def prepareMetadataChunks(metadataTuple, privateHandle):
"""Encrypts, signs and adds the necessary flags to the metadata chunks.
Arguments:
metadataTuple {tuple of {bytes}} -- Output of squashAndSplitMetadataChunk(), where every element of the tuple is a metadata chunk.
privateHandle {bytes} -- Self-explanatory.
Returns:
list -- List of metadata chunks - in order - ready to be encoded into trytes and sent in an iota tx.
"""
encryptionKey = encryption.getEncryptionKey(privateHandle)
signingKey, verifyingKey = encryption.getKeypair(privateHandle)
metadataChunkList = []
address_gen = datamap.createDatamapGenerator(verifyingKey, len(metadataTuple) + 2)
next(address_gen) # first address is the treasure chunk's so we don't need it right now
for i, metadataChunk in enumerate(metadataTuple):
encryptedChunk, nonce, _ = encryption.encryptAES(metadataChunk, encryptionKey)
preparedChunk = encryptedChunk+nonce
address = encryption.trytesToBytes(next(address_gen)[:-1])
if i == 0:
preparedChunk = addMetadataFlags(preparedChunk, len(metadataTuple))
signature = encryption.signChunk(preparedChunk + address, signingKey)
finalMetadataChunk = b"".join([preparedChunk, signature])
metadataChunkList.append(finalMetadataChunk)
return metadataChunkList
def test_End_to_End():
number_of_files = random.randint(4, 10)
filenameList = ["testfile_" + str(i+1) for i in range(number_of_files)]
initialize_multiple_files(filenameList)
passwordFlagList = [bool(random.getrandbits(1)) for i in filenameList]
passwordDict = {filename:"oyster" for filename, flag in zip(filenameList, passwordFlagList) if flag}
privateHandle = encryption.getPrivateHandle()
_, verifyingKey = encryption.getKeypair(privateHandle)
encryptionKey = encryption.getEncryptionKey(privateHandle)
rawMetadataChunk = fileprocessor.makeMetadataChunk(filenameList, passwordFlagList, verifyingKey)
metadataChunkTuple = fileprocessor.squashAndSplitMetadataChunk(rawMetadataChunk)
allChunksList = [b"TreasureChunkHere"] + fileprocessor.prepareMetadataChunks(metadataChunkTuple, privateHandle)
for filename in filenameList:
offsetHash = bytes.fromhex(rawMetadataChunk[filename]["offsetHash"])
if filename in passwordDict: # This statement is only True if filename has been added to the keys in the dict, which means it has a password
fileChunks = fileprocessor.fileToChunks(filename, privateHandle, offsetHash, password=passwordDict[filename])
else:
fileChunks = fileprocessor.fileToChunks(filename, privateHandle, offsetHash)
allChunksList += fileChunks
firstMetadataChunk = allChunksList[1]
metadataChunkNumberFlag_bytes, _ = fileprocessor.stripMetadataFlags(firstMetadataChunk)
numberFlag = int(np.fromstring(metadataChunkNumberFlag_bytes, dtype='uint8'))
metadataArray = allChunksList[1:numberFlag+1]
metadataJSON = fileprocessor.unpackMetadata(metadataArray, encryptionKey)
decrypted_filenameList = list(metadataJSON.keys())
for filename in decrypted_filenameList:
startIdx = metadataJSON[filename]["startIdx"]
endIdx = startIdx + metadataJSON[filename]["chunkCount"]
passwordFlag = bool(metadataJSON[filename]["password"])
decrypted_filename = "decrypted_"+filename
fileList = allChunksList[startIdx:endIdx]
if passwordFlag:
fileprocessor.chunksToFile(fileList, encryptionKey, decrypted_filename, password=passwordDict[filename])
else:
fileprocessor.chunksToFile(fileList, encryptionKey, decrypted_filename)
assert read_binary_file(filename) == read_binary_file(decrypted_filename)
assert SHA256.new(read_binary_file(filename)).digest() == SHA256.new(read_binary_file(decrypted_filename)).digest()
address_gen = datamap.createDatamapGenerator(verifyingKey, None, 1)
for chunk in allChunksList[1:]: #first chunk is the treasure chunk and doesn't get signed when doing local simulations
data_chunk, signature = encryption.splitChunkAndSignature(chunk)
address = encryption.trytesToBytes(next(address_gen)[:-1])
encryption.verifyChunk(data_chunk + address, signature, verifyingKey.hex())
assert True
cleanup()
def test_verify_chunk_signatures(self):
_, verifyingKey = encryption.getKeypair(self.privateHandle)
address_gen = datamap.createDatamapGenerator(verifyingKey,
len(self.chunkList) + 1)
for chunk in self.chunkList:
datachunk, signature = encryption.splitChunkAndSignature(chunk)
address = encryption.trytesToBytes(next(address_gen)[:-1])
encryption.verifyChunk(datachunk + address, signature,
verifyingKey.hex())
assert True
def fileToChunks(filename, privateHandle, startingHash, password = None):
"""Takes a filename and returns the file converted to rev2 compliant chunks, already signed.
Arguments:
filename {str} -- Self-explanatory. Also needs to include the extension.
privateHandle {bytes} -- Bytestring to use as the private handle. Can and should be generated using encryption.getPrivateHandle().
startingHash {bytes} -- Hash on the main hashchain corresponding to the position of the first chunk of the file on the datamap.
Keyword Arguments:
password {str} -- Optional argument. Use it to password protect a particular file in a multi-file upload (default: {None})
Returns:
list -- Every element is a chunk, in the same order as the bytes are read from the file.
"""
signingKey, _ = encryption.getKeypair(privateHandle)
encryptionKey = encryption.getEncryptionKey(privateHandle)
f = open(filename, mode="rb")
filesize = os.path.getsize(filename)
chunksize = 1013
numberOfChunks = math.ceil(filesize/chunksize)
fileList = []
if password is not None:
encryptionKey = encryption.getEncryptionKey(encryptionKey + password.encode("utf-8"))
numberOfChunks = math.ceil((filesize - 997)/chunksize) + 1
chunksize = 997
address_gen = datamap.createDatamapGenerator(startingHash, numberOfChunks + 1)
for i in range(0, numberOfChunks):
chunk = f.read(chunksize)
encrypted_chunk, nonce, tag = encryption.encryptAES(chunk, encryptionKey)
address_trytes = next(address_gen)[:-1] #the real address is 81 chars, but the byte conversion only works with even numbers, so we use the first 80 chars of the address to sign and check
address_bytes = encryption.trytesToBytes(address_trytes)
if password is not None and i == 0:
unsigned_chunk = b"".join([encrypted_chunk, nonce, tag])
chunksize = 1013
else:
unsigned_chunk = b"".join([encrypted_chunk, nonce])
signature = encryption.signChunk(unsigned_chunk + address_bytes, signingKey)
completed_chunk = unsigned_chunk + signature
fileList.append(completed_chunk)
f.close()
return fileList