ITM 820 Final: final exam notes

• School: Ryerson University
• Department: Information Technology Management
• Course: ITM 820
• Professor: Farid Shirazi

Document Summary

The universal technique for providing confidentiality for transmitted or stored data is symmetric encryption. In this section, we introduce the basic concept of symmetric encryption, followed by an overview of the two most important symmetric encryption algorithms: the data encryption standard (des) and the advanced encryption standard (aes). Des and aes are the most popular examples of block encryption algorithms. Symmetric encryption, also referred to as conventional encryption or single-key encryption, was the only type of encryption in use prior to the introduction of public-key encryption in the late 1970s. 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 ciphertexts: decryption algorithm: this is essentially the encryption algorithm run in reverse. It takes the ciphertext and the secret key and produces the original plaintext.