Which of the following is NOT a responsibility of the Application layer in the OSI model?

The Application layer in the OSI model primarily focuses on providing services and interface for network applications. Its main responsibilities include establishing communication and managing user interface processes, as well as enabling access to network services through protocols like HTTP, FTP, and SMTP.

Data formatting, which includes processes such as converting data into a format usable by the application, is also a key responsibility of the Application layer. This ensures that any data sent over the network can be properly interpreted by the receiving application.

While encryption can be a critical part of securing data, it typically falls within the scope of the Presentation layer, which handles data translation, encryption, and compression. Therefore, stating that data encryption is a responsibility of the Application layer is not accurate, making it the correct answer to identify as NOT a responsibility of the Application layer in the OSI model.

Protocol management, while closely related to ensuring communication success for applications, can occur across multiple layers, but the Application layer is indeed involved in managing the protocols that facilitate access to services.