Class: CryptoToolchain::Tools::InteractiveXor

Inherits:
Object
  • Object
show all
Defined in:
lib/crypto_toolchain/tools/interactive_xor.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(ciphertexts) ⇒ InteractiveXor

Returns a new instance of InteractiveXor.



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# File 'lib/crypto_toolchain/tools/interactive_xor.rb', line 13

def initialize(ciphertexts)
  @ciphertexts = ciphertexts
end

Instance Attribute Details

#ciphertexts ⇒ Object (readonly)

Returns the value of attribute ciphertexts.



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# File 'lib/crypto_toolchain/tools/interactive_xor.rb', line 12

def ciphertexts
  @ciphertexts
end

Instance Method Details

#attempt(index, *plains) ⇒ Object

index is the index of the ciphertext against which you are making an attempt Plains are the plaintexts you want to try as possibilities



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# File 'lib/crypto_toolchain/tools/interactive_xor.rb', line 37

def attempt(index, *plains)
  validate_length!(plains)
  keys = keys_for(plains, index)
  ciphertexts.each_with_index do |ct, i|
    line = keys.map do |k|
      _len = [ct.bytesize, k.bytesize].min
      ct[0..._len] ^ k[0..._len]
    end.join("     |     ")
    puts "#{i}\t#{line}"
  end
  nil
end

#execute ⇒ Object 



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# File 'lib/crypto_toolchain/tools/interactive_xor.rb', line 17

def execute
  binding.pry
end

#keys_for(plains, index) ⇒ Object 



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# File 'lib/crypto_toolchain/tools/interactive_xor.rb', line 28

def keys_for(plains, index)
  plains.map.with_index do |pl|
    len = [pl.length, ciphertexts[index].length].min
    ciphertexts[index][0...len] ^ pl[0...len]
  end
end

#validate_length!(plains) ⇒ Object 



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# File 'lib/crypto_toolchain/tools/interactive_xor.rb', line 21

def validate_length!(plains)
  len = plains.first.length
  plains.each do |pl|
    raise ArgumentError.new("must have same length") unless pl.length == len
  end
end