def processBuffer(self, buffer):
done = False
if (len(buffer) * 8 < self.numObservationBits):
print "ERROR: Received an incomplete buffer (%d), expexting (%d)" \
%( ( len( buffer ) * 8 ), self.numObservationBits )
done = True
else:
part = []
bufferedSamples = BitStream(buffer)
numObservationSamples = len(
self.spreadingCode) * Receiver.MULTIPLIER
for sampleIndex in range(numObservationSamples):
sampleValue = bufferedSamples.read(self.bitDepth)
for channelIndex in range(self.numberOfChannels - 1):
bufferedSamples.read(self.bitDepth)
sampleValue = struct.pack("!I", sampleValue)
sampleValue = struct.unpack("i", sampleValue)[0]
part.append(sampleValue * 1.0)
if (part != None and 0 < len(part)):
self.detectTrainingSequence(part)
self.numProcessedObservations += 1
done = (self.numProcessedObservations >=
self.maxNumberOfObservations)
return (done)
def extractSymbols(self, symbols, offset):
bitPacker = BitPacker()
bitStream = BitStream(False, bitPacker)
for i in range(offset, len(symbols)):
bitPacker.writeByte(symbols[i], 1)
data = bitStream.getRawBytes()
print "Data (%d):" % (len(data))
for i in range(len(data)):
if(i != 0 and i % 8 == 0):
print
print "0x%02x " % (ord(data[i])),
print
decodedData = self.decodeData(data)
print "Decoded data (%d):" % (len(decodedData))
for i in range(len(decodedData)):
if(i != 0 and i % 8 == 0):
print
print "0x%02x " % (ord(decodedData[i])),
print
print "Decoded string: '%s'" % (decodedData)
decodedSymbols = \
SymbolTracker.toList(self.bitsPerSymbol, decodedData)
return(decodedSymbols)
def encode(self, data):
if(self.checkParamterIsString(data)):
bitPacker = BitPacker()
bitStream = BitStream(False, bitPacker)
symbolTracker = SymbolTracker(
ManchesterEncoder.MESSAGE_LENGTH, data)
symbol = symbolTracker.getNextSymbol()
while(symbol is not None):
if(symbol == 1):
bitPacker.writeByte(
ManchesterEncoder.HI_SYMBOL,
ManchesterEncoder.BLOCK_LENGTH
)
elif(symbol == 0):
bitPacker.writeByte(
ManchesterEncoder.LO_SYMBOL,
ManchesterEncoder.BLOCK_LENGTH
)
else:
print "ERROR: Received unknown symbol (%d)." % (symbol)
symbol = symbolTracker.getNextSymbol()
return(bitStream.getRawBytes())
else:
return(None)
def decode(self, data, errorPositions=None):
if(self.codec and self.checkParamterIsString(data)):
bitPacker = BitPacker()
bitStream = BitStream(False, bitPacker)
symbolTracker = BitStream(False, data)
numberOfBlocks = \
int(
math.ceil(
float(symbolTracker.getSize()) /
float(self.blockLength)
)
)
for i in range(numberOfBlocks):
blockValues = [0 for j in range(self.numberOfBlockSymbols)]
buffer = symbolTracker.readBytes(self.blockLength)
for j in range(len(buffer)):
index = (i * self.numberOfBlockSymbols) + j
blockValues[j] = ord(buffer[j])
if (
errorPositions is not None and
index < len(errorPositions) and
errorPositions[index]
):
blockValues[j] = -1
message = \
self.codec.RSDecode(
blockValues,
(
self.numberOfBlockSymbols -
self.numberOfMessageSymbols
)
)
if(message is not None):
map(
lambda x:
bitPacker.writeByte(
x,
ReedSolomonEncoder.SYMBOL_SIZE_IN_BITS
),
message[0: self.numberOfMessageSymbols]
)
else:
for i in range(self.numberOfMessageSymbols):
bitPacker.writeByte(
0,
ReedSolomonEncoder.SYMBOL_SIZE_IN_BITS
)
return(bitStream.getRawBytes())
else:
print "ERROR: Codec was not initialized."
return(None)
def test_bit_extension(self):
"""
The real test function. I don't know how it works, but I think it will be cool
:return: dunno
"""
bit_stream = BitStream([])
test1 = bit_stream.extend_count(3)
test2 = bit_stream.extend_count(4)
self.assertEqual(len(test1), 8)
self.assertEqual(len(test2), 16)
def decode(self, fname):
self._qr.decode(fname)
bits = BitStream()
print(self._qr.data)
binData = base64.b64decode(self._qr.data)
for uint8 in binData:
byte = ord(uint8)
bits.write(8, byte)
print(bits)
self._processPolygons(bits)
def record(self, device):
if ( \
device.hasAppropriateStream ( \
CAHAL_DEVICE_INPUT_STREAM, \
self.numberOfChannels, \
self.bitDepth, \
self.sampleRate \
) \
):
flags = \
CAHAL_AUDIO_FORMAT_FLAGISSIGNEDINTEGER \
| CAHAL_AUDIO_FORMAT_FLAGISPACKED
BaseRecorder.bitPacker = BitPacker()
BaseRecorder.lock = _threading.Lock()
BaseRecorder.semaphore = _threading.Semaphore(0)
self.signal = BitStream(BaseRecorder.bitPacker)
if (
start_recording ( \
device.struct, \
CAHAL_AUDIO_FORMAT_LINEARPCM, \
self.numberOfChannels, \
self.sampleRate, \
self.bitDepth, \
bufferSamples, \
flags \
) \
):
print "Starting recording..."
self.processObservations()
print "Stopping recording..."
cahal_stop_recording()
print "Stopped recording."
else:
print "ERROR: Could not start recording."
else:
print "ERROR: Could not find an appropriate stream."
BaseRecorder.bitPacker = None
BaseRecorder.lock = None
BaseRecorder.semaphore = None
def encode(self, data):
if(self.codec and self.checkParamterIsString(data)):
bitPacker = BitPacker()
bitStream = BitStream(False, bitPacker)
symbolTracker = BitStream(False, data)
numberOfBlocks = \
int(
math.ceil(
float(symbolTracker.getSize()) /
float(self.messageLength)
)
)
for i in range(numberOfBlocks):
blockValues = [chr(0)
for i in range(self.numberOfMessageSymbols)]
buffer = symbolTracker.readBytes(self.messageLength)
for i in range(len(buffer)):
blockValues[i] = buffer[i]
codeword = \
self.codec.RSEncode(
blockValues,
(
self.numberOfBlockSymbols -
self.numberOfMessageSymbols
)
)
map(
lambda x:
bitPacker.writeByte(
x,
ReedSolomonEncoder.SYMBOL_SIZE_IN_BITS
),
codeword
)
return(bitStream.getRawBytes())
else:
print "ERROR: Codec was not initialized."
return(None)
def encrypt_text(self, text, pad_to=None, task_monitor=None):
"""
Encrypts the given string into a ciphertext object.
Arguments:
text::string -- A string to encrypt.
pad_to::int -- Minimum size (in bytes) of the resulting
ciphertext. Data will be padded before
encryption to match this size.
task_monitor::TaskMonitor -- A task monitor for this task.
Returns:
ciphertext:Ciphertext -- A ciphertext object encapsulating the
encrypted data.
"""
bitstream = BitStream()
bitstream.put_string(text)
return self.encrypt_bitstream(bitstream, pad_to, task_monitor)
def encrypt_text(self, text, pad_to=None, task_monitor=None):
"""
Encrypts the given string into a ciphertext object.
Arguments:
text::string -- A string to encrypt.
pad_to::int -- Minimum size (in bytes) of the resulting
ciphertext. Data will be padded before
encryption to match this size.
task_monitor::TaskMonitor -- A task monitor for this task.
Returns:
ciphertext:Ciphertext -- A ciphertext object encapsulating the
encrypted data.
"""
bitstream = BitStream()
bitstream.put_string(text)
return self.encrypt_bitstream(bitstream, pad_to, task_monitor)
def transmit( self, device, message ):
if ( \
device.hasAppropriateStream ( \
CAHAL_DEVICE_OUTPUT_STREAM, \
self.numberOfChannels, \
self.bitDepth, \
self.sampleRate \
) \
):
print "Preparing signal for message: %s." %( message )
symbolTracker = BitStream( message )
bitPacker = BitPacker()
numSymbols = symbolTracker.getSize() / self.bitsPerSymbol
numSamples = numSymbols * self.samplesPerSymbol
duration = math.ceil( numSamples / self.sampleRate )
print "Buffering up to 5 seconds of audio."
numSymbolsToRead = \
math.ceil( self.sampleRate / self.samplesPerSymbol * 5 )
print "Symbols to read per iteration is 0x%x." %( numSymbolsToRead )
hasRemaining = \
self.bufferSymbols (
symbolTracker,
bitPacker,
numSymbolsToRead
)
self.sendSignal (
device,
symbolTracker,
bitPacker,
duration,
hasRemaining,
numSymbolsToRead
)
else:
print "ERROR: Could not find an appropriate stream."
def _encrypted_data_as_bitstream(self):
"""
Returns the contents of this ciphertext as a BitStream object.
