Spycraft - Melton [260]
Intelligence services with limited financial resources soon adopted PGP and similar encryption software to create powerful and unbreakable agent covcom systems once available only to the major superpowers. The small, but aggressive, Cuban intelligence service used publicly available encryption software to communicate with its agents operating inside the United States. An advanced version of a PGP encryption program was discovered in September of 2001 during the search of the Washington, D.C. apartment of Ana Belen Montes. Montes, who the FBI code named BLUE WREN, was a Defense Intelligence Agency intelligence analyst for Cuban affairs, and a spy for the Cuban intelligence service.
For her covcom, Montes had been instructed to purchase a Toshiba 405CS laptop computer and was provided by her Cuban handlers, assigned to the Cuban Mission at the United Nations, with two diskettes, S-1 and R-1, for encrypting and decrypting messages. Because the possession of high-level encryption software would be alerting if Montes’s laptop computer was examined forensically, digital encryption programs (PGP or similar) and one-time keys were embedded on each diskette. When receiving messages transmitted to her Sony shortwave radio by her service, she would copy and enter the ciphertext numbers into her laptop computer and insert diskette R-1 to recover the plaintext. To prepare secret information to be handed over to the Cubans she would enter the plaintext into her laptop and then use the encryption program and key embedded on diskette S-1 to convert it into ciphertext.
Diagram of Cuban agent Ana Belen Montes’s one-way voice system for receiving encoded messages from Cuba, 2001.
As long as Montes wiped her laptop hard drive after each covert use (to erase any trace of the process), and concealed her two special diskettes, the messages she was sending and receiving would have been virtually unbreakable. Despite her instructions, Montes did not wipe her hard drive after each use. As a result, during the FBI search of her apartment and computer, plaintext copies of her communications were recovered.20 The weakness was not in the encryption software, but with the faulty tradecraft of Montes.
Once a message is encrypted, digital steganography can be used to hide it among the ones and zeros in any electronic transmission. Steganography, while not a form of encryption, protects messages by rendering them invisible. If the existence of a message cannot be discovered, its secrets are not revealed.
Publicly known digital techniques have made the use of steganography available to anyone to hide data and messages in virtually any electronic document and instantly send the secret information to anywhere on the globe over the Internet. Spies used limited digital techniques for hiding information during the Cold War. In the late 1980s, FBI Special Agent Robert Hanssen, a mole for the KGB, sent messages to his handlers on eight-inch floppy computer diskettes. Because the secrets he was selling would likely lead a trail back to him if discovered, Hanssen first encrypted the information and then concealed it on the diskettes using a technique called “40 track encryption.” The little-known technical process reformatted the computer diskette and allowed data to be concealed by placing it onto specific tracks on the diskette inaccessible to the computer’s internal