Inital commit, very buggy!

.gitignore

+# Byte-compiled / optimized / DLL files
+__pycache__/
+*.py[cod]
+
+# C extensions
+*.so
+
+# Distribution / packaging
+.Python
+env/
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+*.egg-info/
+.installed.cfg
+*.egg
+
+# PyInstaller
+#  Usually these files are written by a python script from a template
+#  before PyInstaller builds the exe, so as to inject date/other infos into it.
+*.manifest
+*.spec
+
+# Installer logs
+pip-log.txt
+pip-delete-this-directory.txt
+
+# Unit test / coverage reports
+htmlcov/
+.tox/
+.coverage
+.cache
+nosetests.xml
+coverage.xml
+
+# Translations
+*.mo
+*.pot
+
+# Django stuff:
+*.log
+
+# Sphinx documentation
+docs/_build/
+
+# PyBuilder
+target/
+
+# Config files and keys
+*.yaml
+*.key

README.md

+# OnionBalance
+
+WARNING: THIS IS VERY EXPERIMENTAL, ROUGH CODE. THIS IS NOT READY TO BE USED
+FOR PRODUCTION. IT MAY CONTAIN CRITICAL SECURITY OR PERFORMANCE BUGS.
+
+## Overview
+
+The onion service load balancer allows an operator to distribute requests
+for their onion service to between 1 and 10 separate Tor instances. Each
+Tor instance can run completely independently with no knowledge of any other
+instances.
+
+The load balancer is the only system which needs to store the onion services's private key. As the load balancer handles no hidden service traffic it's
+risk of deanonymisation by traffic analysis attacks is reduced.
+
+## Installation
+
+### Load Balancing Instances
+
+Each load-balancing instance is an onion service configured with a unique
+private key. To minimize the disclosure of information about your onion
+service configuration it is advisable to configure some form of onion service
+authentication.
+
+The individual load balancing instances can use a standard Tor client.
+
+#### Management Server
+
+##### Generate a onion service key
+
+You can use your existing onion service `private_key` or generate a new
+one using OpenSSL.
+
+    $ openssl genrsa -out private_key 1024
+
+##### Encrypt an onion service private key
+
+Your master onion service private key can be protected by encrypting it
+while it is stored on disk. Due to limitation in the underlying pycrypto
+library, only DES-CBC, DES-EDE3-CBC, AES-128-CBC encrypted keys are supported.
+
+    $ openssl rsa -des3 -in private_key -out private_key.enc
+
+##### Configure Tor on the management server
+
+For this tool to work you need a version of Tor with the ability to fetch
+and upload HS descriptors. Until these features are merged into Tor, you can
+use my patched Tor branch.
+
+    $ git clone https://github.com/DonnchaC/tor.git
+    $ git checkout hs-fetch-and-post-cmds
+
+The `docs/torrc` contains a sample Tor config file which is suitable for the
+management server.
+
+##### Install the management server
+
+The code for the onion load balancer can be using git.
+
+    $ git clone https://github.com/DonnchaC/onion-balance.git
+    $ cd onion-balance
+
+The management server requires a number of Python dependencies. These can
+be install using pip.
+
+    $ pip install -r requirements.txt
+
+For onion service descriptor parsing you need a version of stem >= `1.3.0-dev`.
+
+## Configuration
+
+Each load balancing Tor instance is listed by it's unique onion address.
+An optional authentication cookie can also be provided if the back-end onion
+service is using some form of descriptor encryption.
+
+An example config file is provided in `config.yaml.example`.
+
+## Running
+
+Once your load balancing instances are running, you can run the onion load balancer by starting the management server:
+
+    $ python onion-balance/manage.py -f config.yaml
+

config.yaml.example

+# Onion Load Balancer Config File
+# ---
+# Each hidden service key line should be followed be followed by a list of 0
+# or more instances which contain the onion address of the load balancing
+# HS and any authentication data needed to access that HS.
+
+refresh: 600 # How often to poll for updated descriptors
+services:
+    - key: /path/to/private_key # 7s4hxwwifcslrus2.onion
+      instances:
+        - address: o6ff73vmigi4oxka # srv1
+        - address: nkz23ai6qesuwqhc # srv2
+          auth: dCmx3qIvArbil8A0KM4KgQ== # Hidden service authentication key
+    - key: /path/to/private_key.enc # dpkdeys3apjtqydk.onion
+      instances:
+        - address: htbzowpp5cn7wj2u # srv3