This includes only the encrypted data (gamma and delta components), not
the nbits and public key fingerprint metadata.
The components are encoded alternating as follows:
[gamma[0], delta[0], gamma[1], delta[1], ...]
with each component represented as a nbits long number.
Returns:
bitstream::BitStream -- The gamma and delta components of this
ciphertext as a bitstream.
"""
bitstream = BitStream()
for i in range(0, self.get_length()):
bitstream.put_num(self.gamma[i], self.nbits)
bitstream.put_num(self.delta[i], self.nbits)
return bitstream
def _encrypted_data_as_bitstream(self):
"""
Returns the contents of this ciphertext as a BitStream object.
This includes only the encrypted data (gamma and delta components), not
the nbits and public key fingerprint metadata.
The components are encoded alternating as follows:
[gamma[0], delta[0], gamma[1], delta[1], ...]
with each component represented as a nbits long number.
Returns:
bitstream::BitStream -- The gamma and delta components of this
ciphertext as a bitstream.
"""
bitstream = BitStream()
for i in range(0, self.get_length()):
bitstream.put_num(self.gamma[i], self.nbits)
bitstream.put_num(self.delta[i], self.nbits)
return bitstream
def processBuffer(self, buffer):
done = False
if len(buffer) * 8 < self.numObservationBits:
print "ERROR: Received an incomplete buffer (%d), expexting (%d)" % (
(len(buffer) * 8),
self.numObservationBits,
)
done = True
else:
part = []
bufferedSamples = BitStream(buffer)
for sampleIndex in range(self.numObservationSamples):
sampleValue = bufferedSamples.read(self.bitDepth)
for channelIndex in range(self.numberOfChannels - 1):
bufferedSamples.read(self.bitDepth)
sampleValue = struct.pack("!I", sampleValue)
sampleValue = struct.unpack("i", sampleValue)[0]
part.append(sampleValue * 1.0)
if 0 < len(part):
if self.applyFilter:
part = python_filter_signal(self.widebandFilter, part)
if 0 == (self.numProcessedObservations % int(self.graphPeriod)):
self.graphFFT(part)
self.calculateEnergy(part)
self.numProcessedObservations += 1
done = self.numProcessedObservations >= self.numObservations
return done
def decode(self, data, errorPositions=None):
if(self.checkParamterIsString(data)):
bitPacker = BitPacker()
bitStream = BitStream(False, bitPacker)
symbolTracker = SymbolTracker(ManchesterEncoder.BLOCK_LENGTH, data)
symbol = symbolTracker.getNextSymbol()
errorBitPositions = []
while(symbol is not None):
if(symbol == ManchesterEncoder.HI_SYMBOL):
bitPacker.writeByte(1, 1)
elif(symbol == ManchesterEncoder.LO_SYMBOL):
bitPacker.writeByte(0, 1)
else:
print \
"WARN: Received unknown symbol (0x%x) at position %d."\
% (symbol, bitStream.getSize())
errorBitPositions.append(bitStream.getSize())
bitPacker.writeByte(1, 1)
symbol = symbolTracker.getNextSymbol()
buffer = bitStream.getRawBytes()
if(errorPositions is not None):
for i in range(len(buffer)):
errorPositions.append(False)
for bitPosition in errorBitPositions:
bytePosition = int(math.floor(bitPosition / 8))
errorPositions[bytePosition] = True
return(buffer)
else:
return(None)
def processBuffer( self, buffer ):
done = False
if( len( buffer ) * 8 < self.numObservationBits ):
print "ERROR: Received an incomplete buffer (%d), expexting (%d)" \
%( ( len( buffer ) * 8 ), self.numObservationBits )
done = True
else:
part = []
bufferedSamples = BitStream( buffer )
for sampleIndex in range( self.numObservationSamples ):
sampleValue = bufferedSamples.read( self.bitDepth )
for channelIndex in range( self.numberOfChannels - 1 ):
bufferedSamples.read( self.bitDepth )
sampleValue = struct.pack( "!I", sampleValue )
sampleValue = struct.unpack( "i", sampleValue )[ 0 ]
part.append( sampleValue * 1.0 )
if( 0 < len( part ) ):
if( self.applyFilter ):
part = python_filter_signal( self.widebandFilter, part )
if( 0 == ( self.numProcessedObservations % int( self.graphPeriod ) ) ):
self.graphFFT( part )
self.calculateEnergy( part )
self.numProcessedObservations += 1
done = ( self.numProcessedObservations >= self.numObservations )
return( done )
def transmit(self, device, message):
if ( \
device.hasAppropriateStream ( \
CAHAL_DEVICE_OUTPUT_STREAM, \
self.numberOfChannels, \
self.bitDepth, \
self.sampleRate \
) \
):
print "Preparing signal for message: %s." % (message)
symbolTracker = BitStream(message)
bitPacker = BitPacker()
numSymbols = symbolTracker.getSize() / self.bitsPerSymbol
numSamples = numSymbols * self.samplesPerSymbol
duration = math.ceil(numSamples / self.sampleRate)
print "Buffering up to 5 seconds of audio."
numSymbolsToRead = \
math.ceil( self.sampleRate / self.samplesPerSymbol * 5 )
print "Symbols to read per iteration is 0x%x." % (numSymbolsToRead)
hasRemaining = \
self.bufferSymbols (
symbolTracker,
bitPacker,
numSymbolsToRead
)
self.sendSignal(device, symbolTracker, bitPacker, duration,
hasRemaining, numSymbolsToRead)
else:
print "ERROR: Could not find an appropriate stream."
def decode(self, data, errorPositions=None):
if (self.codec and self.checkParamterIsString(data)):
bitPacker = BitPacker()
bitStream = BitStream(False, bitPacker)
symbolTracker = BitStream(False, data)
numberOfBlocks = \
int(
math.ceil(
float(symbolTracker.getSize()) /
float(self.blockLength)
)
)
for i in range(numberOfBlocks):
blockValues = [0 for j in range(self.numberOfBlockSymbols)]
buffer = symbolTracker.readBytes(self.blockLength)
for j in range(len(buffer)):
index = (i * self.numberOfBlockSymbols) + j
blockValues[j] = ord(buffer[j])
if (errorPositions is not None
and index < len(errorPositions)
and errorPositions[index]):
blockValues[j] = -1
message = \
self.codec.RSDecode(
blockValues,
(
self.numberOfBlockSymbols -
self.numberOfMessageSymbols
)
)
if (message is not None):
map(
lambda x: bitPacker.writeByte(
x, ReedSolomonEncoder.SYMBOL_SIZE_IN_BITS),
message[0:self.numberOfMessageSymbols])
else:
for i in range(self.numberOfMessageSymbols):
bitPacker.writeByte(
0, ReedSolomonEncoder.SYMBOL_SIZE_IN_BITS)
return (bitStream.getRawBytes())
else:
print "ERROR: Codec was not initialized."
return (None)
def sendSignal(self, device, symbolTracker, bitPacker, duration,
hasRemaining, numSymbolsToRead):
flags = \
CAHAL_AUDIO_FORMAT_FLAGISSIGNEDINTEGER \
| CAHAL_AUDIO_FORMAT_FLAGISPACKED
Transmitter.signal = BitStream(bitPacker)
Transmitter.lock = _threading.Lock()
print "Duration is %d seconds." % (duration)
if (
start_playback ( \
device.struct, \
CAHAL_AUDIO_FORMAT_LINEARPCM, \
self.numberOfChannels, \
self.sampleRate, \
self.bitDepth, \
playback, \
flags \
) \
):
startTime = calendar.timegm(time.gmtime())
while (hasRemaining):
hasRemaining = \
self.bufferSymbols( symbolTracker, bitPacker, numSymbolsToRead )
endTime = calendar.timegm(time.gmtime())
duration -= int(endTime - startTime)
if (0 > duration):
duation = 0
duration = struct.unpack("I", struct.pack("i", duration))[0]
cahal_sleep(duration * 1000)
if (cahal_stop_playback()):
print "Transmit stopped."
else:
print "ERROR: Could not stop playback."
else:
print "ERROR: Could not start playing."
