Quantum computers are no longer a distant prospect. In 2026, governments and technology companies worldwide are investing in the development of quantum hardware that will, within the foreseeable future, be capable of breaking current encryption standards. This means that organizations relying on secure communications must already be thinking about quantum-safe encryption. Which methods offer genuine protection against quantum attacks? This article provides a clear overview of seven proven encryption methods that can withstand the threat of quantum computing.
Why classical encryption falls short against the quantum threat
Most classical encryption standards, such as RSA and elliptic curve cryptography (ECC), base their security on mathematical problems that are practically unsolvable for traditional computers such as factoring large numbers into prime factors. A powerful quantum computer can perform these kinds of calculations exponentially faster using algorithms such as Shor’s algorithm.
This makes a large portion of current network security vulnerable. Attackers can already intercept and store encrypted traffic today, with the expectation of decrypting it later using a quantum computer. This strategy, known as “harvest now, decrypt later,” is a concrete threat to organizations that work with sensitive or long-term confidential data.
Post-quantum cryptography is the answer: a category of encryption methods that are also resistant to quantum attacks. The American National Institute of Standards and Technology (NIST) published the first official post-quantum standards in 2024, further underscoring the urgency of migration.
1: Lattice-based cryptography
Lattice-based cryptography is currently the most promising direction within post-quantum cryptography. Its security rests on mathematical problems in high-dimensional lattices, such as the Shortest Vector Problem (SVP), for which no efficient quantum algorithms exist.
CRYSTALS-Kyber, a lattice-based algorithm, has been selected by NIST as the standard for quantum-safe key exchange. It combines strong security with relatively compact key sizes and fast computation, making it practically deployable in network environments.
Lattice-based methods are suitable for a wide range of applications, from secure communication protocols to encryption of stored data. Organizations looking to migrate now to protection against quantum threats often start with lattice-based algorithms due to their maturity and broad support.
2: Hash-based digital signatures
Hash-based signatures provide quantum-safe authentication based on cryptographic hash functions. Because their security depends solely on the properties of hash functions and not on number-theoretic problems, they are inherently resistant to quantum attacks.
XMSS (eXtended Merkle Signature Scheme) and SPHINCS+ are well-known examples. SPHINCS+ has also been standardized by NIST as a post-quantum signature scheme. The algorithm produces relatively large signatures compared to classical methods, but in return offers a solid security guarantee.
Hash-based signatures are particularly well suited for environments where authenticity and integrity are paramount, such as software updates, certificate management, and critical infrastructure communications. They are less suitable for applications that require very small signatures.
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3: Code-based cryptography
Code-based cryptography relies on the mathematical complexity of error-correcting codes. Decoding arbitrary linear codes without knowledge of their structure is a problem that has been considered quantum-resistant for decades. The McEliece cryptosystem, developed in 1978, is one of the oldest examples and has withstood all cryptanalysis since its introduction.
The drawback of classical code-based systems is the large public key sizes, sometimes several megabytes. More modern variants such as BIKE and HQC attempt to address this with more compact representations, but there are always trade-offs between key size, speed, and security level.
For environments where security outweighs bandwidth or storage capacity such as critical infrastructure or government networks, code-based cryptography offers a proven and robust alternative to classical encryption methods. Exploring a broad range of security solutions can help organizations identify the right fit for their specific risk profile.
4: Multivariate cryptography
Multivariate cryptography bases its security on solving systems of multivariate polynomial equations over finite fields. This is a mathematical problem considered NP-hard, for which no efficient quantum solutions are known.
Multivariate systems are particularly fast at generating and verifying signatures, making them attractive for applications with strict performance requirements. Rainbow and GeMSS are well-known examples, although Rainbow was compromised by a classical attack in 2022, demonstrating that not every multivariate scheme is equally robust.
Multivariate cryptography is best suited for digital signatures in environments with limited computing power, such as IoT devices or embedded systems. Careful selection of the specific scheme is essential, as security depends heavily on the chosen parameters and implementation details.
5: Isogeny-based cryptography
Isogeny-based cryptography is a relatively new branch of post-quantum cryptography that makes use of mathematical relationships between elliptic curves. It offers very compact key sizes compared to other post-quantum methods, making it attractive for bandwidth-efficient applications.
