Minor documentation updates

[szyfrow.git] / szyfrow / caesar.py

diff --git a/szyfrow/caesar.py b/szyfrow/caesar.py
index ec878fcf2fe941d029853d0bed103e9250925054..910ada2f456639160adad6ec4cbf3ad4e08ae567 100644 (file)
--- a/szyfrow/caesar.py
+++ b/szyfrow/caesar.py
@@ -1,10 +1,20 @@
-from support.utilities import *
-from support.language_models import *
+"""Enciphering and deciphering using the [Caesar cipher](https://en.wikipedia.org/wiki/Caesar_cipher). 
+Also attempts to break messages that use a Caesar cipher.
 
-from logger import logger
+The Caesar cipher operates one letter at a time. It converts each letter to a 
+number, then enciphers that number by adding the key. The result is taken mod 
+26 and converted back into a letter.
+
+"""
+
+from szyfrow.support.utilities import *
+from szyfrow.support.language_models import *
 
 def caesar_encipher_letter(accented_letter, shift):
-    """Encipher a letter, given a shift amount
+    """Encipher a letter, given a shift amount.
+
+    Accented version of latin letters (such as é and ö) are converted to their
+    non-accented versions before encryption.
 
     >>> caesar_encipher_letter('a', 1)
     'b'
@@ -93,6 +103,9 @@ def caesar_decipher(message, shift):
 def caesar_break(message, fitness=Pletters):
     """Breaks a Caesar cipher using frequency analysis
 
+    It tries all possible keys, scores the fitness of the text decipherd with 
+    each key, and returns the key that produces the most fit deciphered text.
+
     >>> caesar_break('ibxcsyorsaqcheyklxivoexlevmrimwxsfiqevvmihrsasrxliwyrh' \
           'ecjsppsamrkwleppfmergefifvmhixscsymjcsyqeoixlm') # doctest: +ELLIPSIS
     (4, -130.849989015...)
@@ -109,13 +122,9 @@ def caesar_break(message, fitness=Pletters):
     for shift in range(26):
         plaintext = caesar_decipher(sanitised_message, shift)
         fit = fitness(plaintext)
-        logger.debug('Caesar break attempt using key {0} gives fit of {1} '
-                     'and decrypt starting: {2}'.format(shift, fit,
-                                                        plaintext[:50]))
+
         if fit > best_fit:
             best_fit = fit
             best_shift = shift
-    logger.info('Caesar break best fit: key {0} gives fit of {1} and '
-                'decrypt starting: {2}'.format(best_shift, best_fit, 
-                    caesar_decipher(sanitised_message, best_shift)[:50]))
+
     return best_shift, best_fit