Transmitter.lock = None
def record( self, device ):
if ( \
device.hasAppropriateStream ( \
CAHAL_DEVICE_INPUT_STREAM, \
self.numberOfChannels, \
self.bitDepth, \
self.sampleRate \
) \
):
flags = \
CAHAL_AUDIO_FORMAT_FLAGISSIGNEDINTEGER \
| CAHAL_AUDIO_FORMAT_FLAGISPACKED
BaseRecorder.bitPacker = BitPacker()
BaseRecorder.lock = _threading.Lock()
BaseRecorder.semaphore = _threading.Semaphore( 0 )
self.signal = BitStream( BaseRecorder.bitPacker )
if (
start_recording ( \
device.struct, \
CAHAL_AUDIO_FORMAT_LINEARPCM, \
self.numberOfChannels, \
self.sampleRate, \
self.bitDepth, \
bufferSamples, \
flags \
) \
):
print "Starting recording..."
self.processObservations()
print "Stopping recording..."
cahal_stop_recording()
print "Stopped recording."
else:
print "ERROR: Could not start recording."
else:
print "ERROR: Could not find an appropriate stream."
BaseRecorder.bitPacker = None
BaseRecorder.lock = None
BaseRecorder.semaphore = None
def encode(self, data):
if (self.codec and self.checkParamterIsString(data)):
bitPacker = BitPacker()
bitStream = BitStream(False, bitPacker)
symbolTracker = BitStream(False, data)
numberOfBlocks = \
int(
math.ceil(
float(symbolTracker.getSize()) /
float(self.messageLength)
)
)
for i in range(numberOfBlocks):
blockValues = [
chr(0) for i in range(self.numberOfMessageSymbols)
]
buffer = symbolTracker.readBytes(self.messageLength)
for i in range(len(buffer)):
blockValues[i] = buffer[i]
codeword = \
self.codec.RSEncode(
blockValues,
(
self.numberOfBlockSymbols -
self.numberOfMessageSymbols
)
)
map(
lambda x: bitPacker.writeByte(
x, ReedSolomonEncoder.SYMBOL_SIZE_IN_BITS), codeword)
return (bitStream.getRawBytes())
else:
print "ERROR: Codec was not initialized."
return (None)
def verify(self, original_collection, shuffled_collection):
"""
Verifies that original_collection and shuffled_collection are
equivalent as proven by this ShufflingProof object.
If this method returns true, then we have proof that both collections
contain encryptions of the same collection of plaintexts, save for the
negligible probability (for a correct security parameter configured in
params.py) that the zero-knowledge proof has been faked. Otherwise we
gain no information about the two collections, other than they are not
shown to be equivalent by this particular proof.
ShufflingProof is a zero-knowledge proof: the result of this
verification or the information within the ShufflingProof object for
which two collections pass this verification, provide no information as
to the association of particular ciphertexts in original_collection
with particular ciphertexts of shuffled_collection.
Arguments:
original_collection::CiphertextCollection --
The original collection of ciphertexts.
shuffled_collection::CiphertextCollection --
Another collection for which we wish to know if the current
ShufflingProof object demonstrates equivalence with
original_collection.
Returns:
result::bool -- True if this proof shows both collections to be
equivalent.
False otherwise.
"""
# Get the security parameter P with which the proof was originally
# created. This is reflect in the length of self._collections and
# self._mappings.
assert len(self._collections) == len(self._mappings), \
"The length of the private properties self._collections and " \
"self._mappings of ShufflingProof must always be the same."
security_parameter = len(self._collections)
# Get the security parameter specified in params
minimum_allowed_security_parameter = params.SHUFFLING_PROOF_SECURITY_PARAMETER
# Check that the security parameter is <= 256, since that is the most
# bits of challenge we can currently have. Also check that P is at least 1
if(minimum_allowed_security_parameter < 1 or
minimum_allowed_security_parameter > 256):
raise ValueError("Security parameter for shuffling proof " \
"(params.SHUFFLING_PROOF_SECURITY_PARAMETER) is out of " \
"range. The security parameter must be between 1 and 256, "\
"its current value is %d. If you have set " \
"CUSTOM_SHUFFLING_PROOF_SECURITY_PARAMETER in the file " \
"params.py, please correct this value or set it to None, " \
"in order for the security parameter to be decided based " \
"on the global SECURITY_LEVEL of plonevotecryptolib. It " \
"is recommended that " \
"CUSTOM_SHUFFLING_PROOF_SECURITY_PARAMETER be always set " \
"to None for deployment operation of plonevotecryptolib." \
% security_parameter)
# Check that the security parameter for which the proof was generated
# is correct and meets the security standards declared in params.py
if(security_parameter < minimum_allowed_security_parameter or
security_parameter < 1 or
security_parameter > 256):
raise InvalidShuffilingProofError("The security parameter for " \
"(which the current proof was created is %d. This is " \
"(either an incorrect value (outside of the [1,256] " \
"(range) or not secure enough to meet the standards set " \
"(in the configuration of params.py (< %d). The proof " \
"(is thus invalid." \
% (security_parameter,
minimum_allowed_security_parameter))
# Generate the challenge
challenge = \
self._generate_challenge(original_collection, shuffled_collection)
# Verify that the challenge corresponds to the stored one
if(challenge != self._challenge):
return False
# Get the challenge as a BitStream for easier manipulation
challenge_bits = BitStream()
challenge_bits.put_hex(challenge)
challenge_bits.seek(0) # back to the beginning of the stream
# For each of the first P bits in the stream
for i in range(0, security_parameter):
bit = challenge_bits.get_num(1)
if(bit == 0):
# verify that self._mapping[i] maps original_collection into
# self._collections[i]
if(not self._mappings[i].verify(original_collection,
self._collections[i])):
return False
elif(bit == 1):
# verify that self._mapping[i] self._collections[i] into
# self._collections[i]
if(not self._mappings[i].verify(self._collections[i],
shuffled_collection)):
return False
else:
assert False, "We took a single bit, its value must be either "\
"0 or 1."
# If we made it so far, the proof is correct
# (each mapping is in accordance to the challenge and valid)
return True
def new(cls, original_collection, shuffled_collection, mapping):
"""
Constructs a new proof of equivalence between original_collection and
shuffled_collection.
This method should not be used outside of plonevotecryptolib.Mixnet.
Consider using CiphertextCollection.shuffle_with_proof() instead.
The given CiphertextCollectionMapping must be a valid mapping between
original_collection and shuffled_collection.
Arguments:
original_collection::CiphertextCollection --
The original collection to be shuffled.
shuffled_collection::CiphertextCollection --
The shuffled collection resulting from applying mapping to
original_collection.
mapping::CiphertextCollectionMapping --
The mapping between original_collection and shuffled_collection.
Returns:
proof::ShufflingProof --
The zero-knowledge proof of equivalence between
original_collection and shuffled_collection.
Throws:
InvalidCiphertextCollectionMappingError --
If mapping is not a valid mapping between original_collection
and shuffled_collection.
ValueError --
If params.SHUFFLING_PROOF_SECURITY_PARAMETER is within an
invalid range.
"""
# Check that we have a valid mapping between the two collections:
if(not mapping.verify(original_collection, shuffled_collection)):
raise InvalidCiphertextCollectionMappingError( \
"mapping was expected to be a CiphertextCollectionMapping "\
"object representing a valid mapping between "\
"original_collection and shuffled_collection. However, "\
"mapping.verify(original_collection, shuffled_collection) "\
"returns False. A zero-knowledge proof of equivalence "\
"between two shuffled collections cannot be constructed "\
"without first having a valid mapping between them.")
