Data Encryption Standard (DES) and Advanced Encryption Standard (AES)

Abstract

Definition: Data conferencing allows participants in a live session to transfer data and to share applications.Information between the users' applications is transmitted over the network, live and in real-time. Data conferencing is one component of teleconferencing; the others are audio conferencing, and video conferencing. For a teleconferencing system that is ITU-T H.323 [1] compliant, the ITU-T T.120 set of standards [2] are recommended for data conferencing and application sharing, providing real-time communication between two or more entities in a conference. Applications specified as part of the T.120 family include application sharing, electronic whiteboarding, file exchange, and chat. Data conferencing is typically an optional capability in multimedia conferences. The shared data is usually transmitted between the users across the network using a reliable network protocol, such as the TCP (Transmission Control Protocol). See: Teleconferencing DATA DISCOVERY, ROUTING AND TRAFFIC PATTERNS Definition:Resource discovery and rendezvous mechanisms are necessary to dynamically locate media servers (e.g., the nearest or best servers), data storages, membership servers (for multicast sessions), or peers (e.g., other users) for direct connections.In general, the resource discovery module of CHaMeLeoN can be categorized as either 'location-aware' or "location-free". Location-aware architectures require availability of location information. They typically use geographic or trajectory routing to forward the updates or queries and include geographic rendezvous mechanisms (such as GLS [1], Geographic Hash Table for Data-Centric Storage,"The DES algorithm is designed to encipher and decipher 64-bit blocks of data under control of a 64-bit key, of which 56 bits are randomly generated and used directly by the algorithm. Deciphering must be accomplished by using the same key as for enciphering. The deciphering process is the reverse of the enciphering process. A 64-bit block to be enciphered is subject to an initial permutation to form LQ and RQ (32 bits each, respectively the left and right half of the 64-bit block generated by the initial permutation), then to 16-iteration key-dependent computation, and the final result of the computation (Lj^ and R^^) is subject to a permutation that is the inverse of the initial permutation. The 16 key-dependent computations can be simply defined as [1]: /?"=L,,_,e/(/?"_"/^jwhere n is in the range of 1 to 16; / is the cipher function; L,, and /?,, are 32-bits each and respectively the left and right half of the 64-bit iteration result; and K^^ is the 48-bit sub key generated by the following key schedule function KS [1]: K,^=KS{n,KEY)where KEY is the 56-bit main key.With the advance of computation power, a 56-bit key is no longer considered as secure. Triple DES (3DES) is a straightforward way of enhancing the security of DES. 3DES involves repeating the basic DES algorithm three times, using either two or thee unique keys, for a key size of 112 or 168 bits [1].Both DES and 3DES are no...