def applyCBC(text, DESKey, initialVector, mode):
# convert all parameters into binary
# text = convertToBinary(text)
# DESKey = convertToBinary(DESKey)
# initialVector = convertToBinary(initialVector)
feedback = initialVector
# divide the text into blocks each of size 64 bits
textIntoParts = splitIntoParts(text, 64)
result = []
for i in range(len(textIntoParts)):
if (mode == ENCRYPT):
res = xor(feedback, textIntoParts[i], 64)
feedback = applyDES(res, DESKey, ENCRYPT)
result.append(feedback)
else:
desres = applyDES(textIntoParts[i], DESKey, DECRYPT)
res = ""
if (i == 0):
res = xor(desres, initialVector, 64)
else:
res = xor(desres, textIntoParts[i - 1], 64)
result.append(res)
# convert the binary back to characters
return ("".join(result))
def CBCEncryptRound(firstHalfFeedback, lastHalfFeedback, firstHalfText,
lastHalfText, iv1, iv2, DESKey1, DESKey2):
# apply des for the two halves of the feedback
firstHalfRes = applyDES(firstHalfFeedback, DESKey1, ENCRYPT)
lastHalfRes = applyDES(lastHalfFeedback, DESKey2, ENCRYPT)
# xor the two des results with a half of the plain text
firstHalfCipher = xor(firstHalfText, firstHalfRes, 64)
lastHalfCipher = xor(lastHalfText, lastHalfRes, 64)
# apply des for the xor'd results
lastCipher = applyDES(firstHalfCipher, DESKey2, ENCRYPT)
firstCipher = applyDES(lastHalfCipher, DESKey1, ENCRYPT)
# xor the result of des with a half of the initial vector
firstCipher = xor(firstCipher, iv1, 64)
lastCipher = xor(lastCipher, iv2, 64)
# return the cipher text
return [firstCipher, lastCipher]
def CBCDecryptRound(firstHalfFeedback, lastHalfFeedback, firstHalfCipher,
lastHalfCipher, iv1, iv2, DESKey1, DESKey2):
# xor the halves of cipher text and initial vector
firstHalfCipher = xor(firstHalfCipher, iv1, 64)
lastHalfCipher = xor(lastHalfCipher, iv2, 64)
# apply des for the two halves of cipher text in decryption mode
firstHalfRes1 = applyDES(firstHalfCipher, DESKey1, DECRYPT)
lastHalfRes1 = applyDES(lastHalfCipher, DESKey2, DECRYPT)
# apply des for the two halves of the feedback in encryption mode
firstHalfRes2 = applyDES(lastHalfFeedback, DESKey1, ENCRYPT)
lastHalfRes2 = applyDES(firstHalfFeedback, DESKey2, ENCRYPT)
# cross xor the halves the two des results
firstHalfText = xor(firstHalfRes2, lastHalfRes1, 64)
lastHalfText = xor(firstHalfRes1, lastHalfRes2, 64)
# return the plain text
return [firstHalfText, lastHalfText]
def applyDESOnAChannel(channel, h, deskey, mode):
# convert the key to binary string
deskey = convertCharToBinary(deskey)
# iterate through row
for i in range(h):
# first split the row values into groups of 8
channelListIntoParts = splitIntoParts(channel[i], 8)
# then iterate through each group
for k in range(len(channelListIntoParts)):
# convert the list into a binary string
pltxt = convertNumToBinary(channelListIntoParts[k])
# apply the DES for the binary string in encryption mode
cipher = applyDES(pltxt, deskey, mode)
# convert the binary string into number list and create a list of type uint8 for the encrypted binary string
cipherList = numpy.array(convertBinaryToNum(cipher),
dtype=numpy.uint8)
# replace the original value with the cipher value
channelListIntoParts[k] = cipherList
# replace the original row value with the new ciphered value
channel[i] = mergeParts(channelListIntoParts)
# return the channel
return channel
def callDES(text, key, index):
r = applyDES(text, key)
res[index] = r
print("-" * 64)
# ---Encryption---
# get the width and height of the image
w, h = img.shape
print("Encrypting...")
# iterate through each row
for i in range(h):
# first split the row values into groups of 8
imgListIntoParts = splitIntoParts(img[i], 8)
# then iterate through each group
for k in range(len(imgListIntoParts)):
# convert the list into a binary string
pltxt = convertNumToBinary(imgListIntoParts[k])
# apply the DES for the binary string in encryption mode
cipher = applyDES(pltxt, deskey, ENCRYPT)
# convert the binary string into number list and create a list of type uint8 for the encrypted binary string
cipherList = numpy.array(convertBinaryToNum(cipher), dtype=numpy.uint8)
# replace the original value with the cipher value
imgListIntoParts[k] = cipherList
# replace the original row value with the new ciphered value
img[i] = mergeParts(imgListIntoParts)
print("Encryption done!")
# show the encrypted image
cv2.imshow("encrypted image", img)
cv2.waitKey(0)
# save the encrypted image to this directory
cv2.imwrite("./encrypted.png", img)
print("Saved the encrypted image into current directory!")
cv2.destroyAllWindows()