PyBitmessage-2021-04-27/src/class_singleWorker.py

"""
Thread for performing PoW
"""
# pylint: disable=protected-access,too-many-branches,too-many-statements
# pylint: disable=no-self-use,too-many-lines,too-many-locals

from __future__ import division

import hashlib
import time
from binascii import hexlify, unhexlify
from struct import pack

import defaults
import helper_db
import helper_msgcoding
import helper_random
import helper_sql
import highlevelcrypto
import l10n
import proofofwork
import protocol
import queues
import shared
import state
import tr
from addresses import (
    calculateInventoryHash, decodeAddress, decodeVarint, encodeVarint
)
from bmconfigparser import BMConfigParser
from helper_sql import sqlExecute, sqlQuery
from inventory import Inventory
from network import knownnodes, StoppableThread


def sizeof_fmt(num, suffix='h/s'):
    """Format hashes per seconds nicely (SI prefix)"""

    for unit in ['', 'k', 'M', 'G', 'T', 'P', 'E', 'Z']:
        if abs(num) < 1000.0:
            return "%3.1f%s%s" % (num, unit, suffix)
        num /= 1024.0
    return "%.1f%s%s" % (num, 'Yi', suffix)


class singleWorker(StoppableThread):
    """Thread for performing PoW"""

    def __init__(self):
        super(singleWorker, self).__init__(name="singleWorker")
        proofofwork.init()

    def stopThread(self):
        """Signal through the queue that the thread should be stopped"""

        try:
            queues.workerQueue.put(("stopThread", "data"))
        except:
            pass
        super(singleWorker, self).stopThread()

    def run(self):
        # pylint: disable=attribute-defined-outside-init

        while not helper_sql.sql_ready.wait(1.0) and state.shutdown == 0:
            self.stop.wait(1.0)
        if state.shutdown > 0:
            return

        # Initialize the neededPubkeys dictionary.
        queryreturn = sqlQuery(
            '''SELECT DISTINCT toaddress FROM sent'''
            ''' WHERE (status='awaitingpubkey' AND folder='sent')''')
        for row in queryreturn:
            toAddress, = row
            # toStatus
            _, toAddressVersionNumber, toStreamNumber, toRipe = \
                decodeAddress(toAddress)
            if toAddressVersionNumber <= 3:
                state.neededPubkeys[toAddress] = 0
            elif toAddressVersionNumber >= 4:
                doubleHashOfAddressData = hashlib.sha512(hashlib.sha512(
                    encodeVarint(toAddressVersionNumber) +
                    encodeVarint(toStreamNumber) + toRipe
                ).digest()).digest()
                # Note that this is the first half of the sha512 hash.
                privEncryptionKey = doubleHashOfAddressData[:32]
                tag = doubleHashOfAddressData[32:]
                # We'll need this for when we receive a pubkey reply:
                # it will be encrypted and we'll need to decrypt it.
                state.neededPubkeys[tag] = (
                    toAddress,
                    highlevelcrypto.makeCryptor(
                        hexlify(privEncryptionKey))
                )

        # Initialize the state.ackdataForWhichImWatching data structure
        queryreturn = sqlQuery(
            '''SELECT ackdata FROM sent WHERE status = 'msgsent' AND folder = 'sent' ''')
        for row in queryreturn:
            ackdata, = row
            self.logger.info('Watching for ackdata %s', hexlify(ackdata))
            state.ackdataForWhichImWatching[ackdata] = 0

        # Fix legacy (headerless) watched ackdata to include header
        for oldack in state.ackdataForWhichImWatching:
            if len(oldack) == 32:
                # attach legacy header, always constant (msg/1/1)
                newack = '\x00\x00\x00\x02\x01\x01' + oldack
                state.ackdataForWhichImWatching[newack] = 0
                sqlExecute(
                    '''UPDATE sent SET ackdata=? WHERE ackdata=? AND folder = 'sent' ''',
                    newack, oldack
                )
                del state.ackdataForWhichImWatching[oldack]

        # For the case if user deleted knownnodes
        # but is still having onionpeer objects in inventory
        if not knownnodes.knownNodesActual:
            for item in Inventory().by_type_and_tag(protocol.OBJECT_ONIONPEER):
                queues.objectProcessorQueue.put((
                    protocol.OBJECT_ONIONPEER, item.payload
                ))
                # FIXME: should also delete from inventory

        # give some time for the GUI to start
        # before we start on existing POW tasks.
        self.stop.wait(10)

        if state.shutdown:
            return

        # just in case there are any pending tasks for msg
        # messages that have yet to be sent.
        queues.workerQueue.put(('sendmessage', ''))
        # just in case there are any tasks for Broadcasts
        # that have yet to be sent.
        queues.workerQueue.put(('sendbroadcast', ''))