doc/torrc

+CookieAuthentication 1
+FetchDirInfoEarly 1
+FetchDirInfoExtraEarly 1
+FetchUselessDescriptors 1

onion-balance/config.py

+# -*- coding: utf-8 -*-
+class Config(object):
+    """
+    Config object to store the global state
+    """
+    def __init__(self):
+        # Configure some defaults
+        self.config = {
+            'replicas': 2,
+            'max_intro_points': 10,
+            'refresh': 10 * 60
+        }
+        # In memory list of hidden services and balancing instances
+        self.hidden_services = []
+
+cfg = Config()

onion-balance/descriptor.py

+# -*- coding: utf-8 -*-
+import hashlib
+import base64
+import textwrap
+import datetime
+
+import Crypto.Util.number
+import stem
+
+import util
+import log
+
+logger = log.get_logger()
+
+
+def generate_hs_descriptor(permanent_key, introduction_point_list=None,
+                           replica=0, timestamp=None):
+    """
+    High-level interface for generating a signed HS descriptor
+    TODO: Allow generation of descriptors for future timeperiod,
+          to help clients with a skewed clock
+    """
+
+    if not timestamp:
+        timestamp = datetime.datetime.utcnow()
+    unix_timestamp = int(timestamp.strftime("%s"))
+
+    permanent_key_block = make_public_key_block(permanent_key)
+    permanent_id = util.calc_permanent_id(permanent_key)
+
+    # Calculate the current secret-id-part for this hidden service
+    time_period = util.get_time_period(unix_timestamp, permanent_id)
+    secret_id_part = util.calc_secret_id_part(time_period, None, replica)
+    descriptor_id = util.calc_descriptor_id(permanent_id, secret_id_part)
+
+    intro_section = make_introduction_points_part(
+        introduction_point_list
+    )
+
+    unsigned_descriptor = generate_hs_descriptor_raw(
+        desc_id_base32=util.base32_encode_str(descriptor_id),
+        permanent_key_block=permanent_key_block,
+        secret_id_part_base32=util.base32_encode_str(secret_id_part),
+        publication_time=util.rounded_timestamp(timestamp),
+        introduction_points_part=intro_section
+    )
+
+    signed_descriptor = sign_descriptor(unsigned_descriptor, permanent_key)
+    return signed_descriptor
+
+
+def generate_hs_descriptor_raw(desc_id_base32, permanent_key_block,
+                               secret_id_part_base32, publication_time,
+                               introduction_points_part):
+    doc = []
+    doc.append("rendezvous-service-descriptor {}".format(desc_id_base32))
+    doc.append("version 2")
+    doc.append("permanent-key")
+    doc.append(permanent_key_block)
+    doc.append("secret-id-part {}".format(secret_id_part_base32))
+    doc.append("publication-time {}".format(publication_time))
+    doc.append("protocol-versions 2,3")
+    doc.append("introduction-points")
+    doc.append(introduction_points_part)
+    doc.append("signature\n")
+
+    unsigned_descriptor = '\n'.join(doc)
+    return unsigned_descriptor
+
+
+def make_introduction_points_part(introduction_point_list):
+    # If not intro points were specified, we should create and empty block
+    if not introduction_point_list:
+        introduction_point_list = []
+    intro = []
+    for intro_point in introduction_point_list:
+        intro.append("introduction-point {}".format(intro_point.identifier))
+        intro.append("ip-address {}".format(intro_point.address))
+        intro.append("onion-port {}".format(intro_point.port))
+        intro.append("onion-key")
+        intro.append(intro_point.onion_key)
+        intro.append("service-key")
+        intro.append(intro_point.service_key)
+
+    intro_section = '\n'.join(intro).encode('utf-8')
+    intro_section_base64 = base64.b64encode(intro_section).decode('utf-8')
+    intro_section_base64 = textwrap.fill(intro_section_base64, 64)
+
+    # Add the header and footer:
