Encrypting your confidential messages

If your son starts typing encrypted emails to his friends this is how he might have accomplished this.

letters =    'abcdefghijklmnopqrstuvwxyz '
encryption = 'cfzbwhmpxnaqdosyeikugjtvrl '

message = 'this is the story about udacity challenging the established way of teaching students'
translated = ''.join([encryption [letters.index(letter)] for letter in message])
print translated

A more efficient way is to make a translation table first so we can use string.translate(table) method.

from string import maketrans

letters =    'abcdefghijklmnopqrstuvwxyz '
encryption = 'cfzbwhmpxnaqdosyeikugjtvrl '
 
message = 'this is the story about udacity challenging the established way of teaching students'
translationtable = maketrans(letters, encryption)
translated = message.translate(translationtable)
print translated

upxk xk upw kusir cfsgu gbczxur zpcqqwomxom upw wkucfqxkpwb tcr sh uwczpxom kugbwouk

What will be more challenging is to de-encrypt his message as you evidently don't know the encryption used. Interesting topic for a next article ;-)

Just as a side note: Any clue how many permutations exist for 27 characters??
27! = 1.08888695 × 1028