GnuPG Made Easy (GPGME) is a library designed to make access to GnuPG easier for applications. It provides a High-Level Crypto API for encryption, decryption, signing, signature verification and key management. Currently it uses GnuPG as it's backend but the API isn't restricted to this engine; in fact it is planned to add other backends to it.
WWW: https://www.gnupg.org/software/gpgme/index.html