Encryption
Definition
Frequently asked questions
What is the difference between symmetric and asymmetric encryption?
Symmetric encryption uses the same key to encrypt and decrypt; it is fast and serves to protect large volumes of data. Asymmetric encryption uses two keys, one public, the other private; slower, it is mainly used to exchange a symmetric key securely. Common protocols combine both.
Encrypting a document, is that signing it?
No, these are two distinct operations. Encryption makes the document unreadable for anyone without the key: it protects confidentiality. A signature leaves the document readable, but proves who approved it and that it has not been modified. A document can be signed without being encrypted, and vice versa.
What do encryption in transit and encryption at rest mean?
Encryption in transit protects data while it circulates over the network, between the browser and the server; this is the role of the TLS protocol. Encryption at rest protects data once stored, on disk or in a database. Both are complementary: the former defeats interception, the latter prevents theft of a storage medium.
Is encryption required by GDPR?
Not absolutely. Article 32 of GDPR cites it as an example of an appropriate security measure that the data controller must implement based on risks. In practice, for contractual documents containing personal data, dispensing with it would be difficult to justify. It also reduces notification obligations in case of a breach.
Associated guides
Related terms
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