GnuPG (GNU Privacy Guard or GPG) is a comprehensive and versatile encryption software, primarily designed for secure communication and data protection. It allows users to encrypt and sign their communications and files, ensuring authenticity and confidentiality. GnuPG adheres to the OpenPGP standard as defined by RFC4880, which enables compatibility with a wide range of other applications and systems. It supports multiple encryption algorithms, including RSA, DSA, and ElGamal.GnuPG is a free and open-source software, available under the GNU General Public License (GPL), making it accessible for both personal and professional use without any licensing fees. It is a foundational tool for cryptographic communication, widely utilized in email security and used as the backend for many other security applications.