Algorithms, protocols and key management for protecting data, plus where NIST's post-quantum standards (ML-KEM, ML-DSA, SLH-DSA, HQC) stand in 2026.
Cryptography protects data by making it unreadable to anyone without the right key and by proving that information has not been altered or forged. Encryption is only effective when the right algorithms are chosen, keys are managed carefully and the organisation prepares for changes such as the transition to post-quantum cryptography. This article reviews the essentials that network and security teams need to apply in 2026.
Cryptographic mechanisms serve several distinct goals:
Understanding which goal you need helps you pick the right mechanism. Encrypting a file does not by itself prove who created it, and signing a message does not hide its content.
Symmetric algorithms such as AES use the same key to encrypt and decrypt. They are fast and suited to large volumes of data, for example disk encryption, database encryption or the bulk of a VPN session. Modern deployments favour authenticated modes such as AES-GCM, which provide confidentiality and integrity together.
Asymmetric algorithms such as RSA and elliptic-curve schemes use a public key and a private key. They are slower but solve the key distribution problem: they allow two parties to agree on a shared secret or to verify signatures without having met before. Protocols like TLS combine both approaches: asymmetric cryptography establishes and authenticates the session, then symmetric encryption protects the traffic.
For data in transit, TLS 1.3 should be the default for web services and APIs, with TLS 1.2 kept only where compatibility requires it and configured with strong cipher suites. Older protocols such as SSL 3.0, TLS 1.0 and TLS 1.1 should be disabled. For site-to-site and remote access connections, IPsec and modern VPN configurations apply the same principles.
For data at rest, full-disk encryption protects lost or stolen devices, while database, file or application-level encryption protects data even when an attacker gains access to a running system. Backups must be encrypted too, since they often contain the most complete copy of sensitive information.
Weak or outdated algorithms, such as MD5 and SHA-1 for signatures, DES and 3DES, should be identified and replaced. Misuse of cryptography is also a recurring cause of vulnerabilities: the OWASP Top 10:2025 still lists Cryptographic Failures among the main application risks.
Strong algorithms are useless if keys are exposed. Good key management covers the full lifecycle, as described in NIST SP 800-57:
A sufficiently powerful quantum computer would be able to break RSA and elliptic-curve cryptography. Such a machine does not exist today, but data captured now could be decrypted later, a scenario often called "harvest now, decrypt later".
NIST approved its first three post-quantum standards in August 2024: FIPS 203 (ML-KEM, for key establishment), FIPS 204 (ML-DSA, for digital signatures) and FIPS 205 (SLH-DSA, a hash-based signature scheme). A fourth standard based on the FALCON algorithm, FN-DSA, is being developed as FIPS 206. In March 2025, NIST selected HQC, a code-based algorithm, as a backup to ML-KEM, with a final standard expected in 2027. NIST's draft transition roadmap, IR 8547, proposes deprecating quantum-vulnerable algorithms such as RSA and elliptic-curve cryptography after 2030 and disallowing them after 2035.
Practical first steps include building a cryptographic inventory, identifying long-lived sensitive data, asking vendors about their post-quantum roadmaps and favouring "crypto-agile" designs that allow algorithms to be replaced without redesigning systems.
Cryptography runs through many security roles. The CompTIA Security+ certification preparation covers the fundamentals of encryption, PKI and secure protocols. The ISC2 CISSP certification preparation addresses cryptography within security architecture and engineering, and the Microsoft SC-401 certification preparation focuses on applying encryption and information protection in Microsoft 365.
Effective data protection combines sound algorithms, current protocols, disciplined key management and a plan for the post-quantum transition. Start with an inventory of where cryptography is used, remove obsolete algorithms, secure your keys and build the agility you will need as new standards are adopted.