+    intro_points_with_headers = '\n'.join([
+        '-----BEGIN MESSAGE-----',
+        intro_section_base64,
+        '-----END MESSAGE-----'])
+    return intro_points_with_headers
+
+
+def make_public_key_block(key):
+    """
+    Get ASN.1 representation of public key, base64 and add headers
+    """
+    asn1_pub = util.get_asn1_sequence(key)
+    pub_base64 = base64.b64encode(asn1_pub).decode('utf-8')
+    pub_base64 = textwrap.fill(pub_base64, 64)
+
+    # Add the header and footer:
+    pub_with_headers = '\n'.join([
+        '-----BEGIN RSA PUBLIC KEY-----',
+        pub_base64,
+        '-----END RSA PUBLIC KEY-----'])
+    return pub_with_headers
+
+
+def sign_digest(digest, private_key):
+    """
+    Sign, base64 encode, wrap and add Tor signature headers
+
+    The message digest is PKCS1 padded without the optional algorithmIdentifier
+    section.
+    """
+
+    digest = util.add_pkcs1_padding(digest)
+    (signature_long, ) = private_key.sign(digest, None)
+    signature_bytes = Crypto.Util.number.long_to_bytes(signature_long, 128)
+    signature_base64 = base64.b64encode(signature_bytes).decode('utf-8')
+    signature_base64 = textwrap.fill(signature_base64, 64)
+
+    # Add the header and footer:
+    signature_with_headers = '\n'.join([
+        '-----BEGIN SIGNATURE-----',
+        signature_base64,
+        '-----END SIGNATURE-----'])
+    return signature_with_headers
+
+
+def sign_descriptor(descriptor, service_key):
+    """'Sign or resign a hidden service descriptor"""
+    TOKEN_HSDESCRIPTOR_SIGNATURE = '\nsignature\n'
+
+    # Remove signature block if it exists
+    if TOKEN_HSDESCRIPTOR_SIGNATURE in descriptor:
+        descriptor = descriptor[:descriptor.find(TOKEN_HSDESCRIPTOR_SIGNATURE)
+                                + len(TOKEN_HSDESCRIPTOR_SIGNATURE)]
+    else:
+        descriptor = descriptor.strip() + TOKEN_HSDESCRIPTOR_SIGNATURE
+
+    descriptor_digest = hashlib.sha1(descriptor.encode('utf-8')).digest()
+    signature_with_headers = sign_digest(descriptor_digest, service_key)
+    return descriptor + signature_with_headers
+
+
+def fetch_descriptor(controller, onion_address, hsdir=None):
+    """
+    Try fetch a HS descriptor from any of the responsible HSDir's"
+    TODO: allow a hsdir to be specified
+    """
+    logger.info("Sending HS descriptor fetch for %s.onion" % onion_address)
+    response = controller.msg("HSFETCH %s" % (onion_address))
+    (response_code, divider, response_content) = response.content()[0]
+    if not response.is_ok():
+        if response_code == "552":
+            raise stem.InvalidRequest(response_code, response_content)
+        else:
+            raise stem.ProtocolError("HSFETCH returned unexpected "
+                                     "response code: %s" % response_code)
+        pass
+
+
+def upload_descriptor(controller, signed_descriptor, hsdirs=None):
+    """
+    Upload descriptor via the Tor control port
+
+    If no HSDir's are specified, Tor will upload to what it thinks are the
+    responsible directories
+    """
+    logger.debug("Sending HS descriptor upload")
+
+    # Provide server fingerprints to control command if HSDirs are specified.
+    if hsdirs:
+        server_args = ' '.join([("SERVER=%s" % hsdir) for hsdir in hsdirs])
+    else:
+        server_args = ""
+
+    response = controller.msg("HSPOST%s\r\n%s\r\n.\r\n" %
+                              (server_args, signed_descriptor))
+
+    (response_code, divider, response_content) = response.content()[0]
+    if not response.is_ok():
+        if response_code == "552":
+            raise stem.InvalidRequest(response_code, response_content)
+        else:
+            raise stem.ProtocolError("+HSPOST returned unexpected response "
+                                     "code: %s" % response_code)

