steganography
81Public-key cryptography — In an asymmetric key encryption scheme, anyone can encrypt messages using the public key, but only the holder of the paired private key can decrypt. Security depends on the secrecy of that private key …
82Paradox — For other uses, see Paradox (disambiguation). Further information: List of paradoxes A paradox is a seemingly true statement or group of statements that lead to a contradiction or a situation which seems to defy logic or intuition. Typically,… …
83Polybius — (ca. 203 ndash;120 BC, Greek Polytonic|Πολύβιος) was a Greek historian of the Hellenistic Period noted for his book called The Histories covering in detail the period of 220 ndash;146 BC. He is also renowned for his ideas of political balance in… …
84PCX — may also refer to the Pacific Exchange. PCX Filename extension .pcx Internet media type image/x pcx Developed by ZSoft Corporation Type of format lossless bitmap image format …
85Smoke signal — The smoke signal is one of the oldest forms of communication in recorded history. It is a form of visual communication used over long distance.In Ancient China, soldiers stationed along the Great Wall would alert each other of impending enemy… …
86Security engineering — is a specialized field of engineering that focuses on the security aspects in the design of systems that need to be able to deal robustly with possible sources of disruption, ranging from natural disasters to malicious acts. It is similar to… …
87SANS Institute — The SANS Institute (SysAdmin, Audit, Networking, and Security) is a trade name owned by the for profit Escal Institute of Advanced Technologies. SANS provides computer security training, professional certification, and a research archive. It was… …
88Signals intelligence — SIGINT redirects here. For the UNIX signal, see SIGINT (POSIX). RAF Menwith Hill, a large site in the United Kingdom, part of ECHELON and the UK USA Security Agreement. Signals intelligence (often contracted to SIGINT) is intelligence gathering… …
89DeCSS — A fragment of the DeCSS code, which can be used by a computer to circumvent a DVD s copy protection. DeCSS is a computer program capable of decrypting content on a commercially produced DVD video disc. Before the release of DeCSS, there was no… …
90Substitution cipher — In cryptography, a substitution cipher is a method of encryption by which units of plaintext are replaced with ciphertext according to a regular system; the units may be single letters (the most common), pairs of letters, triplets of letters,… …