SIKE (Supersingular Isogeny Key Encapsulation) was long considered a promising candidate, but was broken by a classical attack in 2022. This illustrates that isogeny-based cryptography is still evolving and that existing schemes require further research before being widely deployed.
Despite this setback, isogeny-based cryptography remains an active area of research. For organizations currently migrating to quantum-safe encryption, it is advisable not to rely on isogeny-based methods as a primary solution for now, while continuing to monitor developments closely.
6: Quantum Key Distribution (QKD)
Quantum Key Distribution is a fundamentally different approach to quantum-safe communication. Rather than relying on mathematical complexity, QKD uses the laws of quantum mechanics itself to distribute keys. Any attempt to eavesdrop on the key exchange disturbs the quantum state of the photons, making it immediately detectable.
QKD offers theoretically unbreakable security, regardless of an attacker’s computing power. However, it requires specialized hardware such as quantum transmitters and receivers and is currently deployable primarily over fiber-optic connections or via satellite links. The maximum distance without intermediate repeaters is a practical limitation.
QKD is most relevant for organizations with extremely high security requirements, such as government agencies, financial institutions, and critical infrastructure operators. Combining QKD with Layer 1 and Layer 2 encryption solutions provides a powerful layered security architecture. Organizations seeking end-to-end protection may also benefit from managed security services that cover ongoing monitoring and threat response.
7: Layer 1 and Layer 2 encryption for networks
Layer 1 and Layer 2 encryption secure data at the physical and data link layers of the OSI model. This means all data is encrypted before it reaches higher-level protocols, regardless of which applications or services run on top.
Layer 1 encryption operates at the level of the fiber-optic connection itself, providing protection that is completely transparent to higher network layers. Layer 2 encryption, such as MACsec (IEEE 802.1AE), encrypts Ethernet frames and is widely deployable in enterprise and carrier networks. Both methods can be combined with post-quantum algorithms for key exchange, making them future-proof.
For networks transporting sensitive or business-critical data, Layer 1 and Layer 2 encryption provide a fundamental security layer that operates independently of application-level security. This is particularly valuable in environments such as data centers, hospitals, transportation networks, and critical infrastructure, where continuity and confidentiality must go hand in hand.
Choosing the right encryption for future-proof networks
There is no one-size-fits-all solution for quantum-safe network security. The right choice depends on several factors:
- Type of data and confidentiality duration: Is this data that needs to remain confidential for decades? If so, immediate migration to post-quantum cryptography is urgent.
- Performance requirements: Some post-quantum algorithms demand more computing power or generate larger keys. This must be weighed against the capacity of existing hardware.
- Network architecture: Layer 1 and Layer 2 encryption are most effective when you have full control over the network infrastructure. For distributed environments, software-based post-quantum algorithms may be a better fit.
- Hybrid approach: Many organizations opt for a hybrid strategy in which classical and post-quantum algorithms are deployed in parallel until the new standards are fully validated.
- Compliance and standards: Follow the NIST post-quantum standards as a guide. CRYSTALS-Kyber for key exchange and CRYSTALS-Dilithium or SPHINCS+ for digital signatures are now officially standardized.
A phased migration is the most practical approach for most organizations. Start with an inventory of which systems and connections are most vulnerable, prioritize based on risk, and incrementally implement quantum-safe encryption where the threat is greatest.
How we help with quantum-safe network security
The transition to post-quantum cryptography requires technical expertise, a clear understanding of your current infrastructure, and a well-considered migration strategy. We support organizations at every step of this process, from the initial risk assessment to the implementation of quantum-safe encryption in your network.
What we offer in the area of network security:
- Advice on the right post-quantum cryptography standards for your environment
- Implementation of Layer 1 and Layer 2 encryption on fiber-optic and Ethernet infrastructure
- Quantum Key Distribution (QKD) for environments with the highest security requirements
- Vendor-independent advice with solutions from partners such as Cisco, Nokia, and Huawei
- End-to-end support: from design and implementation to management and monitoring
- Specialized expertise for critical sectors such as healthcare, transportation, data centers, and government
Want to know how vulnerable your current network security is to quantum attacks, and what steps you can take to become future-proof? Contact us for a no-obligation conversation with one of our security specialists.
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