Asymmetric encryption (key pair) meaning

Asymmetric encryption (key pair) is a public‑key cryptography method used in legal practice to create and verify electronic or digital signatures, protect document integrity and authenticate the sender. Software generates a mathematically linked key pair: a private key kept secret by the signatory and a public key shared with recipients, typically via a digital certificate issued under a public key infrastructure (PKI). To sign, the private key is used to encrypt a hash of the document; recipients use the public key to verify the signature and detect any alteration of the signed content (non‑repudiation and integrity). The same technique can also be used to encrypt data for confidentiality, with the public key encrypting and the private key decrypting. The term is a technical description rather than a statutory definition, but its use is recognised by the UK eIDAS regime (retained EU Regulation 910/2014) and the EU eIDAS Regulation in Ireland, which reference public‑key methods for advanced and qualified electronic signatures and seals. Usage and legal effect are broadly consistent across England & Wales, Scotland, Northern Ireland and Ireland. Effective key management, certificate validity and control of the private key are critical to evidential reliability and compliance.