        # send onionpeer object
        queues.workerQueue.put(('sendOnionPeerObj', ''))

        while state.shutdown == 0:
            self.busy = 0
            command, data = queues.workerQueue.get()
            self.busy = 1
            if command == 'sendmessage':
                try:
                    self.sendMsg()
                except:
                    pass
            elif command == 'sendbroadcast':
                try:
                    self.sendBroadcast()
                except:
                    pass
            elif command == 'doPOWForMyV2Pubkey':
                try:
                    self.doPOWForMyV2Pubkey(data)
                except:
                    pass
            elif command == 'sendOutOrStoreMyV3Pubkey':
                try:
                    self.sendOutOrStoreMyV3Pubkey(data)
                except:
                    pass
            elif command == 'sendOutOrStoreMyV4Pubkey':
                try:
                    self.sendOutOrStoreMyV4Pubkey(data)
                except:
                    pass
            elif command == 'sendOnionPeerObj':
                try:
                    self.sendOnionPeerObj(data)
                except:
                    pass
            elif command == 'resetPoW':
                try:
                    proofofwork.resetPoW()
                except:
                    pass
            elif command == 'stopThread':
                self.busy = 0
                return
            else:
                self.logger.error(
                    'Probable programming error: The command sent'
                    ' to the workerThread is weird. It is: %s\n',
                    command
                )

            queues.workerQueue.task_done()
        self.logger.info("Quitting...")

    def _getKeysForAddress(self, address):
        privSigningKeyBase58 = BMConfigParser().get(
            address, 'privsigningkey')
        privEncryptionKeyBase58 = BMConfigParser().get(
            address, 'privencryptionkey')

        privSigningKeyHex = hexlify(shared.decodeWalletImportFormat(
            privSigningKeyBase58))
        privEncryptionKeyHex = hexlify(shared.decodeWalletImportFormat(
            privEncryptionKeyBase58))

        # The \x04 on the beginning of the public keys are not sent.
        # This way there is only one acceptable way to encode
        # and send a public key.
        pubSigningKey = unhexlify(highlevelcrypto.privToPub(
            privSigningKeyHex))[1:]
        pubEncryptionKey = unhexlify(highlevelcrypto.privToPub(
            privEncryptionKeyHex))[1:]

        return privSigningKeyHex, privEncryptionKeyHex, \
            pubSigningKey, pubEncryptionKey

    def _doPOWDefaults(self, payload, TTL,
                       log_prefix='',
                       log_time=False):
        target = 2 ** 64 / (
            defaults.networkDefaultProofOfWorkNonceTrialsPerByte * (
                len(payload) + 8 +
                defaults.networkDefaultPayloadLengthExtraBytes + ((
                    TTL * (
                        len(payload) + 8 +
                        defaults.networkDefaultPayloadLengthExtraBytes
                    )) / (2 ** 16))
            ))
        initialHash = hashlib.sha512(payload).digest()
        self.logger.info(
            '%s Doing proof of work... TTL set to %s', log_prefix, TTL)
        if log_time:
            start_time = time.time()
        trialValue, nonce = proofofwork.run(target, initialHash)
        self.logger.info(
            '%s Found proof of work %s Nonce: %s',
            log_prefix, trialValue, nonce
        )
        try:
            delta = time.time() - start_time
            self.logger.info(
                'PoW took %.1f seconds, speed %s.',
                delta, sizeof_fmt(nonce / delta)
            )
        except:  # NameError
            pass
        payload = pack('>Q', nonce) + payload
        return payload

    def doPOWForMyV2Pubkey(self, adressHash):
        """ This function also broadcasts out the pubkey
        message once it is done with the POW"""
        # Look up my stream number based on my address hash
        myAddress = shared.myAddressesByHash[adressHash]
        # status
        _, addressVersionNumber, streamNumber, adressHash = (
            decodeAddress(myAddress))

        # 28 days from now plus or minus five minutes
        TTL = int(28 * 24 * 60 * 60 + helper_random.randomrandrange(-300, 300))
        embeddedTime = int(time.time() + TTL)
        payload = pack('>Q', (embeddedTime))
        payload += '\x00\x00\x00\x01'  # object type: pubkey
        payload += encodeVarint(addressVersionNumber)  # Address version number
        payload += encodeVarint(streamNumber)
        # bitfield of features supported by me (see the wiki).
        payload += protocol.getBitfield(myAddress)

        try:
            # privSigningKeyHex, privEncryptionKeyHex
            _, _, pubSigningKey, pubEncryptionKey = \
                self._getKeysForAddress(myAddress)
        except Exception as err:
            self.logger.error(
                'Error within doPOWForMyV2Pubkey. Could not read'
                ' the keys from the keys.dat file for a requested'
                ' address. %s\n', err
            )
            return

        payload += pubSigningKey + pubEncryptionKey

        # Do the POW for this pubkey message
        payload = self._doPOWDefaults(
            payload, TTL, log_prefix='(For pubkey message)')

        inventoryHash = calculateInventoryHash(payload)
        objectType = 1
        Inventory()[inventoryHash] = (
            objectType, streamNumber, payload, embeddedTime, '')

