Method crypt

thirdparty/pydes/pyDes.py:564–640

Crypt the data in blocks, running it through des_crypt()

(self, data, crypt_type)

	# Data to be encrypted/decrypted
	def crypt(self, data, crypt_type):
		"""Crypt the data in blocks, running it through des_crypt()"""

		# Error check the data
		if not data:
			return ''
		if len(data) % self.block_size != 0:
			if crypt_type == des.DECRYPT: # Decryption must work on 8 byte blocks
				raise ValueError("Invalid data length, data must be a multiple of " + str(self.block_size) + " bytes\n.")
			if not self.getPadding():
				raise ValueError("Invalid data length, data must be a multiple of " + str(self.block_size) + " bytes\n. Try setting the optional padding character")
			else:
				data += (self.block_size - (len(data) % self.block_size)) * self.getPadding()
			# print "Len of data: %f" % (len(data) / self.block_size)

		if self.getMode() == CBC:
			if self.getIV():
				iv = self.__String_to_BitList(self.getIV())
			else:
				raise ValueError("For CBC mode, you must supply the Initial Value (IV) for ciphering")

		# Split the data into blocks, crypting each one seperately
		i = 0
		dict = {}
		result = []
		#cached = 0
		#lines = 0
		while i < len(data):
			# Test code for caching encryption results
			#lines += 1
			#if dict.has_key(data[i:i+8]):
				#print "Cached result for: %s" % data[i:i+8]
			#	cached += 1
			#	result.append(dict[data[i:i+8]])
			#	i += 8
			#	continue

			block = self.__String_to_BitList(data[i:i+8])

			# Xor with IV if using CBC mode
			if self.getMode() == CBC:
				if crypt_type == des.ENCRYPT:
					block = [b ^ v for b, v in zip(block, iv)]
					#j = 0
					#while j < len(block):
					#	block[j] = block[j] ^ iv[j]
					#	j += 1

				processed_block = self.__des_crypt(block, crypt_type)

				if crypt_type == des.DECRYPT:
					processed_block = [b ^ v for b, v in zip(processed_block, iv)]
					#j = 0
					#while j < len(processed_block):
					#	processed_block[j] = processed_block[j] ^ iv[j]
					#	j += 1
					iv = block
				else: