Related Concepts
Encryption; Symmetric Cryptosystem
This is digraphic, bipartite substitution (Substitutions and Permutations) \({V }_{25} \times {V }_{25} \rightarrow {V }_{25} \times {V }_{25}\), using a 5 × 5 Polybios square and a “crossing step” \((\alpha \beta )(\gamma \delta )\mapsto (\alpha \delta )(\gamma \beta )\). In the example given below, the key palmerstone has been used to make the Polybios square (see mixed, Alphabet).
If a bigram is found in the same row (or the same column), the “crossing step” degenerates: it takes the cyclically right neighbor: am ↦ le; ae ↦ lp; aa ↦ ll (or the neighbor cyclically below: dl ↦ kt; dx ↦ kl). Modified rules are common, especially the one concerning the doubles: perhaps one letter of the pair will be omitted or replaced with a null; in cases like “less seven” this will lead to encrypt “le s& s& se ve n&,” where & is a null.
A modified Playfair uses two Polybios squares, one for the first and one for the second character of the bigrams,...
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsRecommended Reading
Bauer FL (1997) Decrypted secrets. In: Methods and maxims of cryptology. Springer, Berlin
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2011 Springer Science+Business Media, LLC
About this entry
Cite this entry
Bauer, F.L. (2011). Playfair Cipher. In: van Tilborg, H.C.A., Jajodia, S. (eds) Encyclopedia of Cryptography and Security. Springer, Boston, MA. https://doi.org/10.1007/978-1-4419-5906-5_172
Download citation
DOI: https://doi.org/10.1007/978-1-4419-5906-5_172
Publisher Name: Springer, Boston, MA
Print ISBN: 978-1-4419-5905-8
Online ISBN: 978-1-4419-5906-5
eBook Packages: Computer ScienceReference Module Computer Science and Engineering