        self.logger.info(
            'broadcasting inv with hash: %s', hexlify(inventoryHash))

        queues.invQueue.put((streamNumber, inventoryHash))
        queues.UISignalQueue.put(('updateStatusBar', ''))
        try:
            BMConfigParser().set(
                myAddress, 'lastpubkeysendtime', str(int(time.time())))
            BMConfigParser().save()
        except:
            # The user deleted the address out of the keys.dat file
            # before this finished.
            pass

    def sendOutOrStoreMyV3Pubkey(self, adressHash):
        """
        If this isn't a chan address, this function assembles the pubkey data, does the necessary POW and sends it out.
        If it *is* a chan then it assembles the pubkey and stores is in the pubkey table so that we can send messages
        to "ourselves".
        """
        try:
            myAddress = shared.myAddressesByHash[adressHash]
        except:
            # The address has been deleted.
            return
        if BMConfigParser().safeGetBoolean(myAddress, 'chan'):
            self.logger.info('This is a chan address. Not sending pubkey.')
            return
        _, addressVersionNumber, streamNumber, adressHash = decodeAddress(
            myAddress)

        # 28 days from now plus or minus five minutes
        TTL = int(28 * 24 * 60 * 60 + helper_random.randomrandrange(-300, 300))
        embeddedTime = int(time.time() + TTL)

        # signedTimeForProtocolV2 = embeddedTime - TTL
        # According to the protocol specification, the expiresTime
        # along with the pubkey information is signed. But to be
        # backwards compatible during the upgrade period, we shall sign
        # not the expiresTime but rather the current time. There must be
        # precisely a 28 day difference between the two. After the upgrade
        # period we'll switch to signing the whole payload with the
        # expiresTime time.

        payload = pack('>Q', (embeddedTime))
        payload += '\x00\x00\x00\x01'  # object type: pubkey
        payload += encodeVarint(addressVersionNumber)  # Address version number
        payload += encodeVarint(streamNumber)
        # bitfield of features supported by me (see the wiki).
        payload += protocol.getBitfield(myAddress)

        try:
            # , privEncryptionKeyHex
            privSigningKeyHex, _, pubSigningKey, pubEncryptionKey = \
                self._getKeysForAddress(myAddress)
        except Exception as err:
            self.logger.error(
                'Error within sendOutOrStoreMyV3Pubkey. Could not read'
                ' the keys from the keys.dat file for a requested'
                ' address. %s\n', err
            )
            return

        payload += pubSigningKey + pubEncryptionKey

        payload += encodeVarint(BMConfigParser().getint(
            myAddress, 'noncetrialsperbyte'))
        payload += encodeVarint(BMConfigParser().getint(
            myAddress, 'payloadlengthextrabytes'))

        signature = highlevelcrypto.sign(payload, privSigningKeyHex)
        payload += encodeVarint(len(signature))
        payload += signature

        # Do the POW for this pubkey message
        payload = self._doPOWDefaults(
            payload, TTL, log_prefix='(For pubkey message)')

        inventoryHash = calculateInventoryHash(payload)
        objectType = 1
        Inventory()[inventoryHash] = (
            objectType, streamNumber, payload, embeddedTime, '')

        self.logger.info(
            'broadcasting inv with hash: %s', hexlify(inventoryHash))

        queues.invQueue.put((streamNumber, inventoryHash))
        queues.UISignalQueue.put(('updateStatusBar', ''))
        try:
            BMConfigParser().set(
                myAddress, 'lastpubkeysendtime', str(int(time.time())))
            BMConfigParser().save()
        except:
            # The user deleted the address out of the keys.dat file
            # before this finished.
            pass

    def sendOutOrStoreMyV4Pubkey(self, myAddress):
        """
        It doesn't send directly anymore. It put is to a queue for another thread to send at an appropriate time,
        whereas in the past it directly appended it to the outgoing buffer, I think. Same with all the other methods in
        this class.
        """
        if not BMConfigParser().has_section(myAddress):
            # The address has been deleted.
            return
        if shared.BMConfigParser().safeGetBoolean(myAddress, 'chan'):
            self.logger.info('This is a chan address. Not sending pubkey.')
            return
        _, addressVersionNumber, streamNumber, addressHash = decodeAddress(
            myAddress)

        # 28 days from now plus or minus five minutes
        TTL = int(28 * 24 * 60 * 60 + helper_random.randomrandrange(-300, 300))
        embeddedTime = int(time.time() + TTL)
        payload = pack('>Q', (embeddedTime))
        payload += '\x00\x00\x00\x01'  # object type: pubkey
        payload += encodeVarint(addressVersionNumber)  # Address version number
        payload += encodeVarint(streamNumber)
        dataToEncrypt = protocol.getBitfield(myAddress)

        try:
            # , privEncryptionKeyHex
            privSigningKeyHex, _, pubSigningKey, pubEncryptionKey = \
                self._getKeysForAddress(myAddress)
        except Exception as err:
            self.logger.error(
                'Error within sendOutOrStoreMyV4Pubkey. Could not read'
                ' the keys from the keys.dat file for a requested'
                ' address. %s\n', err
            )
            return

        dataToEncrypt += pubSigningKey + pubEncryptionKey

        dataToEncrypt += encodeVarint(BMConfigParser().getint(
            myAddress, 'noncetrialsperbyte'))
        dataToEncrypt += encodeVarint(BMConfigParser().getint(
            myAddress, 'payloadlengthextrabytes'))

