Module: ZSteg::Checker::SteganographyPNG

Defined in:
lib/zsteg/checker/steganography_png.rb

Defined Under Namespace

Classes: Result

Constant Summary collapse

URL = 
"https://github.com/pedrooaugusto/steganography-png"

Class Method Summary collapse

Class Method Details

.check_image(image, _params = {}) ⇒ Object 



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# File 'lib/zsteg/checker/steganography_png.rb', line 24

def self.check_image image, _params = {}
  ls = image.scanlines.last
  data = ls.decoded_bytes
  secret_type_length = data[-1].ord
  return nil if secret_type_length > data.size - 8
  data = data[ -secret_type_length-8 .. -2 ]
  # data.size to prevent "want 8 bytes, got 7" IOStruct warning when secret_type_length == 0
  r = Result.read(data, data.size)
  r.valid? && [r, URL]
end