105 lines
2.7 KiB
Ruby
105 lines
2.7 KiB
Ruby
require 'twik/version'
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require 'twik/exceptions'
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require 'openssl'
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require 'base64'
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class Twik
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TYPE = %i{alphanumeric_and_special_chars alphanumeric numeric}
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attr_accessor :privatekey, :length, :type
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def initialize(privatekey, length: 16, type: :alphanumeric_and_special_chars)
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raise UnknownType.new("type should be one of (#{TYPE.join(', ')})") unless TYPE.include?(type)
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raise InvalidLength.new("length should be between 4 and 26") unless (4..26).include?(length)
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self.privatekey = privatekey
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self.length = length
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self.type = type
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end
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def generate(tag, masterkey, length: self.length, type: self.type)
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tag = hash(privatekey, tag, 24) unless privatekey.nil?
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hash(tag, masterkey, length, type)
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end
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private
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def hash(data, key, length, type = :alphanumeric_and_special_chars)
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digest = OpenSSL::Digest.new('sha1')
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data_hash = Base64.strict_encode64(
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OpenSSL::HMAC.digest(digest, key, data)).sub(/=*\z/, '')
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sum = data_hash.chars.map(&:ord).inject(:+)
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if type == :numeric
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data_hash = convert_to_digits(data_hash, sum, length)
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else
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data_hash = inject_character(data_hash, 0, 4, sum, length, '0', 10)
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if type == :alphanumeric_and_special_chars
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data_hash = inject_character(data_hash, 1, 4, sum, length, '!', 15)
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end
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data_hash = inject_character(data_hash, 2, 4, sum, length, 'A', 26)
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data_hash = inject_character(data_hash, 3, 4, sum, length, 'a', 26)
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if type == :alphanumeric
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data_hash = remove_special_characters(data_hash, sum, length)
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end
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end
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data_hash.slice(0, length)
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end
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def convert_to_digits(input, seed, length)
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pivot = 0
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input.chars.map.with_index do |char, i|
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if char =~ /[[:digit:]]/
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res = char
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else
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res = ((seed + input[pivot].ord) % 10 + '0'.ord).chr
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pivot = i + 1
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end
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res
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end.join
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end
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def inject_character(input, offset, reserved, seed, length, c_start, c_num)
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pos0 = seed % length
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pos = (pos0 + offset) % length
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c_start = c_start.ord
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(0..length - reserved).each do |i|
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tmp = (pos0 + reserved + i) % length
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char = input[tmp].ord
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return input if char >= c_start && char < c_start + c_num
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end
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head = input[0..pos-1]
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inject = ((seed + input[pos].ord) % c_num) + c_start
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tail = input[pos+1..-1]
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head + inject.chr + tail
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end
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def remove_special_characters(input, seed, length)
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pivot = 0
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input.chars.map.with_index do |char, i|
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if char =~ /[[:alnum:]]/
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res = char
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else
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res = ((seed + input[pivot].ord) % 26 + 'A'.ord).chr
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pivot = i + 1
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end
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res
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end.join
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end
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end
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