        # When we encrypt, we'll use a hash of the data
        # contained in an address as a decryption key. This way
        # in order to read the public keys in a pubkey message,
        # a node must know the address first. We'll also tag,
        # unencrypted, the pubkey with part of the hash so that nodes
        # know which pubkey object to try to decrypt
        # when they want to send a message.
        doubleHashOfAddressData = hashlib.sha512(hashlib.sha512(
            encodeVarint(addressVersionNumber) +
            encodeVarint(streamNumber) + addressHash
        ).digest()).digest()
        payload += doubleHashOfAddressData[32:]  # the tag
        signature = highlevelcrypto.sign(
            payload + dataToEncrypt, privSigningKeyHex
        )
        dataToEncrypt += encodeVarint(len(signature))
        dataToEncrypt += signature

        privEncryptionKey = doubleHashOfAddressData[:32]
        pubEncryptionKey = highlevelcrypto.pointMult(privEncryptionKey)
        payload += highlevelcrypto.encrypt(
            dataToEncrypt, hexlify(pubEncryptionKey))

        # Do the POW for this pubkey message
        payload = self._doPOWDefaults(
            payload, TTL, log_prefix='(For pubkey message)')

        inventoryHash = calculateInventoryHash(payload)
        objectType = 1
        Inventory()[inventoryHash] = (
            objectType, streamNumber, payload, embeddedTime,
            doubleHashOfAddressData[32:]
        )

        self.logger.info(
            'broadcasting inv with hash: %s', hexlify(inventoryHash))

        queues.invQueue.put((streamNumber, inventoryHash))
        queues.UISignalQueue.put(('updateStatusBar', ''))
        try:
            BMConfigParser().set(
                myAddress, 'lastpubkeysendtime', str(int(time.time())))
            BMConfigParser().save()
        except Exception as err:
            self.logger.error(
                'Error: Couldn\'t add the lastpubkeysendtime'
                ' to the keys.dat file. Error message: %s', err
            )

    def sendOnionPeerObj(self, peer=None):
        """Send onionpeer object representing peer"""
        if not peer:  # find own onionhostname
            for peer in state.ownAddresses:
                if peer.host.endswith('.onion'):
                    break
            else:
                return
        TTL = int(7 * 24 * 60 * 60 + helper_random.randomrandrange(-300, 300))
        embeddedTime = int(time.time() + TTL)
        streamNumber = 1  # Don't know yet what should be here
        objectType = protocol.OBJECT_ONIONPEER
        # FIXME: ideally the objectPayload should be signed
        objectPayload = encodeVarint(peer.port) + protocol.encodeHost(peer.host)
        tag = calculateInventoryHash(objectPayload)

        if Inventory().by_type_and_tag(objectType, tag):
            return  # not expired

        payload = pack('>Q', embeddedTime)
        payload += pack('>I', objectType)
        payload += encodeVarint(2 if len(peer.host) == 22 else 3)
        payload += encodeVarint(streamNumber)
        payload += objectPayload

        payload = self._doPOWDefaults(
            payload, TTL, log_prefix='(For onionpeer object)')

        inventoryHash = calculateInventoryHash(payload)
        Inventory()[inventoryHash] = (
            objectType, streamNumber, buffer(payload),
            embeddedTime, buffer(tag)
        )
        self.logger.info(
            'sending inv (within sendOnionPeerObj function) for object: %s',
            hexlify(inventoryHash))
        queues.invQueue.put((streamNumber, inventoryHash))

    def sendBroadcast(self):
        """Send a broadcast-type object (assemble the object, perform PoW and put it to the inv announcement queue)"""
        # Reset just in case
        sqlExecute(
            '''UPDATE sent SET status='broadcastqueued' '''

