Translators

Translators take care of translating to and from a specific cipher. There are some (over 10) already included in pycrypt.

Basic usage

Let’s take a look at decoding a Caesar cipher with alphabet shift of 1:

import pycrypt as pc

t = pc.CaesarTranslator()
t.setKey(1)
print t.translate("GDKKN VNQKC!")

Which should output:

HELLO WORLD!

We have created a Translator, set its key (alphabet shift) to 1 and called the method translate to uncover the secret message.

Note

Since Translators are meant to be used on encrypted text, here the method translate actually shifted the alphabet by 1 back, not forward. You can also use the method decode, which is just an alias for translate and is maybe more semantically correct.

We can also revert the process with encode:

>>> t.encode("Hello World!")
'GDKKN VNQKC!'

And that’s about it! But there are some more advanced uses too.

Some translators come with the graphicEncode method, which returns typically a 2d bool NumPy array that we can then draw with pycrypt’s plot_array function:

t = pc.MorseCodeTranslator()
pc.plot_array(t.graphicEncode("SI\nRN\nSI\nNU\nWN\nSI"))

This will draw an image in a new window:

SI RN SI NU WN SI

In this example, MorseCodeTranslator‘s graphicEncode splits the input in lines and concatenates the Morse code characters, that represent the 1s and 0s (black and white squares). You can alter the functionality with some optional arguments.

You can also play around with the interactiveTranslate method, which just cyclically takes standard input, so you could see intermediate results.

And that’s about all the functionality you can expect from Translators. Easy enough, isn’t it?

Making your own Translator

Before we will extend the Translator interface, we should see its methods from the API:

translator Module

class pycrypt.translators.translator.Translator

Abstract class for translating standard ciphers (i.e. Morse Code)

key = []

translate(*args)

Base method for decoding a cipher

interactiveTranslate()

For quick translating with each character typed from the user, type ! to remove last characters

encode(*args)

Reversed translation

decode(*args)

Just and alias for translate

graphicEncode(*args)

Return in numpy array for easy plotting

parseInput(cipher)

Standardize input to a list, values preferably integers indexed from 0

setKey(key)

All you have to do when inheriting from Translator is to implement the translate method. Optionally, you can implement encode and maybe even graphicEncode. parseInput is meant to be just an internal method and implementing it is optional, but pycrypt’s standard is to always make the cipher uppercase. For examples, see to source of some implementations.

Further reading

To check out all Translators, see the API:

See also

Translators