onion-balance/eventhandler.py

+# -*- coding: utf-8 -*-
+import stem
+
+import log
+import config
+
+logger = log.get_logger()
+
+
+class EventHandler(object):
+
+    """
+    Handles asynchronous Tor events.
+    """
+
+    def __init__(self, controller):
+
+        self.controller = controller
+
+    def new_desc(self, desc_event):
+        """
+        Parse HS_DESC response events
+        """
+        logger.debug("Received new HS_DESC event: %s" %
+                     str(desc_event))
+
+    def new_desc_content(self, desc_content_event):
+        """
+        Parse HS_DESC_CONTENT response events for descriptor content
+
+        Update the HS instance object with the data from the new descriptor.
+        """
+        logger.debug("Received new HS_DESC_CONTENT event for %s" %
+                     desc_content_event.address)
+
+        # Make sure the descriptor is not empty
+        descriptor_text = str(desc_content_event.descriptor).encode('utf-8')
+        if len(descriptor_text) < 5:
+            logger.debug("Empty descriptor received for %s" %
+                         desc_content_event.address)
+            return
+
+        # Find the HS instance for this descriptor
+        for service in config.cfg.hidden_services:
+            for instance in service.instances:
+                if instance.onion_address == desc_content_event.address:
+                    instance.update_descriptor(descriptor_text)
+                    return
+
+    def new_event(self, event):
+        """
+        Dispatches new Tor controller events to the appropriate handlers.
+        """
+        if isinstance(event, stem.response.events.HSDescEvent):
+            self.new_desc(event)
+
+        elif isinstance(event, stem.response.events.HSDescContentEvent):
+            self.new_desc_content(event)
+
+        else:
+            logger.warning("Received unexpected event %s." % str(event))