            '''WHERE status = 'doingbroadcastpow' AND folder = 'sent' ''')
        queryreturn = sqlQuery(
            '''SELECT fromaddress, subject, message, '''
            ''' ackdata, ttl, encodingtype FROM sent '''
            ''' WHERE status=? and folder='sent' ''', 'broadcastqueued')

        for row in queryreturn:
            fromaddress, subject, body, ackdata, TTL, encoding = row
            # status
            _, addressVersionNumber, streamNumber, ripe = \
                decodeAddress(fromaddress)
            if addressVersionNumber <= 1:
                self.logger.error(
                    'Error: In the singleWorker thread, the '
                    ' sendBroadcast function doesn\'t understand'
                    ' the address version.\n')
                return
            # We need to convert our private keys to public keys in order
            # to include them.
            try:
                # , privEncryptionKeyHex
                privSigningKeyHex, _, pubSigningKey, pubEncryptionKey = \
                    self._getKeysForAddress(fromaddress)
            except:
                queues.UISignalQueue.put((
                    'updateSentItemStatusByAckdata', (
                        ackdata,
                        tr._translate(
                            "MainWindow",
                            "Error! Could not find sender address"
                            " (your address) in the keys.dat file."))
                ))
                continue

            if not sqlExecute(
                    '''UPDATE sent SET status='doingbroadcastpow' '''
                    ''' WHERE ackdata=? AND status='broadcastqueued' '''
                    ''' AND folder='sent' ''',
                    ackdata):
                continue

            # At this time these pubkeys are 65 bytes long
            # because they include the encoding byte which we won't
            # be sending in the broadcast message.
            # pubSigningKey = \
            #     highlevelcrypto.privToPub(privSigningKeyHex).decode('hex')

            if TTL > 28 * 24 * 60 * 60:
                TTL = 28 * 24 * 60 * 60
            if TTL < 60 * 60:
                TTL = 60 * 60
            # add some randomness to the TTL
            TTL = int(TTL + helper_random.randomrandrange(-300, 300))
            embeddedTime = int(time.time() + TTL)
            payload = pack('>Q', embeddedTime)
            payload += '\x00\x00\x00\x03'  # object type: broadcast

            if addressVersionNumber <= 3:
                payload += encodeVarint(4)  # broadcast version
            else:
                payload += encodeVarint(5)  # broadcast version

            payload += encodeVarint(streamNumber)
            if addressVersionNumber >= 4:
                doubleHashOfAddressData = hashlib.sha512(hashlib.sha512(
                    encodeVarint(addressVersionNumber) +
                    encodeVarint(streamNumber) + ripe
                ).digest()).digest()
                tag = doubleHashOfAddressData[32:]
                payload += tag
            else:
                tag = ''

            dataToEncrypt = encodeVarint(addressVersionNumber)
            dataToEncrypt += encodeVarint(streamNumber)
            # behavior bitfield
            dataToEncrypt += protocol.getBitfield(fromaddress)
            dataToEncrypt += pubSigningKey + pubEncryptionKey
            if addressVersionNumber >= 3:
                dataToEncrypt += encodeVarint(BMConfigParser().getint(
                    fromaddress, 'noncetrialsperbyte'))
                dataToEncrypt += encodeVarint(BMConfigParser().getint(
                    fromaddress, 'payloadlengthextrabytes'))
            # message encoding type
            dataToEncrypt += encodeVarint(encoding)
            encodedMessage = helper_msgcoding.MsgEncode(
                {"subject": subject, "body": body}, encoding)
            dataToEncrypt += encodeVarint(encodedMessage.length)
            dataToEncrypt += encodedMessage.data
            dataToSign = payload + dataToEncrypt

            signature = highlevelcrypto.sign(
                dataToSign, privSigningKeyHex)
            dataToEncrypt += encodeVarint(len(signature))
            dataToEncrypt += signature

            # Encrypt the broadcast with the information
            # contained in the broadcaster's address.
            # Anyone who knows the address can generate
            # the private encryption key to decrypt the broadcast.
            # This provides virtually no privacy; its purpose is to keep
            # questionable and illegal content from flowing through the
            # Internet connections and being stored on the disk of 3rd parties.
            if addressVersionNumber <= 3:
                privEncryptionKey = hashlib.sha512(
                    encodeVarint(addressVersionNumber) +
                    encodeVarint(streamNumber) + ripe
                ).digest()[:32]
            else:
                privEncryptionKey = doubleHashOfAddressData[:32]

            pubEncryptionKey = highlevelcrypto.pointMult(privEncryptionKey)
            payload += highlevelcrypto.encrypt(
                dataToEncrypt, hexlify(pubEncryptionKey))

            queues.UISignalQueue.put((
                'updateSentItemStatusByAckdata', (
                    ackdata,
                    tr._translate(
                        "MainWindow",
                        "Doing work necessary to send broadcast..."))
            ))
            payload = self._doPOWDefaults(
                payload, TTL, log_prefix='(For broadcast message)')

            # Sanity check. The payload size should never be larger
            # than 256 KiB. There should be checks elsewhere in the code
            # to not let the user try to send a message this large
            # until we implement message continuation.
            if len(payload) > 2 ** 18:  # 256 KiB
                self.logger.critical(
                    'This broadcast object is too large to send.'
                    ' This should never happen. Object size: %s',
                    len(payload)
                )
                continue

            inventoryHash = calculateInventoryHash(payload)
            objectType = 3
            Inventory()[inventoryHash] = (
                objectType, streamNumber, payload, embeddedTime, tag)
            self.logger.info(
                'sending inv (within sendBroadcast function)'
                ' for object: %s',
                hexlify(inventoryHash)
            )
            queues.invQueue.put((streamNumber, inventoryHash))

            queues.UISignalQueue.put((
                'updateSentItemStatusByAckdata', (
                    ackdata,
                    tr._translate(
                        "MainWindow",
                        "Broadcast sent on %1"
                    ).arg(l10n.formatTimestamp()))
            ))

