Encryption
symmetric encryption · asymmetric encryption · cipher · AES · RSA · end-to-end encryption · chiffrement
A process that makes data unreadable to anyone who does not hold the right key, to protect its confidentiality while it is stored or transmitted.
In practice
Symmetric encryption (AES, for example) uses the same key to encrypt and decrypt: it is fast and protects disks, backups and databases. Asymmetric encryption (RSA, elliptic curves) relies on a key pair, one public and one private; it is mainly used to exchange a secret key or to sign, as in TLS. Strength depends less on the algorithm, which is solid if it is a standard one, than on key management: where are the keys stored, who can reach them, how are they renewed? The GDPR (Article 32) explicitly lists encryption among appropriate security measures.
Fictional case: a salesperson’s laptop, full of customer files, is stolen on a train. Its disk is encrypted and the key is protected by the TPM chip and a PIN: the data is useless to the thief, and the company can prove it.
How to protect yourself
- Encrypt the disks of company laptops and phones.
- Encrypt backups and keep their keys somewhere other than next to the backups.
- Use standard algorithms only, never home-made encryption.
- Manage keys in a vault or an HSM, with logged access and rotation.