# Get the security parameter P
security_parameter = params.SHUFFLING_PROOF_SECURITY_PARAMETER
# Check that the security parameter is <= 256, since that is the most
# bits of challenge we can currently have. Also check that P is at least 1
if(security_parameter < 1 or security_parameter > 256):
raise ValueError("Security parameter for shuffling proof " \
"(params.SHUFFLING_PROOF_SECURITY_PARAMETER) is out of " \
"range. The security parameter must be between 1 and 256, "\
"its current value is %d. If you have set " \
"CUSTOM_SHUFFLING_PROOF_SECURITY_PARAMETER in the file " \
"params.py, please correct this value or set it to None, " \
"in order for the security parameter to be decided based " \
"on the global SECURITY_LEVEL of plonevotecryptolib. It " \
"is recommended that " \
"CUSTOM_SHUFFLING_PROOF_SECURITY_PARAMETER be always set " \
"to None for deployment operation of plonevotecryptolib." \
% security_parameter)
# Construct a new empty proof
proof = ShufflingProof()
# Populate proof._collections with P random shuffles of
# original_collection. We save each mapping for now in proof._mappings.
# (ie. every mapping in proof._mappings[i] will initially be from the
# original collection into proof._collections[i])
# generate new mappings in parallel
pool = multiprocessing.Pool()
async_params = [original_collection] * security_parameter
generate_mappings_pool = pool.map_async(new_collection_mapping, async_params)
for new_mapping in generate_mappings_pool.get(99999999):
proof._mappings.append(new_mapping)
proof._collections.append(new_mapping.apply(original_collection))
pool.close()
pool.join()
# Generate the challenge
proof._challenge = \
proof._generate_challenge(original_collection, shuffled_collection)
# Get the challenge as a BitStream for easier manipulation
challenge_bits = BitStream()
challenge_bits.put_hex(proof._challenge)
challenge_bits.seek(0) # back to the beginning of the stream
# For each of the first P bits in the stream
for i in range(0, security_parameter):
## print "Processing challenge bit %d" % i # replace with TaskMonitor API calls
bit = challenge_bits.get_num(1)
if(bit == 0):
# Do nothing.
# proof._mappings[i] is already a mapping from
# original_collection unto proof._collections[i]
pass
elif(bit == 1):
# Change proof._mappings[i] to be a mapping from
# proof._collections[i] unto shuffled_collection, using
# CiphertextCollectionMapping.rebase(...)
# rebase(O->D, O->C_{i}) => C_{i}->D
rebased_mapping = mapping.rebase(proof._mappings[i])
# Replace O->C_{i} with C_{i}->D
proof._mappings[i] = rebased_mapping
else:
assert False, "We took a single bit, its value must be either "\
"0 or 1."
# return the proof object
return proof
class BaseRecorder:
bitPacker = None
lock = None
semaphore = None
numObservationBits = None
def __init__ (
self, bitDepth, numberOfChannels, sampleRate, widebandFirstStopband,
widebandFirstPassband, widebandSecondPassband, widebandSecondStopband,
passbandAttenuation, stopbandAttenuation, outputFileName, filter,
writeOutput
):
self.signal = None
self.bitDepth = bitDepth
self.numberOfChannels = numberOfChannels
self.sampleRate = int( sampleRate )
self.widebandFirstStopband = widebandFirstStopband
self.widebandFirstPassband = widebandFirstPassband
self.widebandSecondPassband = widebandSecondPassband
self.widebandSecondStopband = widebandSecondStopband
self.passbandAttenuation = passbandAttenuation
self.stopbandAttenuation = stopbandAttenuation
self.writeOutput = writeOutput
self.applyFilter = filter
if( self.writeOutput ):
self.outputFileName = outputFileName
else:
self.outputFileName = None
if( self.applyFilter ):
self.widebandFilter = \
python_initialize_kaiser_filter (
self.widebandFirstStopband,
self.widebandFirstPassband,
self.widebandSecondPassband,
self.widebandSecondStopband,
self.passbandAttenuation,
self.stopbandAttenuation,
int( self.sampleRate )
)
else:
self.widebandFilter = None
def record( self, device ):
if ( \
device.hasAppropriateStream ( \
CAHAL_DEVICE_INPUT_STREAM, \
self.numberOfChannels, \
self.bitDepth, \
self.sampleRate \
) \
):
flags = \
CAHAL_AUDIO_FORMAT_FLAGISSIGNEDINTEGER \
| CAHAL_AUDIO_FORMAT_FLAGISPACKED
BaseRecorder.bitPacker = BitPacker()
BaseRecorder.lock = _threading.Lock()
BaseRecorder.semaphore = _threading.Semaphore( 0 )
self.signal = BitStream( BaseRecorder.bitPacker )
if (
start_recording ( \
device.struct, \
CAHAL_AUDIO_FORMAT_LINEARPCM, \
self.numberOfChannels, \
self.sampleRate, \
self.bitDepth, \
bufferSamples, \
flags \
) \
):
print "Starting recording..."
self.processObservations()
print "Stopping recording..."
cahal_stop_recording()
print "Stopped recording."
else:
print "ERROR: Could not start recording."
else:
print "ERROR: Could not find an appropriate stream."
BaseRecorder.bitPacker = None
BaseRecorder.lock = None
BaseRecorder.semaphore = None
def processObservations( self ):
done = False
while( not done ):
buffer = None
nBitsToRead = self.getNumberOfBitsToRead()
BaseRecorder.semaphore.acquire( True )
BaseRecorder.lock.acquire( True )
availableData = self.signal.getSize()
BaseRecorder.lock.release()
#print "Available %d, waiting for %d." %( availableData, nBitsToRead )
while( availableData >= nBitsToRead and not done ):
BaseRecorder.lock.acquire( True )
buffer = self.signal.read( nBitsToRead )
BaseRecorder.lock.release()
if( None != buffer ):
done = self.processBuffer( buffer )
nBitsToRead = self.getNumberOfBitsToRead()
BaseRecorder.lock.acquire( True )
availableData = self.signal.getSize()
BaseRecorder.lock.release()
#print "Available %d, waiting for %d." %( availableData, nBitsToRead )
def getNumberOfBitsToRead( self ):
return( 0 )
def processbuffer( self, buffer ):
return( True )
def __del__( self ):
if( self.writeOutput ):
WAVRecorder.saveSignalToWAV (
self.signal, self.outputFileName, self.numberOfChannels,
self.bitDepth, self.sampleRate
)
if( self.signal ):
self.signal = None
if( self.widebandFilter ):
csignal_destroy_passband_filter( self.widebandFilter )
BaseRecorder.bitPacker = None
BaseRecorder.lock = None
BaseRecorder.semaphore = None
BaseRecorder.numObservationBits = None
def decompress_video(self, decompress_path):
with open(decompress_path, "wb") as write_stream:
#Get the bitstream to read the compression
read_stream = BitStream(self.file_path)
read_stream.set_offset(len(self.header) * 8)
#Write the header for the video
write_stream.write(self.header.encode())
write_stream.write("FRAME\n".encode())
#This marks the start of decompression
number_of_numbers = 0
array_of_nums = []
counter = 0
counter_bits = 0
while read_stream.read_bits(5000):
got_number = self.gomby.add_bits(read_stream.get_bit_array())
read_stream.delete_bits(5000)
counter_bits += 1
if got_number:
nums = self.gomby.decode_nums()
number_of_numbers += len(nums)
array_of_nums += nums
print("Decompressed", number_of_numbers)
print("Need to get", self.frame.limit_to_convert)
if number_of_numbers >= self.frame.limit_to_convert:
counter += 1
print("Decompressing frame: ", counter)
array_of_nums = self.frame.set_frame_by_array(
array_of_nums)
y, u, v = self.frame.decompress_frame(self.decompress_mode)
write_stream.write(y.astype(np.uint8))
write_stream.write(u.astype(np.uint8))
write_stream.write(v.astype(np.uint8))
write_stream.write("FRAME\n".encode())
number_of_numbers -= self.frame.limit_to_convert
print("Finished writing decompressed frame, now only have",
number_of_numbers)
num_bits = read_stream.read_allbits()
got_number = self.gomby.add_bits(read_stream.get_bit_array())
if got_number:
nums = self.gomby.decode_nums()
array_of_nums += nums
## At this point we have all of the frame saved in memory, we will now start to divide it in frames to proceed to decompressing
array_of_nums = self.frame.set_frame_by_array(array_of_nums)
y, u, v = self.frame.decompress_frame(self.decompress_mode)
write_stream.write(y.astype(np.uint8))
write_stream.write(u.astype(np.uint8))
write_stream.write(v.astype(np.uint8))
print("Finished writing decompressed frame")
#girar
print("Finished writing decompressed frame")
def decrypt_to_bitstream(self, ciphertext, task_monitor=None, force=False):
"""
Decrypts the given ciphertext into a bitstream.
If the bitstream was originally encrypted with PublicKey.encrypt_X(),
then this method returns a bitstream following the format described
in Note 001 of the Ciphertext.py file:
[size (64 bits) | message (size bits) | padding (X bits) ]
Arguments:
ciphertext::Ciphertext -- An encrypted Ciphertext object.
task_monitor::TaskMonitor -- A task monitor for this task.
force:bool -- Set this to true if you wish to force a decryption
attempt, even when the ciphertext's stored public key
fingerprint does not match that of the public key
associated with this private key.