            # Update the status of the message in the 'sent' table to have
            # a 'broadcastsent' status
            sqlExecute(
                '''UPDATE sent SET msgid=?, status=?, lastactiontime=? '''
                ''' WHERE ackdata=? AND folder='sent' ''',
                inventoryHash, 'broadcastsent', int(time.time()), ackdata
            )

    def sendMsg(self):
        """Send a message-type object (assemble the object, perform PoW and put it to the inv announcement queue)"""
        # pylint: disable=too-many-nested-blocks
        # Reset just in case
        sqlExecute(
            '''UPDATE sent SET status='msgqueued' '''
            ''' WHERE status IN ('doingpubkeypow', 'doingmsgpow') '''
            ''' AND folder='sent' ''')
        queryreturn = sqlQuery(
            '''SELECT toaddress, fromaddress, subject, message, '''
            ''' ackdata, status, ttl, retrynumber, encodingtype FROM '''
            ''' sent WHERE (status='msgqueued' or status='forcepow') '''
            ''' and folder='sent' ''')
        # while we have a msg that needs some work
        for row in queryreturn:
            toaddress, fromaddress, subject, message, \
                ackdata, status, TTL, retryNumber, encoding = row
            # toStatus
            _, toAddressVersionNumber, toStreamNumber, toRipe = \
                decodeAddress(toaddress)
            # fromStatus, , ,fromRipe
            _, fromAddressVersionNumber, fromStreamNumber, _ = \
                decodeAddress(fromaddress)

            # We may or may not already have the pubkey
            # for this toAddress. Let's check.
            if status == 'forcepow':
                # if the status of this msg is 'forcepow'
                # then clearly we have the pubkey already
                # because the user could not have overridden the message
                # about the POW being too difficult without knowing
                # the required difficulty.
                pass
            elif status == 'doingmsgpow':
                # We wouldn't have set the status to doingmsgpow
                # if we didn't already have the pubkey so let's assume
                # that we have it.
                pass
            # If we are sending a message to ourselves or a chan
            # then we won't need an entry in the pubkeys table;
            # we can calculate the needed pubkey using the private keys
            # in our keys.dat file.
            elif BMConfigParser().has_section(toaddress):
                if not sqlExecute(
                    '''UPDATE sent SET status='doingmsgpow' '''
                    ''' WHERE toaddress=? AND status='msgqueued' AND folder='sent' ''',
                    toaddress
                ):
                    continue
                status = 'doingmsgpow'
            elif status == 'msgqueued':
                # Let's see if we already have the pubkey in our pubkeys table
                queryreturn = sqlQuery(
                    '''SELECT address FROM pubkeys WHERE address=?''',
                    toaddress
                )
                # If we have the needed pubkey in the pubkey table already,
                if queryreturn != []:
                    # set the status of this msg to doingmsgpow
                    if not sqlExecute(
                        '''UPDATE sent SET status='doingmsgpow' '''
                        ''' WHERE toaddress=? AND status='msgqueued' AND folder='sent' ''',
                        toaddress
                    ):
                        continue
                    status = 'doingmsgpow'
                    # mark the pubkey as 'usedpersonally' so that
                    # we don't delete it later. If the pubkey version
                    # is >= 4 then usedpersonally will already be set
                    # to yes because we'll only ever have
                    # usedpersonally v4 pubkeys in the pubkeys table.
                    sqlExecute(
                        '''UPDATE pubkeys SET usedpersonally='yes' '''
                        ''' WHERE address=?''',
                        toaddress
                    )
                # We don't have the needed pubkey in the pubkeys table already.
                else:
                    if toAddressVersionNumber <= 3:
                        toTag = ''
                    else:
                        toTag = hashlib.sha512(hashlib.sha512(
                            encodeVarint(toAddressVersionNumber) +
                            encodeVarint(toStreamNumber) + toRipe
                        ).digest()).digest()[32:]
                    if toaddress in state.neededPubkeys or \
                            toTag in state.neededPubkeys:
                        # We already sent a request for the pubkey
                        sqlExecute(
                            '''UPDATE sent SET status='awaitingpubkey', '''
                            ''' sleeptill=? WHERE toaddress=? '''
                            ''' AND status='msgqueued' ''',
                            int(time.time()) + 2.5 * 24 * 60 * 60,
                            toaddress
                        )
                        queues.UISignalQueue.put((
                            'updateSentItemStatusByToAddress', (
                                toaddress,
                                tr._translate(
                                    "MainWindow",
                                    "Encryption key was requested earlier."))
                        ))
                        # on with the next msg on which we can do some work
                        continue
                    else:
                        # We have not yet sent a request for the pubkey
                        needToRequestPubkey = True
                        # If we are trying to send to address
                        # version >= 4 then the needed pubkey might be
                        # encrypted in the inventory.
                        # If we have it we'll need to decrypt it
                        # and put it in the pubkeys table.

