Lucky Green has been a long-time activist in the Cypherpunks cryptography advocacy movement. He is best known for his role in coordinating the reverse engineering and break of the GSM digital mobile telephony authentication and voice privacy systems, showing that the systems had been deliberately weakened in the interest of facilitating national intelligence collection. Lucky also FedEx'ed, at his own expense, crates of PGP source code books to Europe, becoming the first person to legally export PGP from the United States. Faced with a demonstration of its absurd position that it was legal to export books from the U.S., but not electronic copies of the source code contained within those books, the U.S. Government came under increasing pressure from industry and was forced to relax governmental controls on strong cryptography in January of 2000.