def testApplyAndExtractOnRandomNotile(self):
data = numpy.random.randint(0, high=2, size=1000).astype(numpy.uint32)
inputMask = numpy.random.randint(0, high=2, size=73).astype(numpy.uint8)
encodedData = mask.applyLSB(data, inputMask, "notile")
outputMask = mask.extractLSB(encodedData).astype(numpy.uint8)
outputMask.resize(inputMask.size)
numpy.testing.assert_array_equal(outputMask, inputMask)
def decode(data):
if not pystegcfg.encoding in pystegcfg.encodingopts:
raise ValueError("Encoding [{0}] is invalid. Can only be one of {1}".format(pystegcfg.encoding, pystegcfg.encodingopts))
encMask = mask.extractLSB(data)
encMsg = tb.uint8mask2text(encMask)
# Find the last occurrence of the delimiter
lastPos = encMsg.rfind(pystegcfg.delim)
if lastPos is -1:
raise StegoException.DecodeError("Could not find any message delimiters")
encMsg = encMsg[:lastPos]
# Extract all instances of the encoded message from the encMsg string
encMsgList = encMsg.split(pystegcfg.delim)
# remove any empty array elements
encMsgList = filter(None, encMsgList)
encMsgListCounted = collections.Counter(encMsgList).most_common()
nElem = len(encMsgListCounted)
if(nElem < 1):
raise StegoException.DecodeError("No message to decode")
return encMsgListCounted
def testApplyAndExtractNotile(self):
outputMask = mask.extractLSB(mask.applyLSB(self.data, self.mask, "notile"))
outputMask.resize(self.mask.size)
numpy.testing.assert_array_equal(outputMask, self.mask)
