1 / 6

Hill Cipher

Hill Cipher. Hill Cipher. Takes two or three or more letter combinations to the same size combinations, e.g. “the”  “rqv” Uses simple linear equations An example of a “block” cipher encrypting a block of text at a time Numbered alphabet: a = 0, b = 1, c = 3, etc. (in CAP, use ASCII code).

ciaran-lang
Download Presentation

Hill Cipher

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Hill Cipher

  2. Hill Cipher • Takes two or three or more letter combinations to the same size combinations, e.g. “the”  “rqv” • Uses simple linear equations • An example of a “block” cipher encrypting a block of text at a time • Numbered alphabet: a = 0, b = 1, c = 3, etc.(in CAP, use ASCII code)

  3. Example C1 = 9*p1 + 18*p2 + 10*p3 (mod 26) C2 = 16*p1 + 21*p2 + 1*p3 (mod 26) C3 = 5*p1 + 12*p2 + 23*p3 (mod 26) C1 9 18 10 p1 C2 = 16 21 1 p2 (mod 26) C3 5 12 23 p3

  4. 4 9 18 10 8 14 = 16 21 1 2 (mod 26) 12 5 12 23 0 18 9 18 10 14 21 = 16 21 1 8 (mod 26) 9 5 12 23 19 19 9 18 10 13 12 = 16 21 1 19 (mod 26) 14 5 12 23 3 I can’t do it 8 2 0 13 19 3 14 8 19  EOM TMY SVJ

  5. Hill – key is matrix k11 k12 k13 k21 k22 k23 k31 k32 k33 Generalize to any size, larger blocks Matrix must be invertible

  6. 23 9 18 10 1 9 = 16 21 1 2 (mod 26) 17 5 12 22 3 23 9 18 10 7 9 = 16 21 1 5 (mod 26) 17 5 12 22 0 Hill -- bad matrix bcd  XJR hfa  XJR

More Related