Setting Up a PQC Vendor and Library Evaluation Process

The cryptographic algorithms securing today's blockchains—primarily Elliptic Curve Cryptography (ECC) and RSA—are vulnerable to attacks from sufficiently powerful quantum computers. This threat, known as Store Now, Decrypt Later (SNDL), means encrypted data or blockchain transactions recorded today could be decrypted in the future. For Web3 protocols handling billions in assets and sensitive user data, migrating to Post-Quantum Cryptography (PQC) is not optional; it's a critical security imperative for long-term viability.

Choosing a PQC solution is complex. The landscape includes NIST-standardized algorithms like Kyber (for key exchange) and Dilithium (for signatures), alongside alternative schemes. Each comes with trade-offs in performance, key/signature size, and implementation maturity. Furthermore, libraries from different vendors (e.g., Open Quantum Safe, liboqs, or commercial providers) vary in API design, language support, and audit status. Selecting a library without a formal evaluation can lead to integration headaches, performance bottlenecks, or unforeseen security flaws.

A structured vendor and library evaluation process mitigates these risks. It provides a repeatable framework for teams to assess technical fit, security posture, and maintenance commitments. This process moves the decision from an ad-hoc choice to a data-driven one, considering factors like benchmark results on your target hardware, the quality of the library's cryptographic side-channel defenses, and the responsiveness of the vendor's support team. For developers, this translates to confidence in their stack's future-proofing.

This guide outlines a practical evaluation workflow. We'll cover how to define your security and performance requirements, create a shortlist of candidate libraries, and conduct hands-on testing. The goal is to equip your team with a methodology to select a PQC library that is not only quantum-resistant but also production-ready for your specific application, whether it's a new L1 blockchain, a smart contract platform, or a decentralized identity protocol.

Before evaluating specific PQC libraries, you must define your technical prerequisites and security requirements. This includes identifying your application's threat model, performance benchmarks (e.g., latency under load, memory footprint), and compliance needs such as FIPS 140-3 or specific industry standards. You should also inventory your current cryptographic dependencies and deployment environments (e.g., cloud, IoT, mobile) to understand integration complexity. A clear set of prerequisites acts as a filter, ensuring you only spend time on libraries that meet your core operational and security needs.

Assembling a cross-functional evaluation team is essential for a holistic assessment. The team should include: a cryptography expert to analyze algorithm security and implementation correctness, a software engineer to assess API design, documentation, and integration effort, a performance engineer to conduct benchmarking across target platforms, and a security auditor to review code quality and vulnerability history. Including a project manager to coordinate testing and decision timelines is also recommended. This structure ensures technical depth, practical feasibility, and security rigor are all represented.

The evaluation process itself should be methodical. Start with a high-level screening of candidate libraries (e.g., Open Quantum Safe's liboqs, Google's Tink, commercial vendors) against your prerequisites. For libraries that pass, proceed to a hands-on proof-of-concept (PoC). The PoC should test real-world scenarios: generating and exchanging keys, signing/verifying messages, and establishing TLS-like sessions. Use standardized test vectors from NIST or the library's own test suite to verify correctness. Document all findings, including ease of integration, any build issues, and initial performance metrics.

Benchmarking must go beyond synthetic micro-benchmarks. Measure performance in the context of your application, such as the impact on end-to-end API call latency or bulk data encryption throughput. Pay particular attention to operations that are critical for your user experience. Furthermore, assess the library's ecosystem health: review the frequency of commits and releases, responsiveness to issues on GitHub, clarity of security advisories, and the availability of commercial support options. A library with an active maintainer community is often a lower long-term risk.

Finally, establish clear evaluation criteria and scoring. Create a weighted rubric based on your prerequisites, scoring each library on factors like security assurance, performance, developer experience, and maintenance posture. This quantitative approach, combined with the qualitative insights from your team's PoC, provides a defensible basis for selection. The output should be a recommendation report that details the top candidate(s), justifies the choice with data, and outlines a phased migration plan from your current cryptographic stack to the new PQC library.

The first step is a threat model analysis. Determine which cryptographic components are vulnerable to quantum attacks. For most blockchain protocols, this includes the digital signatures used for transaction authorization (e.g., ECDSA, EdDSA) and potentially the hash functions within your consensus mechanism or smart contracts. A protocol using BLS signatures for validator attestations, for instance, has a different PQC migration path than one relying on ECDSA for user wallets. Document every component, its current algorithm, and its function.

Next, define your performance and integration constraints. PQC algorithms are computationally heavier than their classical counterparts. You must establish acceptable benchmarks for signature size, verification speed, and key generation time within your network's parameters. For a high-throughput L2 rollup, verification latency is critical. For a store-of-value L1, signature size impacting block weight may be the primary concern. Use tools like the NIST PQC Standardization Project's performance reports to set realistic baselines.