Returns:
bitstream::Bitstream -- A bitstream containing the unencrypted
data.
Throws:
IncompatibleCiphertextError -- The given ciphertext does not appear
to be decryptable with the selected
private key.
"""
# Check that the public key fingerprint stored in the ciphertext
# matches the public key associated with this private key.
if(not force):
if(ciphertext.nbits != self.cryptosystem.get_nbits()):
raise IncompatibleCiphertextError("The given ciphertext is " \
"not decryptable with the selected private key: " \
"incompatible cryptosystem/key sizes.")
if(ciphertext.pk_fingerprint != self.public_key.get_fingerprint()):
raise IncompatibleCiphertextError("The given ciphertext is " \
"not decryptable with the selected private key: " \
"public key fingerprint mismatch.")
# We read and decrypt the ciphertext block by block
# See "Handbook of Applied Cryptography" Algorithm 8.18
bitstream = BitStream()
block_size = self.cryptosystem.get_nbits() - 1
prime = self.cryptosystem.get_prime()
key = self._key
# Check if we have a task monitor and register with it
if(task_monitor != None):
# One tick per block
ticks = ciphertext.get_length()
decrypt_task_mon = \
task_monitor.new_subtask("Decrypt data", expected_ticks = ticks)
for gamma, delta in ciphertext:
assert max(gamma, delta) < 2**(block_size + 1), \
"The ciphertext object includes blocks larger than the " \
"expected block size."
m = (pow(gamma, prime - 1 - key, prime) * delta) % prime
bitstream.put_num(m, block_size)
if(task_monitor != None): decrypt_task_mon.tick()
return bitstream
def encrypt_bitstream(self, bitstream, pad_to=None, task_monitor=None):
"""
Encrypts the given bitstream into a ciphertext object.
Arguments:
bitstream::BitStream-- A stream of bits to encrypt
(see BitStream utility class).
pad_to::int -- Minimum size (in bytes) of the resulting
ciphertext. Data will be padded before
encryption to match this size.
task_monitor::TaskMonitor -- A task monitor for this task.
Returns:
ciphertext:Ciphertext -- A ciphertext object encapsulating the
encrypted data.
"""
random = StrongRandom()
## PART 1
# First, format the bitstream as per Ciphertext.py Note 001,
# previous to encryption.
# [size (64 bits) | message (size bits) | padding (X bits) ]
##
formated_bitstream = BitStream()
# The first 64 encode the size of the actual data in bits
SIZE_BLOCK_LENGTH = 64
size_in_bits = bitstream.get_length()
if(size_in_bits >= 2**SIZE_BLOCK_LENGTH):
raise ValueError("The size of the bitstream to encrypt is larger " \
"than 16 Exabits. The current format for " \
"PloneVote ciphertext only allows encrypting a " \
"maximum of 16 Exabits of information.")
formated_bitstream.put_num(size_in_bits, SIZE_BLOCK_LENGTH)
# We then copy the contents of the original bitstream
bitstream.seek(0)
formated_bitstream.put_bitstream_copy(bitstream)
# Finally, we append random data until we reach the desired pad_to
# length
unpadded_length = formated_bitstream.get_length()
if(pad_to != None and (pad_to * 8) > unpadded_length):
full_length = pad_to * 8
else:
full_length = unpadded_length
padding_left = full_length - unpadded_length
while(padding_left > 1024):
padding_bits = random.randint(1, 2**1024)
formated_bitstream.put_num(padding_bits,1024)
padding_left -= 1024
if(padding_left > 0):
padding_bits = random.randint(1, 2**padding_left)
formated_bitstream.put_num(padding_bits, padding_left)
padding_left = 0
## PART 2
# We encrypt the formated bitsteam using ElGamal into a Ciphertext
# object.
# See "Handbook of Applied Cryptography" Algorithm 8.18
##
# block_size is the size of each block of bits to encrypt
# since we can only encrypt messages in [0, p - 1]
# we should use (nbits - 1) as the block size, where
# 2**(nbits - 1) < p < 2**nbits
block_size = self.cryptosystem.get_nbits() - 1
prime = self.cryptosystem.get_prime()
generator = self.cryptosystem.get_generator()
# We pull data from the bitstream one block at a time and encrypt it
formated_bitstream.seek(0)
ciphertext = \
Ciphertext(self.cryptosystem.get_nbits(), self.get_fingerprint())
plaintext_bits_left = formated_bitstream.get_length()
# Check if we have a task monitor and register with it
if(task_monitor != None):
# We will do two tick()s per block to encrypt: one for generating
# the gamma component of the ciphertext block and another for the
# delta component (those are the two time intensive steps,
# because of exponentiation).
ticks = math.ceil((1.0 * plaintext_bits_left) / block_size) * 2
encrypt_task_mon = \
task_monitor.new_subtask("Encrypt data", expected_ticks = ticks)
while(plaintext_bits_left > 0):
# get next block (message, m, etc) to encrypt
if(plaintext_bits_left >= block_size):
block = formated_bitstream.get_num(block_size)
plaintext_bits_left -= block_size
else:
block = formated_bitstream.get_num(plaintext_bits_left)
# Encrypt as if the stream was filled with random data past its
# end, this avoids introducing a 0's gap during decryption to
# bitstream
displacement = block_size - plaintext_bits_left
block = block << displacement
padding = random.randint(0, 2**displacement - 1)
assert (padding / 2**displacement == 0), \
"padding should be at most displacement bits long"
block = block | padding
plaintext_bits_left = 0
# Select a random integer k, 1 <= k <= p − 2
k = random.randint(1, prime - 2)
# Compute gamma and delta
gamma = pow(generator, k, prime)
if(task_monitor != None): encrypt_task_mon.tick()
delta = (block * pow(self._key, k, prime)) % prime
if(task_monitor != None): encrypt_task_mon.tick()
# Add this encrypted data portion to the ciphertext object
ciphertext.append(gamma, delta)
# return the ciphertext object
return ciphertext
class Ciphertext:
"""
An object representing encrypted PloneVote data.
Ciphertext objects are created by PublicKey encrypt operations and
decrypted through PrivateKey decrypt methods (or through
ThresholdDecryptionCombinator if the data was encrypted with a threshold
public key and all partial decryptions are available).
This class can also be store to and loaded from file using the PloneVote
armored ciphertext XML format.
Attributes:
nbits::int -- Size in bits of the cryptosystem/public key used to
encrypt this ciphertext.
pk_fingerprint::string -- A fingerprint of the public key used to
encrypt this ciphertext. This fingerprint can
then be compared with the result from
PublicKey.get_fingerprint() to check for
compatibility with a given key pair or
threshold public key.
gamma::long[]
delta::long[] -- :
This two attributes should only be accessed by key classes within
PloneVoteCryptoLib.
See "Handbook of Applied Cryptography" Algorithm 8.18 for the
meaning of the variables. An array is used because the encrypted
data might be longer than the cryptosystem's bit size.
"""
def to_dict(self):
return {'a': self.gamma, 'b': self.delta}
def get_length(self):
"""
Returns the length, in blocks, of the ciphertext.
"""
assert len(self.gamma) == len(self.delta), "Each gamma component of " \
"the ciphertext must correspond " \
" to one delta component."
return len(self.gamma)
def __getitem__(self, i):
"""
Makes this object indexable.
Returns:
(gamma, delta)::(long, long) -- Returns the gamma, delta pair
representing a particular block
of the encrypted data.
Use ciphertext[i] for block i.
"""
return (self.gamma[i], self.delta[i])
def __iter__(self):
"""
Return an iterator (CiphertextIterator) for the current ciphertext.
"""
return CiphertextIterator(self)
def __eq__(self, other):
"""
Implements Ciphertext equality.
Two ciphertexts are equal if they have the same bit size, public key
fingerprint and list of gamma and delta components. A ciphertext is not
equal to any object of a different type.
"""
if (isinstance(other, Ciphertext) and (other.nbits == self.nbits)
and (other.pk_fingerprint == self.pk_fingerprint)
and (other.gamma == self.gamma)
and (other.delta == self.delta)):
return True
else:
return False
def __ne__(self, other):
"""
Implements Ciphertext inequality.
See __eq__(...) for the definition of Ciphertext equality,
inequality its is negation.
"""
return not self.__eq__(other)
def get_fingerprint(self):
"""
Gets a fingerprint of the current ciphertext.
