class VerifyCrawler(threading.Thread):
''' This is an active thread that is responsible for serving all
messages that come in from the keylogger. It simply strips
them out of the socket and forwards them along to the logger
actor via a message dictionary.
'''
def __init__(self, vid, logServer, keyServer, keyMgr):
''' Constructor that stores the log server information.
'''
threading.Thread.__init__(self)
self.id = vid
self.logServer = logServer
self.keyServer = keyServer
self.running = True
# Build the encryption module
self.keyMgr = keyMgr
self.encryptionModule = EncryptionModule(keyMgr) # pass along the key manager reference
# Generate the used entry bucket
self.usedBin = {}
self.MAX_TRIES = 10 # This can (and should) be configured by experimentation.
# Configure the logger
logFile = 'abls.log'
logging.basicConfig(filename=logFile,level=logging.DEBUG)
def run(self):
''' The main thread loop for this verifier.
'''
# Create the shim
self.logShim = DBShim(self.logServer, self.keyMgr)
self.keyShim = DBShim(self.keyServer, self.keyMgr)
# Run the crawler loop indefinitely...
while self.running:
logging.debug("Verifier " + str(self.id) + " is trying to grab a user session to verify.")
(userId, sessionId) = self.selectRow()
# Check to see if we found some valid data...
if (userId != -1 and sessionId != -1):
# Decrypt the user/session ID to get the original data
userCT = userId.decode("hex")
sessionCT = sessionId.decode("hex")
key = hashlib.sha256(self.keyMgr.getMasterKey() + "log").digest()
cipher = AES.new(key, AES.MODE_ECB)
userPT = cipher.decrypt(userCT)
sessionPT = cipher.decrypt(sessionCT)
# Query the keys from the database
logging.debug("Verifying: " + str(userPT) + " - " + str(sessionPT))
valueMap = {"userId" : userPT, "sessionId" : sessionPT}
epochKey = self.keyShim.executeMultiQuery("initialEpochKey", valueMap, ["userId", "sessionId"])
key1 = epochKey[0]["key"]
entityKey = self.keyShim.executeMultiQuery("initialEntityKey", valueMap, ["userId", "sessionId"])
key2 = entityKey[0]["key"]
# Decrypt the keys using the 'verifier' policy
logging.debug("Trying to decrypt")
sk = self.encryptionModule.generateUserKey(['VERIFIER'])
k1 = self.encryptionModule.decrypt(sk, key1)[1] # [1] to pull out plaintext, [0] is T/F flag
k2 = self.encryptionModule.decrypt(sk, key2)[1] # [1] to pull out plaintext, [0] is T/F flag
# Query the last digest from the database
logging.debug("Decryption successful - continue with the verification process")
entityDigest = self.logShim.executeMultiQuery("entity", valueMap, ["userId", "sessionId"])
digest = entityDigest[len(entityDigest) - 1]["digest"]
# Query for the log now.
valueMap = {"userId" : userId, "sessionId" : sessionId}
logResult = self.logShim.executeMultiQuery("log", valueMap, [])
log = {}
userId = int(userPT)
sessionId = int(sessionPT)
log[(userId, sessionId)] = []
for i in range(0, len(logResult)):
log[(userId, sessionId)].append([userId, sessionId, logResult[i]["epochId"], logResult[i]["message"], logResult[i]["xhash"], logResult[i]["yhash"]])
# Verify the data extracted from the database...
self.strongestVerify(userId, sessionId, log, k1, k2, digest, Logger.Logger.EPOCH_WINDOW_SIZE)
# Don't hog the system resources
time.sleep(15)
def selectRow(self):
''' Randomly select a row from the database to check with strong verification.
'''
userId = sessionId = 0
foundNewRow = False
tries = 0
while not foundNewRow:
result = self.logShim.randomQuery("log")
if (len(result) > 0):
userId = result[0]["userId"]
sessionId = result[0]["sessionId"]
if not ((userId, sessionId) in self.usedBin):
self.usedBin[(userId, sessionId)] = 0
foundNewRow = True
# Upgrade all the instances for
for key in self.usedBin.keys():
self.usedBin[key] = self.usedBin[key] + 1
# See if we ran past the try cap
tries = tries + 1
if (tries >= self.MAX_TRIES):
tk1, tk2, maxNum = 0, 0, 0
for (k1, k2) in self.usedBin.keys():
if (self.usedBin[(k1, k2)] > maxNum):
maxNum = self.usedBin[(k1, k2)]
tk1 = -1
tk2 = -1
del self.usedBin[(tk1, tk2)]
userId = tk1
sessionId = tk2
foundNewRow = True # we're going to retry a previous row
else:
userId = sessionId = -1
foundNewRow = True
return (userId, sessionId)
def strongestVerify(self, userId, sessionId, log, epochKey, entityKey, lastDigest, EPOCH_WINDOW_SIZE = Logger.Logger.EPOCH_WINDOW_SIZE):
''' Walks the log chain and epoch chain for verification, and computes the
entity digests at every epoch cycle for comparison to check with
the end result. Not publicly verifiable, and requires the initial epoch and entity keys.
