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Lecture Data security and encryption - Lecture 9: AES

This chapter presents the following content: The AES selection process; The details of Rijndael – the AES cipher; looked at the steps in each round; out of four AES stages, two are discussed; substitute bytes; shift rows. | Data Security and Encryption (CSE348) Lecture slides by Lawrie Brown for “Cryptography and Network Security”, 5/e, by William Stallings, briefly reviewing the text outline from Ch 0, and then presenting the content from Chapter 1 – “Introduction”. Lecture # 9 Review Data Encryption Standard (DES) Strengths of DES Differential & Linear Cryptanalysis block cipher design principles Chapter 3 summary. DES Encryption Overview The overall scheme for DES encryption is illustrated in Stallings Figure 3.4, which takes as input 64-bits of data and of key. The left side shows the basic process for enciphering a 64-bit data block which consists of: - an initial permutation (IP) which shuffles the 64-bit input block - 16 rounds of a complex key dependent round function involving substitutions & permutations - a final permutation, being the inverse of IP The right side shows the handling of the 56-bit key and consists of: - an initial permutation of the key (PC1) which selects 56-bits out of the 64-bits input, in two 28-bit halves - 16 stages to generate the 48-bit subkeys using a left circular shift and a permutation of the two 28-bit halves DES Encryption Overview The overall scheme for DES encryption is illustrated in Stallings Figure which takes as input 64-bits of data and of key The left side shows the basic process for enciphering a 64-bit data block which consists of: an initial permutation (IP) which shuffles the 64-bit input block 16 rounds of a complex key dependent round function involving substitutions & permutations a final permutation, being the inverse of IP The overall scheme for DES encryption is illustrated in Stallings Figure 3.4, which takes as input 64-bits of data and of key. The left side shows the basic process for enciphering a 64-bit data block which consists of: - an initial permutation (IP) which shuffles the 64-bit input block - 16 rounds of a complex key dependent round function involving substitutions & . | Data Security and Encryption (CSE348) Lecture slides by Lawrie Brown for “Cryptography and Network Security”, 5/e, by William Stallings, briefly reviewing the text outline from Ch 0, and then presenting the content from Chapter 1 – “Introduction”. Lecture # 9 Review Data Encryption Standard (DES) Strengths of DES Differential & Linear Cryptanalysis block cipher design principles Chapter 3 summary. DES Encryption Overview The overall scheme for DES encryption is illustrated in Stallings Figure 3.4, which takes as input 64-bits of data and of key. The left side shows the basic process for enciphering a 64-bit data block which consists of: - an initial permutation (IP) which shuffles the 64-bit input block - 16 rounds of a complex key dependent round function involving substitutions & permutations - a final permutation, being the inverse of IP The right side shows the handling of the 56-bit key and consists of: - an initial permutation of the key (PC1) .