onion-balance/hiddenservice.py

+# -*- coding: utf-8 -*-
+import datetime
+import random
+import time
+
+import Crypto.PublicKey.RSA
+import stem.descriptor.hidden_service_descriptor
+
+import descriptor
+import util
+import log
+import config
+
+logger = log.get_logger()
+
+
+def fetch_all_descriptors(controller):
+    """
+    Try fetch fresh descriptors for all HS instances
+    """
+    logger.info("Running periodic descriptor fetch")
+
+    # Clear Tor descriptor cache before fetches by sending NEWNYM
+    controller.signal(stem.control.Signal.NEWNYM)
+    time.sleep(5)
+
+    for service in config.cfg.hidden_services:
+        for instance in service.instances:
+                instance.fetch_descriptor()
+
+
+def publish_all_descriptors():
+    """
+    Called periodically to upload new super-descriptors if needed
+    """
+    logger.info("Running periodic descriptor publish")
+    for service in config.cfg.hidden_services:
+        service.publish()
+
+
+class HiddenService(object):
+    """
+    HiddenService represents a front-facing hidden service which should
+    be load-balanced.
+    """
+
+    def __init__(self, controller, service_key=None, instances=None):
+        """
+        Initialise a HiddenService object.
+        """
+        self.controller = controller
+
+        # Service key must be a valid PyCrypto RSA key object
+        if not isinstance(service_key, Crypto.PublicKey.RSA._RSAobj):
+            raise ValueError("Service key is not a valid RSA object")
+        else:
+            self.service_key = service_key
+
+        # List of load balancing Instances for this hidden service
+        if not instances:
+            instances = []
+        self.instances = instances
+
+        self.onion_address = util.calc_onion_address(self.service_key)
+        self.last_uploaded = None
+
+    def _intro_points_modified(self):
+        """
+        Check if the introduction point set has changed since last
+        publish.
+        """
+        for instance in self.instances:
+            if instance.changed_since_published:
+                return True
+
+        # No introduction points have changed
+        return False
+
+    def _descriptor_expiring(self):
+        """
+        Check if the last uploaded super descriptor is expiring (> 1
+        hour old).
+        """
+        if not self.last_uploaded:
+            # No descriptor uploaded yet, we should publish.
+            return True
+
+        descriptor_age = (datetime.datetime.utcnow() - self.last_uploaded)
+        if (descriptor_age.total_seconds() > 60 * 60):
+            return True
+
+        return False
+
+    def _get_combined_introduction_points(self):
+        """
+        Choose set of introduction points from all fresh descriptors
+
+        TODO: There are probably better algorithms for choosing which
+        introduction points to include. If we have more than
+        `max_intro_points` introduction points, we will need to exclude
+        some.  It probably sensible to prefer IPs which are new and
+        haven't been included in any previous descriptors. Clients with
+        an old descriptor will continue trying previously published IPs
+        if they still work.
+        """
+
+        combined_intro_points = []
+        for instance in self.instances:
+
+            if not instance.last_fetched:
+                logger.debug("No descriptor fetched for instance '%s' yet. "
+                             "Skipping!" % instance.onion_address)
+                continue
+
+            # Check if the intro points are too old
+            intro_age = datetime.datetime.utcnow() - instance.last_fetched
+            if intro_age.total_seconds() > 60 * 60:
+                logger.info("Our introduction points for instance '%s' "
+                            "are too old. Skipping!" % instance.onion_address)
+                continue
+
+            # Our IP's are recent enough, include them
+            instance.changed_since_published = False
+            combined_intro_points.extend(instance.introduction_points)
+
+        # Choose up to `max_intro_points` IPs from the combined set
+        max_introduction_points = min(
+            len(combined_intro_points),
+            config.cfg.config.get("max_intro_points")
+        )
+
+        choosen_intro_points = random.sample(combined_intro_points,
+                                             max_introduction_points)
+        # Shuffle IP's to try reveal less information about which
+        # instances are online and have introduction points included.
+        random.shuffle(choosen_intro_points)
+
+        logger.debug("Selected %d IPs (of %d) for service '%s'" %
+                     (len(choosen_intro_points), len(combined_intro_points),
+                      self.onion_address))
+
+        return choosen_intro_points
+
+    def _get_signed_descriptor(self, replica=0):
+        """
+        Generate a signed HS descriptor for this hidden service
+        """
+
+        # Select a set of introduction points from this HS's load
+        # balancing instances.
+        introduction_points = self._get_combined_introduction_points()
+
+        signed_descriptor = descriptor.generate_hs_descriptor(
+            self.service_key,
+            introduction_point_list=introduction_points,
+            replica=replica
+        )
+        return signed_descriptor
+
+    def _upload_descriptor(self):
+        """
+        Create, sign and upload a super-descriptors for this HS
+
+        TODO: If the descriptor ID is changing soon, upload to current
+              and upcoming set's of HSDirs.
+        """
+        for replica in range(0, config.cfg.config.get("replicas")):
+            signed_descriptor = self._get_signed_descriptor(replica=replica)
+            descriptor.upload_descriptor(self.controller, signed_descriptor)
+
+        self.last_uploaded = datetime.datetime.utcnow()
+
+    def publish(self, force=False):
+        """
+        Publish descriptor if have new IP's or if descriptor has expired
+        """
+
+        if (    self._intro_points_modified() or
+                self._descriptor_expiring() or
+                force):
+            logger.info("Publishing new descriptor for '%s'" %
+                        self.onion_address)
+
+            self._upload_descriptor()
+
+
+class Instance(object):
+    """
+    Instance represents a back-end load balancing hidden service.
+    """
+
+    def __init__(self, controller, onion_address, authentication_cookie):
+        """
+        Initialise an Instance object.
+        """
+        self.controller = controller
+        self.onion_address = onion_address
+        self.authentication_cookie = authentication_cookie
+
+        self.introduction_points = []
+        self.last_fetched = None
+        self.changed_since_published = False
+
+    def fetch_descriptor(self):
+        """
+        Try fetch a fresh descriptor for this back-end HS instance.
+        """
+        logger.debug("Trying to fetch a descriptor of instance '%s'" %
+                     self.onion_address)
+        return descriptor.fetch_descriptor(self.controller, self.onion_address)
+
+    def update_descriptor(self, descriptor_content):
+        """
+        Update introduction points when a new HS descriptor is received
+
+        Parse the descriptor content and update the set of introduction
+        points for this HS instance.
+        """
+
+        logger.info("Received a descriptor for %s" % self.onion_address)
+
+        self.last_fetched = datetime.datetime.utcnow()
+
+        # Parse and store this descriptors introduction points.
+        parsed_descriptor = stem.descriptor.hidden_service_descriptor.\
+            HiddenServiceDescriptor(descriptor_content)
+
+        # Parse the introduction point list, decrypting if necessary
+        introduction_points = parsed_descriptor.introduction_points(
+            authentication_cookie=self.authentication_cookie)
+
+        # If the new intro point set is different, flag this HS instance
+        # as modified.
+        if introduction_points != self.introduction_points:
+            logger.info("New IPs found for '%s'" % self.onion_address)
+            self.changed_since_publish = True
+            self.introduction_points = introduction_points
+
+        else:
+            logger.info("IPs for '%s' matched the cached set" %
+                        self.onion_address)

onion-balance/log.py

+# -*- coding: utf-8 -*-
+import logging
+
+handler = logging.StreamHandler()
+handler.setFormatter(logging.Formatter(fmt="%(asctime)s [%(levelname)s]: "
+                                           "%(message)s"))
+
+logger = logging.getLogger("onion-load-balancer")
+logger.addHandler(handler)
+logger.setLevel(logging.DEBUG)
+
+
+def get_logger():
+    """
+    Returns a logger.
+    """
+    return logger