                        # The decryptAndCheckPubkeyPayload function
                        # expects that the shared.neededPubkeys dictionary
                        # already contains the toAddress and cryptor
                        # object associated with the tag for this toAddress.
                        if toAddressVersionNumber >= 4:
                            doubleHashOfToAddressData = hashlib.sha512(
                                hashlib.sha512(
                                    encodeVarint(toAddressVersionNumber) + encodeVarint(toStreamNumber) + toRipe
                                ).digest()
                            ).digest()
                            # The first half of the sha512 hash.
                            privEncryptionKey = doubleHashOfToAddressData[:32]
                            # The second half of the sha512 hash.
                            tag = doubleHashOfToAddressData[32:]
                            state.neededPubkeys[tag] = (
                                toaddress,
                                highlevelcrypto.makeCryptor(
                                    hexlify(privEncryptionKey))
                            )

                            for value in Inventory().by_type_and_tag(1, toTag):
                                # if valid, this function also puts it
                                # in the pubkeys table.
                                if protocol.decryptAndCheckPubkeyPayload(
                                        value.payload, toaddress
                                ) == 'successful':
                                    needToRequestPubkey = False
                                    sqlExecute(
                                        '''UPDATE sent SET '''
                                        ''' status='doingmsgpow', '''
                                        ''' retrynumber=0 WHERE '''
                                        ''' toaddress=? AND '''
                                        ''' (status='msgqueued' or '''
                                        ''' status='awaitingpubkey' or '''
                                        ''' status='doingpubkeypow') AND '''
                                        ''' folder='sent' ''',
                                        toaddress)
                                    del state.neededPubkeys[tag]
                                    break
                                # else:
                                # There was something wrong with this
                                # pubkey object even though it had
                                # the correct tag- almost certainly
                                # because of malicious behavior or
                                # a badly programmed client. If there are
                                # any other pubkeys in our inventory
                                # with the correct tag then we'll try
                                # to decrypt those.
                        if needToRequestPubkey:
                            sqlExecute(
                                '''UPDATE sent SET '''
                                ''' status='doingpubkeypow' WHERE '''
                                ''' toaddress=? AND status='msgqueued' AND folder='sent' ''',
                                toaddress
                            )
                            queues.UISignalQueue.put((
                                'updateSentItemStatusByToAddress', (
                                    toaddress,
                                    tr._translate(
                                        "MainWindow",
                                        "Sending a request for the"
                                        " recipient\'s encryption key."))
                            ))
                            self.requestPubKey(toaddress)
                            # on with the next msg on which we can do some work
                            continue

            # At this point we know that we have the necessary pubkey
            # in the pubkeys table.

            TTL *= 2**retryNumber
            if TTL > 28 * 24 * 60 * 60:
                TTL = 28 * 24 * 60 * 60
            # add some randomness to the TTL
            TTL = int(TTL + helper_random.randomrandrange(-300, 300))
            embeddedTime = int(time.time() + TTL)

            # if we aren't sending this to ourselves or a chan
            if not BMConfigParser().has_section(toaddress):
                state.ackdataForWhichImWatching[ackdata] = 0
                queues.UISignalQueue.put((
                    'updateSentItemStatusByAckdata', (
                        ackdata,
                        tr._translate(
                            "MainWindow",
                            "Looking up the receiver\'s public key"))
                ))
                self.logger.info('Sending a message.')
                self.logger.debug(
                    'First 150 characters of message: %s',
                    repr(message[:150])
                )

                # Let us fetch the recipient's public key out of
                # our database. If the required proof of work difficulty
                # is too hard then we'll abort.
                queryreturn = sqlQuery(
                    'SELECT transmitdata FROM pubkeys WHERE address=?',
                    toaddress)
                for row in queryreturn:  # pylint: disable=redefined-outer-name
                    pubkeyPayload, = row

                # The pubkey message is stored with the following items
                # all appended:
                #    -address version
                #    -stream number
                #    -behavior bitfield
                #    -pub signing key
                #    -pub encryption key
                #    -nonce trials per byte (if address version is >= 3)
                #    -length extra bytes (if address version is >= 3)

                # to bypass the address version whose length is definitely 1
                readPosition = 1
                _, streamNumberLength = decodeVarint(
                    pubkeyPayload[readPosition:readPosition + 10])
                readPosition += streamNumberLength
                behaviorBitfield = pubkeyPayload[readPosition:readPosition + 4]
                # Mobile users may ask us to include their address's
                # RIPE hash on a message unencrypted. Before we actually
                # do it the sending human must check a box
                # in the settings menu to allow it.

