1 / 9

Cryptanalysis

Cryptanalysis. codes & ciphers. Simple Substitution. Reciprocal system works both ways A = Z, and Z = A Atbash cipher A is replaced with Z, B with Y, etc. Simple Substitution. Non-reciprocal system the alphabet is written out twice Keyboard cipher QWERTY becomes ABCDEF, etc.

tyanne
Download Presentation

Cryptanalysis

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. Cryptanalysis codes & ciphers

  2. Simple Substitution Reciprocal system works both ways A = Z, and Z = A • Atbash cipher • A is replaced with Z, B with Y, etc.

  3. Simple Substitution Non-reciprocal system the alphabet is written out twice • Keyboard cipher • QWERTY becomes ABCDEF, etc. • recipient labels the buttons on the keyboard so that when the enciphered message is typed, the plaintext is revealed

  4. Simple Substitution • Caesar shift • each letter is shifted a set number of spaces • Variable shift • using a key number

  5. Simple Substitution • Random alphabet table • Key word • key word first • remove repeated letters • the rest of the alphabet follows in sequence

  6. More on Simple Substitution • Orphan Annie cipher • create a non-reciprocal alphabet table, where the top row is A-Z and the bottom row is random • starting with A, create a new sequence of letters (A  J  S  C, etc.) • use the new sequence to form a new alphabet table and perform a Caesar shift • recipient needs a copy of the original table

  7. Pigpen • Original form • Alternate arrangements • Use key word for added complexity

  8. Other Simple Substitution Ciphers Non-reciprocal substitution • Cipher disc • Saint Cyr slide Substitution with symbols • Hieroglyphics • Shadow cipher • Babington code • a nomenclator

  9. Other Simple Substitution Ciphers • Algebraic equation • letters are assigned numeric values, based on their positions in the alphabet • x is the number from the ciphertext • solving for y gives the plaintext value • only positive integers count, others are nulls

More Related