A data encryption and decryption computer program that provides cryptographic privacy and authentication for data communication. The program was introduced to secure texts, emails and files. It was invented by Phil Zimmerman in order for people to protect themselves from intrusive governments, businesses and institutions around the world. Zimmerman posted the program on the internet as a free download, however the United States government were concerned over the strength of the program and prosecuted Zimmerman. The charges were later dropped.