What is Encryption? — UK Software Development Guide

4 min readJune 2025ClickMasters Technical TeamReviewed by James Whitmore, CTO
what is encryption

Direct Answer

Encryption is the process of converting data into a coded format (ciphertext) that can only be read by someone who has the decryption key. The two main types are symmetric encryption (same key to encrypt and decrypt — AES-256 is standard for data at rest) and asymmetric encryption (different keys for encryption and decryption — RSA and elliptic curve used in TLS, digital signatures, and public key infrastructure).

Encryption in the UK

UK GDPR Article 32 specifically mentions encryption as an example of an "appropriate technical measure" for data protection. The ICO has referenced the absence of encryption in enforcement actions — including cases where unencrypted laptops were lost containing personal data. UK standard: AES-256 encryption at rest; TLS 1.2 or 1.3 (not older versions) in transit. Cyber Essentials aligns with these requirements. For HealthTech: NHS DSPT requires encryption of all personal data at rest and in transit. For FinTech: FCA expects encryption standards aligned with industry best practice.

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