Vigènere in Ruby

vigenere.rb

##~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~##
##            Sirius Fucking Licence 1.2 "ShitStorm"               ##
##           Do the fuck you want. Get the fuck off.               ##
##    Using this licence don't make you more trasgressive.         ##
##           And doesn't mean you're not an asshole.               ##
##~~~~~~~~~~~~~~~*The quiet after the shitstorm*~~~~~~~~~~~~~~~~~~~##
##                   Sirius Fucking Manifesto                      ##
## With this software pubblication licence you can modify, rewrite ##
## rape, burn, kill, delete, fuck, do nothing. In few words:       ##
##        DO DAFUQ YOU WANT AND DON'T EXCORIATE MY BALLS           ##
##~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~##

module Vigenere

	# The length of the clear text, cipher text and worm must be equals!
	# For more information read http://en.wikipedia.org/wiki/Vigenère_cipher
	@alphabeth = [*(?A..?Z)]
	@numbers   = [*(0..@alphabeth.length)]
	@matrix    = Hash[ @alphabeth.zip(@numbers) ]

	# Ci = (Mi + Ki) mod 26
	def self.encode(text, worm)
		vigenere = ''
		i = 0
		text.each_char { |c|
			pos = @matrix[c]
			pos_worm = @matrix[worm[i]]
			sum = (pos + pos_worm) % 26
			vigenere << ((sum > @alphabeth.length) ? @alphabeth.first : @matrix.key(sum))
			i += 1
		}
		vigenere
	end

	# Mi = (Ci - Ki) mod 26
	def self.decode(vigenere, worm)
		text = ''
		i = 0
		vigenere.each_char { |c|
			pos = @matrix[c]
			pos_worm = @matrix[worm[i]]
			sum = (pos - pos_worm) % 26
			text << ((sum > @alphabeth.length) ? @alphabeth.first : @matrix.key(sum))
			i += 1
		}
		text
	end
	
end

puts Vigenere::encode 'ATTACKATDAWN', 'LEMONLEMONLE'
puts Vigenere::decode 'LXFOPVEFRNHR', 'LEMONLEMONLE'