IT Security II - General Cryptography Concepts

In this unit, you become acquainted with the principles of cryptography. The unit opens with the concepts of cryptography, including the description of vocabulary elements associated with general cryptography. An examination of the fundamental methods of cryptography, encryption, and hashing was presented in terms of the types of algorithms and the types of data. Data can be in either block form, where many bytes are present at a time for encryption, or in stream form, where bytes are spaced temporally. Encryption algorithms are either symmetric or asymmetric in nature. The issue of key exchange, a challenge in the case of symmetric encryption, is presented, including methods such as ephemeral Diffie-Hellman exchanges that offer perfect forward secrecy. Newer methods, including elliptic curve and quantum-based cryptography, are also covered. The unit presents the use of hash functions for verification of integrity. The combination of hash functions with asymmetric encryption enables things such as digital signatures and non-repudiation. The unit concludes with such topics as key escrow and stenography.