Skip to main content
placeholder image

Key scheduling in des type cryptosystems

Chapter


Abstract


  • This paper reviews some possible design criteria for the key schedule in a DES style cryptosystem. The key schedule involves a Key Rotation component, and the permutation PC2. Together these provide for a diffusion of dependency of ciphertext bits on key bits. Some empirical rules which seem to account for the derivation of the key schedule used in the DES are first presented. A number of trials were run with various key schedules, and some further design rules were derived. An alternative form of key schedule was then tested. This used either a null PC2, or one in which permutations only occurred within the inputs to a given S-box, and a much larger rotation schedule than used in the DES. This was found to be as effective as the key schedule used in the current DES, and is proposed for use in new cryptosystems.

Publication Date


  • 1990

Citation


  • Brown, L., & Seberry, J. (1990). Key scheduling in des type cryptosystems. In Unknown Book (Vol. 453 LNCS, pp. 221-228). doi:10.1007/BFb0030363

International Standard Book Number (isbn) 13


  • 9783540530008

Scopus Eid


  • 2-s2.0-85028822846

Web Of Science Accession Number


Book Title


  • Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

Start Page


  • 221

End Page


  • 228

Abstract


  • This paper reviews some possible design criteria for the key schedule in a DES style cryptosystem. The key schedule involves a Key Rotation component, and the permutation PC2. Together these provide for a diffusion of dependency of ciphertext bits on key bits. Some empirical rules which seem to account for the derivation of the key schedule used in the DES are first presented. A number of trials were run with various key schedules, and some further design rules were derived. An alternative form of key schedule was then tested. This used either a null PC2, or one in which permutations only occurred within the inputs to a given S-box, and a much larger rotation schedule than used in the DES. This was found to be as effective as the key schedule used in the current DES, and is proposed for use in new cryptosystems.

Publication Date


  • 1990

Citation


  • Brown, L., & Seberry, J. (1990). Key scheduling in des type cryptosystems. In Unknown Book (Vol. 453 LNCS, pp. 221-228). doi:10.1007/BFb0030363

International Standard Book Number (isbn) 13


  • 9783540530008

Scopus Eid


  • 2-s2.0-85028822846

Web Of Science Accession Number


Book Title


  • Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

Start Page


  • 221

End Page


  • 228