Class: Analyzers::VigenereXor

Inherits:
Object
  • Object
show all
Includes:
Utils::Reporting::Console
Defined in:
lib/crypto-toolbox/analyzers/vigenere_xor.rb

Defined Under Namespace

Classes: EightBitPatternFinder, HammingDistanceKeyLengthFinder, StaticKeylength

Instance Method Summary collapse

Methods included from Utils::Reporting::Console

#jot, #print_delimiter_line, #print_nice, #print_raw

Instance Method Details

#analyse_single(buf, key_length) ⇒ Object 



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# File 'lib/crypto-toolbox/analyzers/vigenere_xor.rb', line 99

def analyse_single(buf,key_length)
  candidate_map = Analyzers::Utils::KeyCandidateMap.create(buf,key_length)

 
  candidate_amount = candidate_map.map{|k,v| v.length}.reduce(&:*)
  if candidate_amount.zero?
    jot("no combinations for keylen #{key_length} (at least one byte has no candidates)",debug: true)
    return []
  end
  jot "Amount of candidate keys: #{candidate_map.map{|k,v| v.length}.reduce(&:*)}. Starting Permutation (RAM intensive)",debug: true

  
  # split the candidate map into head and*tail to create the prduct of all combinations
  head,*tail = candidate_map.map{|k,v|v}
  begin
    combinations = head.product(*tail) 
    # we simply skip too big products
  rescue RangeError => ex
    jot "keylen: #{key_length}: #{ex}"
    return []
  end


  
  if ENV["DEBUG_ANALYSIS"]
    ensure_consistent_result!(combinations,candidate_map)
    print_candidate_decryptions(candidate_map,key_length,buf)
  end

  
  keys = Analyzers::Utils::KeyFilter::AsciiPlain.new(combinations,buf).filter.reject(&:empty?)

  # return the result, not the key
  keys.map do|key|
    key.xor(buf)
  end
end

#analyze(input, keylength_strategy = EightBitPatternFinder.new) ⇒ Object 



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# File 'lib/crypto-toolbox/analyzers/vigenere_xor.rb', line 89

def analyze(input, keylength_strategy=EightBitPatternFinder.new)
  buf = CryptBuffer.from_hex(input)

  keylength_strategy.keylen_for(buf).map do |keylen|
    analyse_single(buf,keylen)
  end.flatten
end