Created
July 27, 2015 12:43
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| class Crypto | |
| attr_reader :key, :length, :output | |
| AZ_INT_MAPPINGS = {"a"=>1, "b"=>2, "c"=>3, "d"=>4, "e"=>5, "f"=>6, "g"=>7, "h"=>8, "i"=>9, "j"=>10, "k"=>11, "l"=>12, "m"=>13, "n"=>14, "o"=>15, "p"=>16, "q"=>17, "r"=>18, "s"=>19, "t"=>20, "u"=>21, "v"=>22, "w"=>23, "x"=>24, "y"=>25, "z"=>26} | |
| def initialize(count) | |
| @length = count | |
| @key = generate_key | |
| end | |
| def encrypt(input) | |
| input = sanitize(input) | |
| result = "" | |
| (0..(input.length - 1)).each do |index| | |
| c = input[index] | |
| factor = key[index] | |
| next unless factor | |
| sum = to_int(c) + to_int(factor) | |
| sum -= 26 if (sum > 26) | |
| result << to_c(sum) | |
| end | |
| @output = result | |
| end | |
| def decrypt(encrypted) | |
| result = "" | |
| current = 0 | |
| (0..(encrypted.length - 1)).each do |index| | |
| factor = key[index] | |
| c = encrypted[index] | |
| sum = to_int(c) - to_int(factor) | |
| sum += 26 if (sum < 1) | |
| result << to_c(sum) | |
| end | |
| result | |
| end | |
| private | |
| def sanitize(i) | |
| i.downcase.split("").to_a.select{ |i| characters.include?(i) }.join("") | |
| end | |
| def to_int(c) | |
| AZ_INT_MAPPINGS[c] | |
| end | |
| def to_c(i) | |
| int_az_mappings[i] | |
| end | |
| def int_az_mappings | |
| AZ_INT_MAPPINGS.invert | |
| end | |
| def characters | |
| ("a".."z").to_a | |
| end | |
| def generate_key | |
| result = [] | |
| (0..length).each do |c| | |
| result << int_az_mappings[rand(26) + 1] | |
| end | |
| result | |
| end | |
| end |
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