'''
ctChain = []
sha3 = Keccak.Keccak()
# It is assumed that we would get this initial key from the trusted server...
# This verification scheme is not possible without the epoch key...
lastEpochDigest = hmac.new(epochKey, "0", hashlib.sha512).hexdigest()
# Check to see if we even have anything to verify
if not ((userId, sessionId) in log):
return None
else:
# Handle the base of the chain
first = log[(userId, sessionId)][0]
firstPayload = str(userId) + str(sessionId) + str(0) + str(first[3]) + str(0)
# Check the hash chain first
xi = sha3.Keccak((len(bytes(firstPayload)), firstPayload.encode("hex")))
computedV = sha3.Keccak((len(xi), xi))
assert(xi == first[4])
# Check the epoch chain next
yi = hmac.new(epochKey, lastEpochDigest.encode("hex") + first[4].encode("hex"), hashlib.sha512).hexdigest()
assert(yi == first[5])
# Compute the first part of the entity chain now
lastEntityDigest = hmac.new(entityKey, xi, hashlib.sha512).hexdigest()
entityKey = hmac.new(entityKey, "some constant value", hashlib.sha512).hexdigest()
# Append the first message.
ctChain.append(first[3])
# Walk the chain and make sure we can verify it...
for i in range(1, len(log[(userId, sessionId)])):
first = log[(userId, sessionId)][i]
# Store the message
firstMessage = first[3] # the message
ctChain.append(firstMessage)
# The other data...
currentHash = first[4] # the hash
previousHash = log[(userId, sessionId)][i - 1][4]
# Verify that the first entry is correct
firstPayload = str(userId) + str(0) + str(i) + str(firstMessage) + str(previousHash)
firstComputedHash = sha3.Keccak((len(bytes(firstPayload)), firstPayload.encode("hex")))
assert(currentHash == firstComputedHash)
# Check the epoch chain to see if we need to cycle
if ((i % EPOCH_WINDOW_SIZE) == 0):
# Update the epoch key
currKey = epochKey
newKey = sha3.Keccak((len(bytes(currKey)), currKey.encode("hex")))
epochKey = newKey
# Pull the last hash block
length = len(log[(userId, sessionId)])
lastHash = log[(userId, sessionId)][i - 1][4]
# Form the epoch block hash payload
payload = str(lastEpochDigest) + str(lastHash)
lastEpochDigest = hmac.new(newKey, payload, hashlib.sha512).hexdigest()
# Compute the epoch chain value
yi = hmac.new(epochKey, lastEpochDigest.encode("hex") + first[4].encode("hex"), hashlib.sha512).hexdigest()
assert(yi == first[5])
# Compute the first part of the entity chain now
lastEntityDigest = hmac.new(entityKey, first[4], hashlib.sha512).hexdigest()
entityKey = hmac.new(entityKey, "some constant value", hashlib.sha512).hexdigest()
assert(lastEntityDigest == lastDigest)
logging.debug("Verification result:" + str(lastEntityDigest == lastDigest))
return ctChain
def weakVerify(self, userId, sessionId, log, epochKey, entityKey, EPOCH_WINDOW_SIZE):
''' Only walks the log chain for verification.
'''
ctChain = []
# Make sure we have something to verify first...
if not ((userId, sessionId) in log):
return None
else:
# Handle the base of the chain
first = log[(userId, sessionId)][0]
firstPayload = str(userId) + str(sessionId) + str(0) + str(first[3]) + str(0)
digest = sha3.Keccak((len(bytes(firstPayload)), firstPayload.encode("hex")))
assert(digest == first[4])
# Append the first message.
ctChain.append(first[3])
# Walk the chain and make sure we can verify it...
for i in range(1, len(log[(userId, sessionId)])):
first = log[(userId, sessionId)][i]
# Store the message
firstMessage = first[3] # the message
ctChain.append(firstMessage)
# The other data...
currentHash = first[4] # the hash
previousHash = log[(userId, sessionId)][i - 1][4]
# Verify that the first entry is correct
firstPayload = str(userId) + str(0) + str(i) + str(firstMessage) + str(previousHash)
firstComputedHash = sha3.Keccak((len(bytes(firstPayload)), firstPayload.encode("hex")))
assert(currentHash == firstComputedHash)
return ctChain
# Test before sharing
(mk1, pk1) = enc1.getValues()
(mk2, pk2) = enc2.getValues()
print("Master keys (before sharing)")
print(objectToBytes(mk1, PairingGroup('SS512')) == objectToBytes(mk2, PairingGroup('SS512')))
print("Public keys (before sharing)")
print(objectToBytes(pk1, PairingGroup('SS512')) == objectToBytes(pk2, PairingGroup('SS512')))
# Test before sharing the keys
ct1 = enc1.encrypt(msg, policy)
ct2 = enc2.encrypt(msg, policy)
sk1 = enc1.generateUserKey(attrs) # takes a list of attributes (in caps?)
sk2 = enc2.generateUserKey(attrs) # takes a list of attributes (in caps?)
#print(enc1.decrypt(sk1, ct2)[1])
print(enc1.decrypt(sk2, ct2)[1])
# Dipslay master keys
(mk1, pk1) = enc1.getValues()
(mk2, pk2) = enc2.getValues()
enc2.set(mk1, pk1)
(mk2, pk2) = enc2.getValues()
print("Master keys (after sharing)")
print(objectToBytes(mk1, PairingGroup('SS512')) == objectToBytes(mk2, PairingGroup('SS512')))
print("Public keys (after sharing)")
print(objectToBytes(pk1, PairingGroup('SS512')) == objectToBytes(pk2, PairingGroup('SS512')))
ct1 = enc1.encrypt(msg, policy)
ct2 = enc2.encrypt(msg, policy)
sk1 = enc1.generateUserKey(attrs) # takes a list of attributes (in caps?)
sk2 = enc2.generateUserKey(attrs) # takes a list of attributes (in caps?)