onion-balance/manager.py

+# -*- coding: utf-8 -*-
+"""
+Load balance a hidden service across multiple (remote) Tor instances by
+create a hidden service descriptor containing introduction points from
+each instance.
+"""
+import sys
+import argparse
+import time
+import os
+import logging
+
+# import Crypto.PublicKeyl
+import stem
+from stem.control import Controller, EventType
+import yaml
+import schedule
+
+import log
+import util
+import config
+import hiddenservice
+import eventhandler
+
+
+logger = log.get_logger()
+
+
+def parse_cmd_args():
+    """
+    Parses and returns command line arguments.
+    """
+
+    parser = argparse.ArgumentParser(
+        description="%s distributes the requests for a Tor hidden services "
+        "across multiple (remote) Tor instances." % sys.argv[0])
+
+    parser.add_argument("-i", "--ip", type=str, default="127.0.0.1",
+                        help="Tor controller IP address")
+
+    parser.add_argument("-p", "--port", type=int, default=9051,
+                        help="Tor controller port")
+
+    parser.add_argument("-c", "--config", type=str,
+                        default="config.yaml", help="Config file")
+
+    parser.add_argument("-v", "--verbosity", type=str, default="info",
+                        help="Minimum verbosity level for logging.  Available "
+                             "in ascending order: debug, info, warning, "
+                             "error, critical).  The default is info.")
+
+    return parser.parse_args()
+
+
+def parse_config_file(config_file):
+    """
+    Parse config file contain load balancing node configuration
+    """
+    if os.path.exists(config_file):
+        with open(config_file, 'r') as handle:
+            config_data = yaml.load(handle.read())
+            logger.info("Loaded the config file '%s'" % config_file)
+    else:
+        logger.error("The specified config file does not exist (%s)" %
+                     config_file)
+        sys.exit(1)
+
+    return config_data
+
+
+def main():
+    """
+    Entry point when invoked over the command line.
+    """
+    args = parse_cmd_args()
+    config.cfg.config.update(parse_config_file(args.config))
+
+    logger.setLevel(logging.__dict__[args.verbosity.upper()])
+
+    # Create a connection to the Tor control port
+    controller = Controller.from_port(address=args.ip, port=args.port)
+    try:
+        controller.authenticate()
+    except stem.connection.AuthenticationFailure as exc:
+        logger.error("Unable to authenticate to Tor control port: %s"
+                     % exc)
+        sys.exit(1)
+    else:
+        logger.debug("Successfully connected to the Tor control port")
+
+    # Load the keys and configuration for each hidden service
+    for service in config.cfg.config.get("services"):
+        service_key = util.key_decrypt_prompt(service.get("key"))
+        if not service_key:
+            logger.error("Private key could not be imported (%s)" %
+                         args.key)
+            sys.exit(0)
+        else:
+            # Successfully import the private key
+            onion_address = util.calc_onion_address(service_key)
+            logger.debug("Loaded private key for service '%s'" %
+                         onion_address)
+
+        # Parse the load balancing instances for this hidden service
+        instance_config = service.get("instances", [])
+        if not instance_config:
+            logger.error("No load balancing hidden service "
+                         "specified for %s" % onion_address)
+            sys.exit(1)
+        else:
+            instances = []
+            for instance in instance_config:
+                instances.append(hiddenservice.Instance(
+                    controller=controller,
+                    onion_address=instance.get("address"),
+                    authentication_cookie=instance.get("auth")
+                ))
+
+            logger.info("Loaded {} balancing services for {}".format(
+                        len(instances), onion_address))
+
+        config.cfg.hidden_services.append(hiddenservice.HiddenService(
+            controller=controller,
+            service_key=service_key,
+            instances=instances
+        ))
+    # Finished parsing all the config file.
+
+    handler = eventhandler.EventHandler(controller)
+    controller.add_event_listener(handler.new_event,
+                                  EventType.HS_DESC,
+                                  EventType.HS_DESC_CONTENT)
+
+    # Run initial fetch of HS instance descriptors
+    hiddenservice.fetch_all_descriptors(controller)
+    time.sleep(15)
+    hiddenservice.publish_all_descriptors()
+
+    # Schedule descriptor fetch and upload events
+    schedule.every(config.cfg.config.get('refresh')).seconds.do(
+        hiddenservice.fetch_all_descriptors, controller)
+    schedule.every(config.cfg.config.get('refresh')).seconds.do(
+        hiddenservice.publish_all_descriptors)
+
+    # Begin main loop to poll for HS descriptors
+    try:
+        while True:
+            schedule.run_pending()
+            time.sleep(1)
+    except KeyboardInterrupt:
+        logger.info("Stopping descriptor uploads")
+
+    return 0
+
+if __name__ == "__main__":
+    exit(main())

