华工密码学老师上课课件ch02 4).pdf

Cryptography and Cryptography and CCrryyppttooggrraapphhyy aanndd Cryptography and Cryptography and CCrryyppttooggrraapphhyy aanndd Network Security Network Security NNeettwwoorrkk SSeeccuurriittyy Network Security Network Security NNeettwwoorrkk SSeeccuurriittyy Chapter 2 Chapter 2 CChhaapptteerr 22 Chapter 2 Chapter 2 CChhaapptteerr 22 Fifth Edition Fifth Edition by William Stallings by William Stallings - Lecture slides by Lawrie Brown - Lecture slides by Lawrie Brown Zhang Jing Zhang Jing Chapter 2 – Classical Encryption Chapter 2 – Classical Encryption CChhaapptteerr 22 –– CCllaassssiiccaall EEnnccrryyppttiioonn Chapter 2 – Classical Encryption Chapter 2 – Classical Encryption CChhaapptteerr 22 –– CCllaassssiiccaall EEnnccrryyppttiioonn Techniques Techniques TTeecchhnniiqquueess Techniques Techniques TTeecchhnniiqquueess Symmetric Encryption Symmetric Encryption SSyymmmmeettrriicc EEnnccrryyppttiioonn Symmetric Encryption Symmetric Encryption SSyymmmmeettrriicc EEnnccrryyppttiioonn � or conventional / private-key / single-key � or conventional / private-key / single-key � sender and recipient share a common key � sender and recipient share a common key � all classical encryption algorithms are � all classical encryption algorithms are private-key private-key � was only type prior to invention of public- � was only ty