ITM 207 Chapter Notes - Chapter 2: Symmetric-Key Algorithm, Public-Key Cryptography, Ciphertext

• School: Ryerson University
• Department: Information Technology Management
• Course: ITM 207
• Professor: farid

Document Summary

Itm 820- chapter 2 [computer security and technology principles] The exact substitutions and transformations performed by the algorithm depend on the key: ciphertext: this is the scrambled message produced as output. It depends on the plaintext and the secret key. For a given message, two different keys will produce two different ciphertext: decryption algorithm: this is essentially the encryption algorithm run in reverse. It takes the ciphertext and the secret key and produces the original plaintext. Symmetric block encryption algorithms: block ciphers, most commonly used symmetric encryption algorithm where it processes the plaintext input in fixed-size blocks and produces a block of ciphertext of equal size for each plaintext box. Modes of operation: to increase the security of symmetric block encryption for large sequences of data, a number of alternative techniques have been developed, they overcome the weakness of ecb.