Finally, formalize your evaluation criteria. This goes beyond just algorithm selection. Create a scorecard that includes: algorithm maturity (NIST standardization status), library quality (code audit history, active maintenance), language support (Rust, Go, C++), and side-channel resistance. For example, you might prioritize libraries that implement CRYSTALS-Dilithium with constant-time execution to prevent timing attacks. This structured criteria will objectively guide your vendor and library assessment in the next steps.

Begin by establishing a formal vendor and library evaluation framework. This framework should define your core criteria, which typically include algorithm support (e.g., CRYSTALS-Kyber, CRYSTALS-Dilithium), implementation maturity, licensing (open-source vs. proprietary), performance benchmarks, and the quality of documentation. For blockchain use, pay special attention to signature size and verification speed, as these directly impact transaction costs and network throughput. Create a scoring matrix to objectively compare different options like Open Quantum Safe's liboqs, Amazon's AWS libcrypto, or vendor-specific SDKs.

The security audit is the most critical phase. Do not rely solely on a library's reputation. Require a recent, independent audit from a recognized firm (e.g., Trail of Bits, NCC Group) that specifically reviews the PQC implementation. Scrutinize the audit report for issues like side-channel vulnerabilities, improper randomness generation, and adherence to the NIST FIPS 203, 204, and 205 draft standards. For open-source libraries, examine the project's security disclosure policy, bug bounty program, and the responsiveness of its maintainers to reported issues on GitHub. A lack of transparent security practices is a major red flag.

Next, conduct a manual code review of the library's core cryptographic functions. Focus on the key generation, encryption/signing, and decryption/verification modules. Look for code quality indicators: Is the memory management secure (no buffer overflows)? Is constant-time execution enforced to prevent timing attacks? Are dependencies minimal and well-understood? Use static analysis tools like Semgrep or CodeQL with custom rules for cryptographic code to automate part of this process. For example, a review might check that a Dilithium implementation uses a constant-time mod q operation.

Finally, perform integration testing within a simulated blockchain environment. Clone the library and integrate it into a test version of your smart contract or node software. Benchmark its performance under realistic load, measuring gas costs for on-chain verification or CPU cycles for off-chain signing. Test interoperability: can signatures produced by Library A be verified by Library B, as per the standard? This step often reveals practical issues like memory overhead, compiler compatibility, and build system complexity that aren't apparent in isolation. Document all findings and deviations from expected behavior in your evaluation matrix to inform the final selection.

The first step in your evaluation is to define a clear testing environment. This means standardizing your hardware (e.g., AWS c6i.2xlarge instance), operating system (Ubuntu 22.04 LTS), and compiler (GCC 11.3.0) to ensure consistent, reproducible results. You must also select a representative set of cryptographic operations to benchmark. For PQC, this typically includes key generation, signature creation/verification (for algorithms like Dilithium or Falcon), and key encapsulation/decapsulation (for Kyber). Establish baseline metrics by first benchmarking your current classical algorithm (e.g., ECDSA or RSA-2048) under the same conditions.

Next, integrate the candidate PQC libraries into your test harness. For open-source libraries like Open Quantum Safe (OQS) or liboqs, this involves cloning the repository, following its build instructions, and linking it to your benchmarking application. For vendor SDKs, you'll integrate their provided binaries or APIs. Your benchmark should measure throughput (operations per second), latency (time per operation), and memory footprint for each core operation. Use tools like perf or valgrind to profile CPU cycles and heap usage. Document the results in a structured format, such as a CSV file, for easy comparison across different libraries and parameter sets (e.g., Kyber-512 vs. Kyber-768).

Performance is critical, but security validation is paramount. Beyond trusting a library's claims, you should conduct basic correctness and side-channel tests. Run the library's provided test vectors to ensure it produces the correct outputs for known inputs. For a more rigorous check, consider using a differential fuzzing tool like libFuzzer or AFL++ to test for crashes or memory corruption on malformed inputs. While full side-channel analysis requires specialized equipment, you can perform timing-attack resilience checks by measuring if operation runtime varies significantly with secret key material using high-resolution timers.

Finally, synthesize your findings into a decision matrix. Weigh the performance metrics against other crucial factors: code maturity (audit history, GitHub stars/forks), license compatibility (MIT, Apache 2.0, or proprietary), community support (active maintainers, issue resolution time), and API ergonomics for your development team. A library with slightly slower benchmarks but a clean, well-documented API and an active community may be a better long-term choice than a faster but poorly maintained alternative. This structured evaluation process provides the data-driven evidence needed to select a PQC solution that balances performance, security, and maintainability for your specific application.

The first step is to identify the specific license for each candidate library. Common licenses in the cryptographic space include permissive options like Apache 2.0, MIT, and BSD-3-Clause, which allow broad use with minimal restrictions. You may also encounter copyleft licenses like the GNU General Public License (GPL), which requires derivative works to be released under the same license. For example, integrating a GPL-licensed PQC library into a proprietary, closed-source application can create significant legal conflicts. Always verify the license directly from the project's official repository, such as its LICENSE file on GitHub, rather than relying on secondary sources.