A ciphertext fingerprint is generated as a SHA-256 hash of the
ciphertext, block by block.
Returns:
fingerprint::string -- A SHA-256 hexdigest providing a fingerprint
of the current ciphertext.
"""
fingerprint = sha256()
for (gamma, delta) in self:
fingerprint.update(hex(gamma))
fingerprint.update(hex(delta))
return fingerprint.hexdigest()
def __init__(self, nbits, public_key_fingerprint):
"""
Create an empty ciphertext object.
Arguments:
nbits::int -- Size in bits of the cryptosystem/public key used
to encrypt this ciphertext.
public_key_fingerprint::string -- The fingerprint of the public
key used to encrypt this data.
"""
self.gamma = []
self.delta = []
self.nbits = nbits
self.pk_fingerprint = public_key_fingerprint
def append(self, gamma, delta):
"""
Used internally by PublicKey.
This method adds an encrypted block of data with its gamma and delta
components from ElGamal (see HoAC Alg. 8.18).
"""
self.gamma.append(gamma)
self.delta.append(delta)
def _encrypted_data_as_bitstream(self):
"""
Returns the contents of this ciphertext as a BitStream object.
This includes only the encrypted data (gamma and delta components), not
the nbits and public key fingerprint metadata.
The components are encoded alternating as follows:
[gamma[0], delta[0], gamma[1], delta[1], ...]
with each component represented as a nbits long number.
Returns:
bitstream::BitStream -- The gamma and delta components of this
ciphertext as a bitstream.
"""
bitstream = BitStream()
for i in range(0, self.get_length()):
bitstream.put_num(self.gamma[i], self.nbits)
bitstream.put_num(self.delta[i], self.nbits)
return bitstream
def _encrypted_data_as_base64(self):
"""
Returns the contents of this ciphertext as a base64 string.
This includes only the encrypted data (gamma and delta components), not
the nbits and public key fingerprint metadata.
"""
bitstream = self._encrypted_data_as_bitstream()
bitstream.seek(0)
length = bitstream.get_length()
assert length % 8 == 0, \
"The ciphertext data must be a multiple of eight bits in size."
return bitstream.get_base64(length)
def to_file(self, filename, SerializerClass=serialize.XMLSerializer):
"""
Saves this ciphertext to a file.
Arguments:
filename::string -- The path to the file in which to store the
serialized Ciphertext object.
SerializerClass::class --
The class that provides the serialization. XMLSerializer by
default. Must inherit from serialize.BaseSerializer and provide
an adequate serialize_to_file method.
Note that often the same class used to serialize the data must
be used to deserialize it.
(see utilities/serialize.py documentation for more information)
"""
# Create a new serializer object for the Ciphertext structure definition
serializer = SerializerClass(Ciphertext_serialize_structure_definition)
# Generate a serializable data dictionary matching the definition:
data = {
"PloneVoteCiphertext": {
"nbits": str(self.nbits),
"PKFingerprint": self.pk_fingerprint,
"EncryptedData": self._encrypted_data_as_base64()
}
}
# Use the serializer to store the data to file
serializer.serialize_to_file(filename, data)
@classmethod
def from_file(cls, filename, SerializerClass=serialize.XMLSerializer):
"""
Loads an instance of Ciphertext from the given file.
Arguments:
filename::string -- The name of a file containing the ciphertext
in serialized form.
SerializerClass::class --
The class that provides the deserialization. XMLSerializer by
default. Must inherit from serialize.BaseSerializer and provide
an adequate deserialize_from_file method.
Note that often the same class used to serialize the data must
be used to deserialize it.
(see utilities/serialize.py documentation for more information)
Throws:
InvalidPloneVoteCryptoFileError -- If the file is not a valid
PloneVoteCryptoLib stored
ciphertext file.
"""
# Create a new serializer object for the Ciphertext structure definition
serializer = SerializerClass(Ciphertext_serialize_structure_definition)
# Deserialize the Ciphertext instance from file
try:
data = serializer.deserialize_from_file(filename)
except serialize.InvalidSerializeDataError, e:
# Convert the exception to an InvalidPloneVoteCryptoFileError
raise InvalidPloneVoteCryptoFileError(filename,
"File \"%s\" does not contain a valid ciphertext. The " \
"following error occurred while trying to deserialize the " \
"file contents: %s" % (filename, str(e)))
# Get the values from the deserialized data
try:
nbits = int(data["PloneVoteCiphertext"]["nbits"])
except ValueError:
raise InvalidPloneVoteCryptoFileError(filename,
"File \"%s\" does not contain a valid ciphertext. The " \
"stored value for nbits is not a valid (decimal) integer." \
% filename)
fingerprint_str = data["PloneVoteCiphertext"]["PKFingerprint"]
enc_data_str = data["PloneVoteCiphertext"]["EncryptedData"]
# Construct a new Ciphertext object with the given nbits and fingerprint
ciphertext = cls(nbits, fingerprint_str)
# Load the encrypted data
bitstream = BitStream()
bitstream.put_base64(enc_data_str)
bitstream.seek(0)
length = bitstream.get_length()
# number of gamma and delta blocks in the bitstream:
blocks = length / (nbits * 2)
for i in range(0, blocks):
gamma_val = bitstream.get_num(nbits)
delta_val = bitstream.get_num(nbits)
ciphertext.append(gamma_val, delta_val)
# Return the ciphertext
return ciphertext
def new(cls, original_collection, shuffled_collection, mapping):
"""
Constructs a new proof of equivalence between original_collection and
shuffled_collection.
This method should not be used outside of plonevotecryptolib.Mixnet.
Consider using CiphertextCollection.shuffle_with_proof() instead.
The given CiphertextCollectionMapping must be a valid mapping between
original_collection and shuffled_collection.
Arguments:
original_collection::CiphertextCollection --
The original collection to be shuffled.
shuffled_collection::CiphertextCollection --
The shuffled collection resulting from applying mapping to
original_collection.
mapping::CiphertextCollectionMapping --
The mapping between original_collection and shuffled_collection.
Returns:
proof::ShufflingProof --
The zero-knowledge proof of equivalence between
original_collection and shuffled_collection.
Throws:
InvalidCiphertextCollectionMappingError --
If mapping is not a valid mapping between original_collection
and shuffled_collection.
ValueError --
If params.SHUFFLING_PROOF_SECURITY_PARAMETER is within an
invalid range.
"""
# Check that we have a valid mapping between the two collections:
if (not mapping.verify(original_collection, shuffled_collection)):
raise InvalidCiphertextCollectionMappingError( \
"mapping was expected to be a CiphertextCollectionMapping "\
"object representing a valid mapping between "\
"original_collection and shuffled_collection. However, "\
"mapping.verify(original_collection, shuffled_collection) "\
"returns False. A zero-knowledge proof of equivalence "\
"between two shuffled collections cannot be constructed "\
"without first having a valid mapping between them.")
# Get the security parameter P
security_parameter = params.SHUFFLING_PROOF_SECURITY_PARAMETER
# Check that the security parameter is <= 256, since that is the most
# bits of challenge we can currently have. Also check that P is at least 1
if (security_parameter < 1 or security_parameter > 256):
raise ValueError("Security parameter for shuffling proof " \
"(params.SHUFFLING_PROOF_SECURITY_PARAMETER) is out of " \
"range. The security parameter must be between 1 and 256, "\
"its current value is %d. If you have set " \
"CUSTOM_SHUFFLING_PROOF_SECURITY_PARAMETER in the file " \
"params.py, please correct this value or set it to None, " \
"in order for the security parameter to be decided based " \
"on the global SECURITY_LEVEL of plonevotecryptolib. It " \
"is recommended that " \
"CUSTOM_SHUFFLING_PROOF_SECURITY_PARAMETER be always set " \
"to None for deployment operation of plonevotecryptolib." \
% security_parameter)
# Construct a new empty proof
proof = ShufflingProof()
# Populate proof._collections with P random shuffles of
# original_collection. We save each mapping for now in proof._mappings.
# (ie. every mapping in proof._mappings[i] will initially be from the
# original collection into proof._collections[i])
# generate new mappings in parallel
pool = multiprocessing.Pool()
async_params = [original_collection] * security_parameter
generate_mappings_pool = pool.map_async(new_collection_mapping,
async_params)
for new_mapping in generate_mappings_pool.get(99999999):
proof._mappings.append(new_mapping)
proof._collections.append(new_mapping.apply(original_collection))
pool.close()
pool.join()
# Generate the challenge
proof._challenge = \
proof._generate_challenge(original_collection, shuffled_collection)
# Get the challenge as a BitStream for easier manipulation
challenge_bits = BitStream()
challenge_bits.put_hex(proof._challenge)
challenge_bits.seek(0) # back to the beginning of the stream
# For each of the first P bits in the stream
for i in range(0, security_parameter):
## print "Processing challenge bit %d" % i # replace with TaskMonitor API calls
bit = challenge_bits.get_num(1)
if (bit == 0):
# Do nothing.
# proof._mappings[i] is already a mapping from
# original_collection unto proof._collections[i]
pass
elif (bit == 1):
# Change proof._mappings[i] to be a mapping from
# proof._collections[i] unto shuffled_collection, using
# CiphertextCollectionMapping.rebase(...)
# rebase(O->D, O->C_{i}) => C_{i}->D
rebased_mapping = mapping.rebase(proof._mappings[i])
# Replace O->C_{i} with C_{i}->D
proof._mappings[i] = rebased_mapping
else:
assert False, "We took a single bit, its value must be either "\
"0 or 1."
