is a defensive but practical mindset powered by ground truth. Crypto-agile strategy factors in the full scope of the agency’s enterprise IT and operational technology and the current cryptography ecosystem that protects its digital assets. The strategy encompasses the agency’s assessment and authorization (A&A) policies and procedures, which may require review and updating to ensure that future systems comply with the 2022 White House mandates.

Crypto-agility combines a strategy, a platform, and an operating model. To operationalize the strategy, agencies will need an enterprise platform that uses a lightweight and scalable post-quantum framework API to integrate all endpoints throughout the network infrastructure—computers, mobile devices, terminals, etc.—as well as data stores, cloud storage and computing services, and supervisory control and data acquisition (SCADA) systems.

The purpose of a crypto-agile platform is to orchestrate security protocols and algorithms, provisioning quantum-safe encryption for data at rest and in flight as well as code signing for software updates. The API builds agility into the enterprise by enabling use of classical, hybrid, and fully quantum-resistant algorithms.

To implement and maintain crypto-agility, agencies may need to modify their cyber operating models and provide training for systems administration personnel. Modifications include integrating crypto-agile APIs and configuring them within devices and systems, as well as updating agency policies and security processes that govern authority to operate.

A crypto-agile system is one that is aware of all cryptography within the enterprise. The platform and operating model support routine collection of cryptographic intelligence to quickly identify rogue cryptography, compromised algorithms, and other associated threats. The agency’s cyber operating model must accommodate new feedback loops to ensure that this intelligence reaches security and organizational leaders responsible for the cryptography ecosystem.

Critical outcomes of the inventory process will support agency planning and implementation efforts by:

• Providing critical inputs to formulate budgetary requests to plan and implement a crypto-agile platform and operating model
• Identifying systems with legacy or out-of-date cryptographic standards and other priority security updates
• Prioritizing updates to protect HVAs with quantum-resistant algorithms (lattice-based and hash-based cryptography) to improve resiliency against quantum attacks

By adopting crypto-agility as a strategy, platform, and operating model, federal agencies can safeguard their information systems and communications against the post-quantum threats that are imminent today—and successor threats yet to be defined.

As federal agencies undertake efforts to comply with immediate-term requirements laid out by the White House, they can simultaneously perform the full scope of discovery needed to achieve crypto-agility—all as part and parcel of ongoing initiatives to achieve Zero Trust architecture and implement a modern, secure IT environment.

The aim—and result—of these efforts will be to imbue our Nation’s cyber, economic, and national security with unprecedented and self-perpetuating resiliency.