Next, perform a compatibility analysis between the library's license and your organization's intended use and existing software stack. This involves checking if the license terms are compatible with your product's distribution model (open-source vs. proprietary), your dependencies' licenses, and your internal compliance policies. Tools like FOSSA, Black Duck, or SCA (Software Composition Analysis) scanners can automate part of this process by generating a Software Bill of Materials (SBOM) and flagging potential license conflicts. For instance, combining code under Apache 2.0 (which includes a patent grant) with code under GPLv3 is generally permissible, but combining GPLv2-only code with Apache 2.0 code is not.

Beyond the base license text, scrutinize any additional legal risks. Review the library's source for cryptographic patent claims, especially for algorithms like Kyber, Dilithium, or SPHINCS+, which may be covered by patents in certain jurisdictions. Check the project's documentation for explicit patent grants or non-assertion pledges, such as those provided by the PQClean project contributors. Furthermore, assess the export control implications; cryptographic software is often subject to regulations like EAR (Export Administration Regulations) in the United States. Using a library from a vendor in a country under trade sanctions could introduce severe compliance risks.

Finally, document your findings and decision rationale in a formal vendor assessment report. This report should catalog each evaluated library, its license, identified risks (patent, export, copyleft), and a clear compatibility verdict. This creates an audit trail for legal and security teams and is crucial for enterprise governance. For open-source libraries, consider engaging with the project community to clarify ambiguous terms or seek written assurances. For commercial vendors, ensure license terms—covering usage rights, liability, support, and algorithm indemnification—are explicitly detailed in the contract before integration begins.

A library's maintenance status is a critical indicator of its security and reliability. Check the project's release history on its repository (e.g., GitHub). Look for regular updates that address security patches, bug fixes, and dependency upgrades. A project with no commits in the last 12 months may be abandoned. Examine the frequency and quality of releases; a steady cadence of minor and patch versions (e.g., v1.2.3, v1.2.4) is more reassuring than sporadic major version jumps without interim support.

Evaluate the health of the open-source community surrounding the library. Key metrics include the number of contributors, the responsiveness to issues and pull requests, and the presence of an active discussion forum or chat. A library maintained by a single individual or a small, inactive team poses a supply chain risk. Review open and closed issues to see how bugs are handled. A high ratio of closed issues and constructive dialogue in pull requests signals a healthy project. Projects under the umbrella of a foundation like the Linux Foundation or Apache Software Foundation often have more sustainable governance models.

For vendor-supplied solutions, scrutiny is equally important. Investigate the vendor's public roadmap for PQC algorithm support and their commitment to migrating their own products. A vendor's involvement in standardization bodies like NIST or IETF is a positive signal. Require clear answers on support lifecycle, deprecation policies, and the provision of updates for emerging cryptanalytic attacks. You must verify claims through third-party audits or certifications, if available.

Establish a concrete evaluation process. Create a scoring rubric for your shortlisted options. Criteria should include: Update Frequency (e.g., commits/month), Issue Resolution Time (median days to close), Community Size (stars, contributors), Documentation Quality, and Vendor Transparency. Use tools like OpenSSF Scorecard or Libraries.io to gather some of this data programmatically. This quantitative approach helps remove bias from the selection process.

Finally, consider the ecosystem and adoption. A library with integrations into major frameworks (like OpenSSL, BoringSSL, or popular programming language package managers) reduces integration overhead. Widespread use in production by other reputable organizations acts as a form of peer review. However, popularity alone isn't enough; balance it with the technical and maintenance factors already assessed to make a resilient long-term choice for your post-quantum cryptography implementation.

This guide has outlined a systematic approach to setting up a PQC vendor and library evaluation process. The key steps involve: defining your application's specific security and performance requirements, creating a standardized evaluation matrix, conducting hands-on integration tests with shortlisted libraries like liboqs, PQClean, or Open Quantum Safe, and establishing a continuous monitoring protocol for algorithm updates from NIST. The goal is to move from theoretical risk assessment to practical, actionable integration planning.

Your immediate next steps should focus on proof-of-concept (PoC) development. Select one high-priority use case within your stack—such as securing wallet-to-node communication or implementing quantum-resistant signatures for a governance module—and implement it using a candidate library. Measure the performance impact on transaction latency and block size, and document the integration challenges. This PoC will provide concrete data to inform broader rollout decisions and budget requests.

For ongoing vigilance, integrate PQC tracking into your existing security workflow. Subscribe to announcements from NIST and IETF, and monitor the development branches of your chosen libraries. Consider using tools like dependabot or renovate to watch for updates to PQC dependencies. The transition to post-quantum cryptography is a marathon, not a sprint; a disciplined, iterative evaluation and integration process is your most reliable defense against future quantum threats.