# return the proof object
return proof
def compress_video(self, compress_path, mode="JPEG-1"):
if mode not in ["JPEG-" + str(i)
for i in range(1, 8)] and mode != "JPEG-LS":
print("Invalid mode")
return None
with open(self.file_path, "rb") as stream:
line = stream.readline()
gomby = Golomb(4)
bit_stream = BitStream()
header = self.header[:-1] + " G" + str(
gomby.encoding_parameter) + " M" + mode + "\n"
with open(compress_path, "wb") as file_path:
file_path.write(header.encode())
counter = 0
while True:
start_time = time()
if counter > 2:
break
counter += 1
print("Compressing frame: ", counter)
try:
line = stream.readline()
except ValueError:
print("Finished compressing")
break
line = stream.readline()
self.frame.set_frame(stream)
start = time()
compressed_frame = self.frame.compress_frame(mode)
print("Compressed in ", time() - start)
y = compressed_frame[0]
u = compressed_frame[1]
v = compressed_frame[2]
for x in np.nditer(y):
bit_stream.add_to_bit_array(gomby.encode(int(x)))
#bit_stream.write_allbits(compress_path)
print("Finished compressing Y")
for x in np.nditer(u):
bit_stream.add_to_bit_array(gomby.encode(int(x)))
#bit_stream.write_allbits(compress_path)
print("Finished compressing U")
for x in np.nditer(v):
bit_stream.add_to_bit_array(gomby.encode(int(x)))
bit_stream.write_allbits(compress_path)
print("Finished compressing in", time() - start_time)
bit_stream.close(compress_path)
class BaseRecorder:
bitPacker = None
lock = None
semaphore = None
numObservationBits = None
def __init__(self, bitDepth, numberOfChannels, sampleRate,
widebandFirstStopband, widebandFirstPassband,
widebandSecondPassband, widebandSecondStopband,
passbandAttenuation, stopbandAttenuation, outputFileName,
filter, writeOutput):
self.signal = None
self.bitDepth = bitDepth
self.numberOfChannels = numberOfChannels
self.sampleRate = int(sampleRate)
self.widebandFirstStopband = widebandFirstStopband
self.widebandFirstPassband = widebandFirstPassband
self.widebandSecondPassband = widebandSecondPassband
self.widebandSecondStopband = widebandSecondStopband
self.passbandAttenuation = passbandAttenuation
self.stopbandAttenuation = stopbandAttenuation
self.writeOutput = writeOutput
self.applyFilter = filter
if (self.writeOutput):
self.outputFileName = outputFileName
else:
self.outputFileName = None
if (self.applyFilter):
self.widebandFilter = \
python_initialize_kaiser_filter (
self.widebandFirstStopband,
self.widebandFirstPassband,
self.widebandSecondPassband,
self.widebandSecondStopband,
self.passbandAttenuation,
self.stopbandAttenuation,
int( self.sampleRate )
)
else:
self.widebandFilter = None
def record(self, device):
if ( \
device.hasAppropriateStream ( \
CAHAL_DEVICE_INPUT_STREAM, \
self.numberOfChannels, \
self.bitDepth, \
self.sampleRate \
) \
):
flags = \
CAHAL_AUDIO_FORMAT_FLAGISSIGNEDINTEGER \
| CAHAL_AUDIO_FORMAT_FLAGISPACKED
BaseRecorder.bitPacker = BitPacker()
BaseRecorder.lock = _threading.Lock()
BaseRecorder.semaphore = _threading.Semaphore(0)
self.signal = BitStream(BaseRecorder.bitPacker)
if (
start_recording ( \
device.struct, \
CAHAL_AUDIO_FORMAT_LINEARPCM, \
self.numberOfChannels, \
self.sampleRate, \
self.bitDepth, \
bufferSamples, \
flags \
) \
):
print "Starting recording..."
self.processObservations()
print "Stopping recording..."
cahal_stop_recording()
print "Stopped recording."
else:
print "ERROR: Could not start recording."
else:
print "ERROR: Could not find an appropriate stream."
BaseRecorder.bitPacker = None
BaseRecorder.lock = None
BaseRecorder.semaphore = None
def processObservations(self):
done = False
while (not done):
buffer = None
nBitsToRead = self.getNumberOfBitsToRead()
BaseRecorder.semaphore.acquire(True)
BaseRecorder.lock.acquire(True)
availableData = self.signal.getSize()
BaseRecorder.lock.release()
#print "Available %d, waiting for %d." %( availableData, nBitsToRead )
while (availableData >= nBitsToRead and not done):
BaseRecorder.lock.acquire(True)
buffer = self.signal.read(nBitsToRead)
BaseRecorder.lock.release()
if (None != buffer):
done = self.processBuffer(buffer)
nBitsToRead = self.getNumberOfBitsToRead()
BaseRecorder.lock.acquire(True)
availableData = self.signal.getSize()
BaseRecorder.lock.release()
#print "Available %d, waiting for %d." %( availableData, nBitsToRead )
def getNumberOfBitsToRead(self):
return (0)
def processbuffer(self, buffer):
return (True)
def __del__(self):
if (self.writeOutput):
WAVRecorder.saveSignalToWAV(self.signal, self.outputFileName,
self.numberOfChannels, self.bitDepth,
self.sampleRate)
if (self.signal):
self.signal = None
if (self.widebandFilter):
csignal_destroy_passband_filter(self.widebandFilter)
BaseRecorder.bitPacker = None
BaseRecorder.lock = None
BaseRecorder.semaphore = None
BaseRecorder.numObservationBits = None
def verify(self, original_collection, shuffled_collection):
"""
Verifies that original_collection and shuffled_collection are
equivalent as proven by this ShufflingProof object.
If this method returns true, then we have proof that both collections
contain encryptions of the same collection of plaintexts, save for the
negligible probability (for a correct security parameter configured in
params.py) that the zero-knowledge proof has been faked. Otherwise we
gain no information about the two collections, other than they are not
shown to be equivalent by this particular proof.
ShufflingProof is a zero-knowledge proof: the result of this
verification or the information within the ShufflingProof object for
which two collections pass this verification, provide no information as
to the association of particular ciphertexts in original_collection
with particular ciphertexts of shuffled_collection.
Arguments:
original_collection::CiphertextCollection --
The original collection of ciphertexts.
shuffled_collection::CiphertextCollection --
Another collection for which we wish to know if the current
ShufflingProof object demonstrates equivalence with
original_collection.
Returns:
result::bool -- True if this proof shows both collections to be
equivalent.
False otherwise.
