At which layer of the OSI model does encryption occur?

Encryption can occur at various layers of the OSI model, depending on the protocols in use. At Layer 3, encryption protocols like IPsec can be used to secure data transmitted over IP networks by encrypting the payload and providing authentication. Layer 7, the application layer, also uses encryption through protocols such as HTTPS, which encrypts HTTP messages to ensure secure communications between web clients and servers.

This means that the application layer can implement encryption applications specific to services, while the network layer can encrypt data at the packet level to protect the data as it traverses a network. Since different applications and protocols might implement encryption at different layers, stating that it can occur at any layer is accurate.

Thus, the answer highlights the flexibility and variety of encryption options available across multiple levels of the OSI model.