Using Algorithms
Bruce Schneier · 2015
This chapter first discusses how to choose among public algorithms that have withstood a reasonable amount of public scrutiny and cryptanalysis. Then, it compares public-key algorithms than with symmetric algorithms. Symmetric cryptography is best for encrypting data. It is orders of magnitude faster and is not susceptible to chosen-ciphertext attacks. Public-key cryptography can do things that symmetric cryptography can't; it is best for key management and a myriad of protocols. In theory, an encryption can take place at any layer in the Open Systems Interconnect (OSI) communications model. The chapter explains and compares link-by-link encryption and end-to-end encryption. More companies are starting to put encryption hardware into their communications equipment. Internal key management for these devices is generally secure, although there are as many different schemes as there are equipment vendors.