onion-balance/util.py

+# -*- coding: utf-8 -*-
+import hashlib
+import struct
+import datetime
+import getpass
+import base64
+import binascii
+
+# import Crypto.Util
+import Crypto.PublicKey
+
+
+def add_pkcs1_padding(message):
+    """Add PKCS#1 padding to **message**."""
+    padding = b''
+    typeinfo = b'\x00\x01'
+    separator = b'\x00'
+    for x in range(125 - len(message)):
+        padding += b'\xFF'
+    PKCS1paddedMessage = typeinfo + padding + separator + message
+    assert len(PKCS1paddedMessage) == 128
+    return PKCS1paddedMessage
+
+
+def get_asn1_sequence(rsa_key):
+    seq = Crypto.Util.asn1.DerSequence()
+    seq.append(rsa_key.n)
+    seq.append(rsa_key.e)
+    asn1_seq = seq.encode()
+    return asn1_seq
+
+
+def calc_key_digest(rsa_key):
+    """Calculate the SHA1 digest of an RSA key"""
+    return hashlib.sha1(get_asn1_sequence(rsa_key)).digest()
+
+
+def calc_permanent_id(rsa_key):
+    return calc_key_digest(rsa_key)[:10]
+
+
+def calc_onion_address(rsa_key):
+    return base64.b32encode(calc_permanent_id(rsa_key)).decode().lower()
+
+
+def calc_descriptor_id(permanent_id, secret_id_part):
+    return hashlib.sha1(permanent_id + secret_id_part).digest()
+
+
+def get_time_period(time, permanent_id):
+    """
+    time-period = (current-time + permanent-id-byte * 86400 / 256) / 86400
+    """
+    permanent_id_byte = int(struct.unpack('B', permanent_id[0:1])[0])
+    return int((time + permanent_id_byte * 86400 / 256) / 86400)
+
+
+def calc_secret_id_part(time_period, descriptor_cookie, replica):
+    """
+    secret-id-part = H(time-period | descriptor-cookie | replica)
+    """
+    secret_id_part = hashlib.sha1()
+    secret_id_part.update(struct.pack('>I', time_period)[:4])
+    if descriptor_cookie:
+        secret_id_part.update(descriptor_cookie)
+    secret_id_part.update(binascii.unhexlify('{0:02X}'.format(replica)))
+    return secret_id_part.digest()
+
+
+def rounded_timestamp(timestamp=None):
+    """
+    Create timestamp rounded down to the nearest hour
+    """
+    if not timestamp:
+        timestamp = datetime.datetime.utcnow()
+    timestamp = timestamp.replace(minute=0, second=0, microsecond=0)
+    return timestamp.strftime('%Y-%m-%d %H:%M:%S')
+
+
+def base32_encode_str(bytes):
+    """
+    Encode bytes as lowercase base32 string
+    """
+    return base64.b32encode(bytes).lower().decode('utf-8')
+
+
+def key_decrypt_prompt(key_file, retries=3):
+    """
+    Try open an PEM encrypted private key, propmpting the user for a
+    passphrase if required.
+    """
+
+    for retries in range(0, retries):
+        key_passphrase = None
+        with open(key_file, 'r') as handle:
+            pem_key = handle.read()
+
+            if "Proc-Type: 4,ENCRYPTED" in pem_key:  # Key looks encrypted
+                key_passphrase = getpass.getpass(
+                    "Enter the password for the private key (%s): " % key_file)
+            try:
+                permanent_key = Crypto.PublicKey.RSA.importKey(
+                    pem_key, passphrase=key_passphrase)
+            except ValueError:
+                # Key not decrypted correctly, prompt for passphrase again
+                continue
+            else:
+                return permanent_key
+
+    # No private key was imported
+    raise ValueError("Could not import RSA key")

requirements.txt

+PyYAML==3.11
+pycrypto==2.6.1
+schedule==0.3.1
+stem==1.3.0-dev