"""
# Get the security parameter P with which the proof was originally
# created. This is reflect in the length of self._collections and
# self._mappings.
assert len(self._collections) == len(self._mappings), \
"The length of the private properties self._collections and " \
"self._mappings of ShufflingProof must always be the same."
security_parameter = len(self._collections)
# Get the security parameter specified in params
minimum_allowed_security_parameter = params.SHUFFLING_PROOF_SECURITY_PARAMETER
# Check that the security parameter is <= 256, since that is the most
# bits of challenge we can currently have. Also check that P is at least 1
if (minimum_allowed_security_parameter < 1
or minimum_allowed_security_parameter > 256):
raise ValueError("Security parameter for shuffling proof " \
"(params.SHUFFLING_PROOF_SECURITY_PARAMETER) is out of " \
"range. The security parameter must be between 1 and 256, "\
"its current value is %d. If you have set " \
"CUSTOM_SHUFFLING_PROOF_SECURITY_PARAMETER in the file " \
"params.py, please correct this value or set it to None, " \
"in order for the security parameter to be decided based " \
"on the global SECURITY_LEVEL of plonevotecryptolib. It " \
"is recommended that " \
"CUSTOM_SHUFFLING_PROOF_SECURITY_PARAMETER be always set " \
"to None for deployment operation of plonevotecryptolib." \
% security_parameter)
# Check that the security parameter for which the proof was generated
# is correct and meets the security standards declared in params.py
if (security_parameter < minimum_allowed_security_parameter
or security_parameter < 1 or security_parameter > 256):
raise InvalidShuffilingProofError("The security parameter for " \
"(which the current proof was created is %d. This is " \
"(either an incorrect value (outside of the [1,256] " \
"(range) or not secure enough to meet the standards set " \
"(in the configuration of params.py (< %d). The proof " \
"(is thus invalid." \
% (security_parameter,
minimum_allowed_security_parameter))
# Generate the challenge
challenge = \
self._generate_challenge(original_collection, shuffled_collection)
# Verify that the challenge corresponds to the stored one
if (challenge != self._challenge):
return False
# Get the challenge as a BitStream for easier manipulation
challenge_bits = BitStream()
challenge_bits.put_hex(challenge)
challenge_bits.seek(0) # back to the beginning of the stream
# For each of the first P bits in the stream
for i in range(0, security_parameter):
bit = challenge_bits.get_num(1)
if (bit == 0):
# verify that self._mapping[i] maps original_collection into
# self._collections[i]
if (not self._mappings[i].verify(original_collection,
self._collections[i])):
return False
elif (bit == 1):
# verify that self._mapping[i] self._collections[i] into
# self._collections[i]
if (not self._mappings[i].verify(self._collections[i],
shuffled_collection)):
return False
else:
assert False, "We took a single bit, its value must be either "\
"0 or 1."
# If we made it so far, the proof is correct
# (each mapping is in accordance to the challenge and valid)
return True
def decrypt_to_bitstream(self, ciphertext, task_monitor=None, force=False):
"""
Decrypts the given ciphertext into a bitstream.
If the bitstream was originally encrypted with PublicKey.encrypt_X(),
then this method returns a bitstream following the format described
in Note 001 of the Ciphertext.py file:
[size (64 bits) | message (size bits) | padding (X bits) ]
Arguments:
ciphertext::Ciphertext -- An encrypted Ciphertext object.
task_monitor::TaskMonitor -- A task monitor for this task.
force:bool -- Set this to true if you wish to force a decryption
attempt, even when the ciphertext's stored public key
fingerprint does not match that of the public key
associated with this private key.
Returns:
bitstream::Bitstream -- A bitstream containing the unencrypted
data.
Throws:
IncompatibleCiphertextError -- The given ciphertext does not appear
to be decryptable with the selected
private key.
"""
# Check that the public key fingerprint stored in the ciphertext
# matches the public key associated with this private key.
if (not force):
if (ciphertext.nbits != self.cryptosystem.get_nbits()):
raise IncompatibleCiphertextError("The given ciphertext is " \
"not decryptable with the selected private key: " \
"incompatible cryptosystem/key sizes.")
if (ciphertext.pk_fingerprint !=
self.public_key.get_fingerprint()):
raise IncompatibleCiphertextError("The given ciphertext is " \
"not decryptable with the selected private key: " \
"public key fingerprint mismatch.")
# We read and decrypt the ciphertext block by block
# See "Handbook of Applied Cryptography" Algorithm 8.18
bitstream = BitStream()
block_size = self.cryptosystem.get_nbits() - 1
prime = self.cryptosystem.get_prime()
key = self._key
# Check if we have a task monitor and register with it
if (task_monitor != None):
# One tick per block
ticks = ciphertext.get_length()
decrypt_task_mon = \
task_monitor.new_subtask("Decrypt data", expected_ticks = ticks)
for gamma, delta in ciphertext:
assert max(gamma, delta) < 2**(block_size + 1), \
"The ciphertext object includes blocks larger than the " \
"expected block size."
m = (pow(gamma, prime - 1 - key, prime) * delta) % prime
bitstream.put_num(m, block_size)
if (task_monitor != None): decrypt_task_mon.tick()
return bitstream
def encrypt_bitstream(self, bitstream, pad_to=None, task_monitor=None):
"""
Encrypts the given bitstream into a ciphertext object.
Arguments:
bitstream::BitStream-- A stream of bits to encrypt
(see BitStream utility class).
pad_to::int -- Minimum size (in bytes) of the resulting
ciphertext. Data will be padded before
encryption to match this size.
task_monitor::TaskMonitor -- A task monitor for this task.
Returns:
ciphertext:Ciphertext -- A ciphertext object encapsulating the
encrypted data.
"""
random = StrongRandom()
## PART 1
# First, format the bitstream as per Ciphertext.py Note 001,
# previous to encryption.
# [size (64 bits) | message (size bits) | padding (X bits) ]
##
formated_bitstream = BitStream()
# The first 64 encode the size of the actual data in bits
SIZE_BLOCK_LENGTH = 64
size_in_bits = bitstream.get_length()
if (size_in_bits >= 2**SIZE_BLOCK_LENGTH):
raise ValueError("The size of the bitstream to encrypt is larger " \
"than 16 Exabits. The current format for " \
"PloneVote ciphertext only allows encrypting a " \
"maximum of 16 Exabits of information.")
formated_bitstream.put_num(size_in_bits, SIZE_BLOCK_LENGTH)
# We then copy the contents of the original bitstream
bitstream.seek(0)
formated_bitstream.put_bitstream_copy(bitstream)
# Finally, we append random data until we reach the desired pad_to
# length
unpadded_length = formated_bitstream.get_length()
if (pad_to != None and (pad_to * 8) > unpadded_length):
full_length = pad_to * 8
else:
full_length = unpadded_length
padding_left = full_length - unpadded_length
while (padding_left > 1024):
padding_bits = random.randint(1, 2**1024)
formated_bitstream.put_num(padding_bits, 1024)
padding_left -= 1024
if (padding_left > 0):
padding_bits = random.randint(1, 2**padding_left)
formated_bitstream.put_num(padding_bits, padding_left)
padding_left = 0
## PART 2
# We encrypt the formated bitsteam using ElGamal into a Ciphertext
# object.
# See "Handbook of Applied Cryptography" Algorithm 8.18
##
# block_size is the size of each block of bits to encrypt
# since we can only encrypt messages in [0, p - 1]
# we should use (nbits - 1) as the block size, where
# 2**(nbits - 1) < p < 2**nbits
block_size = self.cryptosystem.get_nbits() - 1
prime = self.cryptosystem.get_prime()
generator = self.cryptosystem.get_generator()
# We pull data from the bitstream one block at a time and encrypt it
formated_bitstream.seek(0)
ciphertext = \
Ciphertext(self.cryptosystem.get_nbits(), self.get_fingerprint())
plaintext_bits_left = formated_bitstream.get_length()
# Check if we have a task monitor and register with it
if (task_monitor != None):
# We will do two tick()s per block to encrypt: one for generating
# the gamma component of the ciphertext block and another for the
# delta component (those are the two time intensive steps,
# because of exponentiation).
ticks = math.ceil((1.0 * plaintext_bits_left) / block_size) * 2
encrypt_task_mon = \
task_monitor.new_subtask("Encrypt data", expected_ticks = ticks)
while (plaintext_bits_left > 0):
# get next block (message, m, etc) to encrypt
if (plaintext_bits_left >= block_size):
block = formated_bitstream.get_num(block_size)
plaintext_bits_left -= block_size
else:
block = formated_bitstream.get_num(plaintext_bits_left)
# Encrypt as if the stream was filled with random data past its
# end, this avoids introducing a 0's gap during decryption to
# bitstream
displacement = block_size - plaintext_bits_left
block = block << displacement
padding = random.randint(0, 2**displacement - 1)
assert (padding / 2**displacement == 0), \
"padding should be at most displacement bits long"
block = block | padding
plaintext_bits_left = 0
# Select a random integer k, 1 <= k <= p − 2
k = random.randint(1, prime - 2)
# Compute gamma and delta
gamma = pow(generator, k, prime)
if (task_monitor != None): encrypt_task_mon.tick()
delta = (block * pow(self._key, k, prime)) % prime
if (task_monitor != None): encrypt_task_mon.tick()
# Add this encrypted data portion to the ciphertext object
ciphertext.append(gamma, delta)
# return the ciphertext object
return ciphertext
