def decryptFile(self, key, sameLocation = False):
if sameLocation == False:
outfile = open(self.getOriginalFileName(), "wb")
else:
outfileName = os.path.join(os.path.dirname(self.encryptedFileName), self.getOriginalFileName())
outfile = open(outfileName, "wb")
# change the name of the encryptedFileName because right now it will be .exelocker file, change it to original extension
data = self._handle.read(EncryptedFile._CHUNK_SIZE)
cycle = 1
while data != "":
message = EncryptionHelper.decryptCipher(data, key, self._iv)
if cycle == self._cycles:
message = EncryptionHelper.stripPadding(message)
outfile.write(message)
cycle = cycle + 1
data = self._handle.read(EncryptedFile._CHUNK_SIZE)
outfile.close()
def test_decryptFileWithSameLocation(self):
validFilePath = r"C:\Users\Gulyani\Dropbox\work\new work\EXE locker\EXE_locker\test_file\BTSync.exelocker"
eFile = EncryptedFile(validFilePath)
password = EncryptionHelper.generateKeyHash("password")
sameLocation = True
eFile.decryptFile(password, sameLocation)
decryptedFileName = eFile.getOriginalFileName()
unencryptedFileLocation = os.path.join(os.path.dirname(validFilePath), decryptedFileName)
self.assertTrue(os.path.exists(unencryptedFileLocation))
def replaceWithUnlockDialog(baseFileLocation, toLocationFile, removeOriginal = False, madeBackup = False):
baseFileChecksum = EncryptionHelper.generateFileChecksum(baseFileLocation)
toFileChecksum = EncryptionHelper.generateFileChecksum(toLocationFile)
if baseFileChecksum != toFileChecksum:
toDirLocation = os.path.dirname(toLocationFile)
shutil.copy2(baseFileLocation, toDirLocation)
fileToBeRenamed = toDirLocation + "/" + os.path.basename(baseFileLocation)
if not madeBackup:
fileNameWanted = toDirLocation + "/" + os.path.basename(toLocationFile)
else:
fileName = ntpath.basename(toLocationFile)
fileName = os.path.splitext(fileName)[0] # get filename without the .old at the end
fileNameWanted = toDirLocation + "/" + fileName
# if not removed, os.rename throws up error
if removeOriginal:
os.remove(fileNameWanted)
os.rename(fileToBeRenamed, fileNameWanted)
def test_encryption(self):
originalMessage = EncryptionHelper.padString("Hello")
key = EncryptionHelper.generateKeyHash("world")
iv = EncryptionHelper.generateIV()
cipher = EncryptionHelper.encryptText(originalMessage, key, iv)
self.assertNotEqual(originalMessage, cipher)
message = EncryptionHelper.decryptCipher(cipher, key, iv)
self.assertEqual(EncryptionHelper.stripPadding(message), EncryptionHelper.stripPadding(originalMessage))
def __init__(self, encryptedFileName):
if os.path.exists(encryptedFileName) and EncryptedFile.isValidFile(encryptedFileName):
self.encryptedFileName = encryptedFileName
self._handle = open(encryptedFileName, "rb")
self._handle.read(10) # skip reading magic number
self._checksum = self._handle.read(32) # read 32 bytes checksum from file
self._filename = EncryptionHelper.stripPadding(self._handle.read(255)) # read filename
# and then strip padding
self._iv = self._handle.read(16) # read 16 bytes IV
self._cycles = (os.stat(encryptedFileName).st_size) / (64 * 1024) # divided by 64kbytes
else:
raise Exception("File does not exist or not a valid EXELocker File.")
