NETWAAPPLIEDWIRELESSSECURITYEncryption.pptVIP

NETW 05A: APPLIED WIRELESS SECURITY  Encryption By Mohammad Shanehsaz Spring 2005 Objectives Differentiate between the following encryption schemes in terms of efficiency and security RC4 RC5 DES/3DES AES (FIPS 197) RC4 Developed by Ron Rivest of RSA Security Variable length stream cipher Used in WEP, TKIP, MPPE, SSL, TLS and many other security protocols Fast and efficient The RC4 algorithm is capable of key lengths of up to 256 bits, and is typically implemented in 64 bits, 128 bits, and 256 Considered moderately secure RC4 A stream cipher generates what is called a keystream a sequence of bits used as a key The generation of the keystream can be synchronous - independent of the plaintext and ciphertext (most common stream cipher design), or it can be self-synchronizing - depend on the data and its encryption Encryption is accomplished by combining the keystream with the plaintext, usually with bitwise XOR operation RC5 Developed in 1994 by Ron Rivest of RSA security It is a block cipher Developed for use in software It is used in applications such as Citrix Secure ICA (a technology that provides the foundation for turning any client device thin or fat into a very thin client) RC5 has variable block size (32 bits, 64 bits and 128 bits), variable key size (ranges from 0 bits to 2040 bits) and a variable number of rounds (0 to 255) RC5 There are three routines in RC5: key expansion, encryption, and decryption In key-expansion, the user-provided secret key is expanded to fill a key table whose size depends on the number of rounds Key table is used in both encryption decryption The encryption routine consists of three primitive operations: integer addition, bitwise XOR, and variable rotation DES In 1972 NIST (the National Institute of Standard and Technology) decided that a strong algorithm was needed to protect non-classified information and be available to the general public In 1974 IBM submitted the lucifer algorithm to NIST NIST enlisted the help of the