Which of the following is a common characteristic of VPNs?

A common characteristic of Virtual Private Networks (VPNs) is their ability to encrypt data traffic. This encryption is essential as it protects the confidentiality and integrity of data transmitted over the internet or other networks. When a VPN encrypts the data, it ensures that even if the data packets are intercepted, they cannot be read without the proper decryption key. This security measure is particularly important when transmitting sensitive information, such as personal data or corporate information, especially over public Wi-Fi networks where eavesdropping risks are higher.

The other options do not accurately reflect the main functions or characteristics of VPNs. Improving physical network speed is not a primary role of a VPN; in fact, due to the encryption and tunneling techniques used, there may be a slight decrease in speed. Disabling all local device connections is not a standard feature of VPNs; instead, they typically allow local connections while creating a secure tunnel for external communications. Lastly, while VPNs can restrict access in a network security context, they do not inherently restrict remote access protocols, as the primary focus is on securing data transmission rather than limiting access methods.