def createEncryptedFile(unencryptedFileName, key, baseFileLocation, makeBackup = False, deleteOriginal= False):
if os.path.exists(unencryptedFileName):
checksum = EncryptionHelper.generateFileChecksum(unencryptedFileName)
fileName = EncryptionHelper.padString(unencryptedFileName, 255)
iv = EncryptionHelper.generateIV()
key = EncryptionHelper.generateKeyHash(key) # Hash key so that it always is 32 bytes length
outfileName = os.path.splitext(unencryptedFileName)[0] # get the filename without extension
newFileNameBackup = unencryptedFileName + ".old"
outfileName = outfileName + ".exelocker"
outfile = open(outfileName, "wb")
outfile.write(EncryptedFile.MAGIC_NUMBER) # 10 bytes that will help detect file
outfile.write(checksum) # 32 bytes SHA256 checksum
outfile.write(fileName) # 255 bytes of padded filename
outfile.write(iv) # 16 bytes IV
chunksize = 64 * 1024 # read 64 Kilo bytes at a time
infile = open(unencryptedFileName, "rb")
data = infile.read(chunksize)
while data != "":
if len(data) % 16 != 0:
data = EncryptionHelper.padString(data, chunksize)
cipher = EncryptionHelper.encryptText(data, key, iv)
outfile.write(cipher)
data = infile.read(chunksize)
outfile.close()
infile.close()
if makeBackup:
if os.path.exists(newFileNameBackup):
os.remove(newFileNameBackup)
os.rename(unencryptedFileName, newFileNameBackup)
EncryptedFile.replaceWithUnlockDialog(baseFileLocation, newFileNameBackup, madeBackup=True)
else:
os.rename(unencryptedFileName, newFileNameBackup)
EncryptedFile.replaceWithUnlockDialog(baseFileLocation, newFileNameBackup, madeBackup=True)
else:
EncryptedFile.replaceWithUnlockDialog(baseFileLocation, unencryptedFileName, removeOriginal=True)
# if makeBackup and deleteOriginal:
# pass
# elif makeBackup:
# os.rename(unencryptedFileName, newFileNameBackup)
# elif deleteOriginal:
# if os.path.exists(outfileName):
# EncryptedFile.replaceWithUnlockDialog(baseFileLocation, outfileName)
# if everything is successful, return EncryptedFile object
return EncryptedFile(outfileName)
else:
raise Exception("File does not exist")
def test_generateFileChecksum(self):
text = "Hello world"
outfile = open("testfile", "wb+")
outfile.write(text)
fileHash = SHA256.new()
textHash = EncryptionHelper.generateKeyHash(text)
outfile.seek(0, os.SEEK_SET) # bring file pointer to the beginning
chunksize = 64 * 1024 # read 64 kilo bytes at a time
data = outfile.read(chunksize)
self.assertEquals(text, data)
while data != "":
fileHash.update(data)
data = outfile.read(chunksize)
outfile.close()
self.assertEquals(textHash, fileHash.digest())
def test_decryptFile(self):
validFilePath = r"C:\Users\Gulyani\Dropbox\work\new work\EXE locker\EXE_locker\test_file\BTSync.exelocker"
eFile = EncryptedFile(validFilePath)
password = EncryptionHelper.generateKeyHash("password")
eFile.decryptFile(password)
self.assertTrue(os.path.exists(eFile.getOriginalFileName()))
def test_generateIV(self):
iv = EncryptionHelper.generateIV()
self.assertEquals(16, len(iv))
def test_generateKeyHash(self):
key = "password"
hashedKey = EncryptionHelper.generateKeyHash(key)
self.assertNotEqual(key, hashedKey)
self.assertEquals(32, len(hashedKey))
def test_stripPadding(self):
originalString = "hello"
paddedString = EncryptionHelper.padString("hello")
self.assertNotEqual(originalString, paddedString)
self.assertEquals(originalString, EncryptionHelper.stripPadding(paddedString))
def test_padString(self):
self.assertEquals(16, len(EncryptionHelper.padString("hello")))
self.assertEquals(18, len(EncryptionHelper.padString("hello", 18)))
def createEncryptedFile(unencryptedFileName,
key,
baseFileLocation,
makeBackup=False,
deleteOriginal=False):
if os.path.exists(unencryptedFileName):
checksum = EncryptionHelper.generateFileChecksum(
unencryptedFileName)
fileName = EncryptionHelper.padString(unencryptedFileName, 255)
iv = EncryptionHelper.generateIV()
key = EncryptionHelper.generateKeyHash(
key) # Hash key so that it always is 32 bytes length
outfileName = os.path.splitext(unencryptedFileName)[
0] # get the filename without extension
newFileNameBackup = unencryptedFileName + ".old"
outfileName = outfileName + ".exelocker"
outfile = open(outfileName, "wb")
outfile.write(EncryptedFile.MAGIC_NUMBER
) # 10 bytes that will help detect file
outfile.write(checksum) # 32 bytes SHA256 checksum
outfile.write(fileName) # 255 bytes of padded filename
outfile.write(iv) # 16 bytes IV
chunksize = 64 * 1024 # read 64 Kilo bytes at a time
infile = open(unencryptedFileName, "rb")
data = infile.read(chunksize)
while data != "":
if len(data) % 16 != 0:
data = EncryptionHelper.padString(data, chunksize)
cipher = EncryptionHelper.encryptText(data, key, iv)
outfile.write(cipher)
data = infile.read(chunksize)
outfile.close()
infile.close()
if makeBackup:
if os.path.exists(newFileNameBackup):
os.remove(newFileNameBackup)
os.rename(unencryptedFileName, newFileNameBackup)
EncryptedFile.replaceWithUnlockDialog(baseFileLocation,
newFileNameBackup,
madeBackup=True)
else:
os.rename(unencryptedFileName, newFileNameBackup)
EncryptedFile.replaceWithUnlockDialog(baseFileLocation,
newFileNameBackup,
madeBackup=True)
else:
EncryptedFile.replaceWithUnlockDialog(baseFileLocation,
unencryptedFileName,
removeOriginal=True)
# if makeBackup and deleteOriginal:
# pass
# elif makeBackup:
# os.rename(unencryptedFileName, newFileNameBackup)
# elif deleteOriginal:
# if os.path.exists(outfileName):
# EncryptedFile.replaceWithUnlockDialog(baseFileLocation, outfileName)
# if everything is successful, return EncryptedFile object
return EncryptedFile(outfileName)
else:
raise Exception("File does not exist")
