NOBUS, short for "NObody But US", are security vulnerabilities which NSA thinks only NSA can exploit. As such, NSA sometimes chooses to leave such vulnerabilities open if NSA finds them, in order to exploit them against NSA's targets. NSA has a dual mission of both attacking foreign systems and defending US systems, so keeping significant vulnerabilities which affect US systems secret is a conflict of interest. You look at a vulnerability through a different lens if even with the vulnerability it requires substantial computational power or substantial other attributes and you have to make the...

Kleptography is the study of stealing information securely and subliminally. Kleptography is a subfield of cryptography and cryptovirology, and is a natural extension of the theory of subliminal channels that was pioneered by Gus Simmons while at Sandia National Labs. Kleptography is also related to steganography. Kleptography was introduced by Adam Young and Moti Yung in the Proceedings of Advances in Cryptology—Crypto '96. == Kleptographic attack == === Meaning === A kleptographic attack is an attack which uses asymmetric encryption to implement a cryptographic backdoor. For example, ...