Which utility is commonly used on OS X to encrypt and decrypt data and messages?

The utility commonly used on OS X to encrypt and decrypt data and messages is GPG, or GNU Privacy Guard. GPG is an open-source implementation of the OpenPGP standard and provides a robust way to secure communications and data through encryption and digital signatures. It allows users to encrypt files, emails, and messages to protect their confidentiality, as well as to ensure the integrity and authenticity of the information exchanged.

While PGP (Pretty Good Privacy) is the original suite for encryption, GPG is its free counterpart and is widely adopted among users on various operating systems, including OS X. GPG's versatility and compatibility with existing PGP users make it a popular choice for those looking to secure their sensitive information on Apple devices.

The other utilities mentioned serve different purposes; for example, a VPN (Virtual Private Network) is primarily used for securing internet connections, IPsec (Internet Protocol Security) is a protocol suite for securing internet protocol (IP) communications, and while PGP is relevant, GPG is the specific implementation that is most commonly associated with OS X for these encryption tasks.