                # if receiver is a mobile device who expects that their
                # address RIPE is included unencrypted on the front of
                # the message..
                if protocol.isBitSetWithinBitfield(behaviorBitfield, 30):
                    # if we are Not willing to include the receiver's
                    # RIPE hash on the message..
                    if not shared.BMConfigParser().safeGetBoolean(
                            'bitmessagesettings', 'willinglysendtomobile'
                    ):
                        self.logger.info(
                            'The receiver is a mobile user but the'
                            ' sender (you) has not selected that you'
                            ' are willing to send to mobiles. Aborting'
                            ' send.'
                        )
                        queues.UISignalQueue.put((
                            'updateSentItemStatusByAckdata', (
                                ackdata,
                                tr._translate(
                                    "MainWindow",
                                    "Problem: Destination is a mobile"
                                    " device who requests that the"
                                    " destination be included in the"
                                    " message but this is disallowed in"
                                    " your settings.  %1"
                                ).arg(l10n.formatTimestamp()))
                        ))
                        # if the human changes their setting and then
                        # sends another message or restarts their client,
                        # this one will send at that time.
                        continue
                readPosition += 4  # to bypass the bitfield of behaviors
                # We don't use this key for anything here.
                # pubSigningKeyBase256 =
                # pubkeyPayload[readPosition:readPosition+64]
                readPosition += 64
                pubEncryptionKeyBase256 = pubkeyPayload[
                    readPosition:readPosition + 64]
                readPosition += 64

                # Let us fetch the amount of work required by the recipient.
                if toAddressVersionNumber == 2:
                    requiredAverageProofOfWorkNonceTrialsPerByte = \
                        defaults.networkDefaultProofOfWorkNonceTrialsPerByte
                    requiredPayloadLengthExtraBytes = \
                        defaults.networkDefaultPayloadLengthExtraBytes
                    queues.UISignalQueue.put((
                        'updateSentItemStatusByAckdata', (
                            ackdata,
                            tr._translate(
                                "MainWindow",
                                "Doing work necessary to send message.\n"
                                "There is no required difficulty for"
                                " version 2 addresses like this."))
                    ))
                elif toAddressVersionNumber >= 3:
                    requiredAverageProofOfWorkNonceTrialsPerByte, \
                        varintLength = decodeVarint(
                            pubkeyPayload[readPosition:readPosition + 10])
                    readPosition += varintLength
                    requiredPayloadLengthExtraBytes, varintLength = \
                        decodeVarint(
                            pubkeyPayload[readPosition:readPosition + 10])
                    readPosition += varintLength
                    # We still have to meet a minimum POW difficulty
                    # regardless of what they say is allowed in order
                    # to get our message to propagate through the network.
                    if requiredAverageProofOfWorkNonceTrialsPerByte < \
                            defaults.networkDefaultProofOfWorkNonceTrialsPerByte:
                        requiredAverageProofOfWorkNonceTrialsPerByte = \
                            defaults.networkDefaultProofOfWorkNonceTrialsPerByte
                    if requiredPayloadLengthExtraBytes < \
                            defaults.networkDefaultPayloadLengthExtraBytes:
                        requiredPayloadLengthExtraBytes = \
                            defaults.networkDefaultPayloadLengthExtraBytes
                    self.logger.debug(
                        'Using averageProofOfWorkNonceTrialsPerByte: %s'
                        ' and payloadLengthExtraBytes: %s.',
                        requiredAverageProofOfWorkNonceTrialsPerByte,
                        requiredPayloadLengthExtraBytes
                    )

                    queues.UISignalQueue.put(
                        (
                            'updateSentItemStatusByAckdata',
                            (
                                ackdata,
                                tr._translate(
                                    "MainWindow",
                                    "Doing work necessary to send message.\n"
                                    "Receiver\'s required difficulty: %1"
                                    " and %2"
                                ).arg(
                                    str(
                                        float(requiredAverageProofOfWorkNonceTrialsPerByte) /
                                        defaults.networkDefaultProofOfWorkNonceTrialsPerByte
                                    )
                                ).arg(
                                    str(
                                        float(requiredPayloadLengthExtraBytes) /
                                        defaults.networkDefaultPayloadLengthExtraBytes
                                    )
                                )
                            )
                        )
                    )

                    if status != 'forcepow':
                        maxacceptablenoncetrialsperbyte = BMConfigParser().getint(
                            'bitmessagesettings', 'maxacceptablenoncetrialsperbyte')
                        maxacceptablepayloadlengthextrabytes = BMConfigParser().getint(
                            'bitmessagesettings', 'maxacceptablepayloadlengthextrabytes')
                        cond1 = maxacceptablenoncetrialsperbyte and \
                            requiredAverageProofOfWorkNonceTrialsPerByte > maxacceptablenoncetrialsperbyte
                        cond2 = maxacceptablepayloadlengthextrabytes and \
                            requiredPayloadLengthExtraBytes > maxacceptablepayloadlengthextrabytes

                        if cond1 or cond2:
                            # The demanded difficulty is more than
                            # we are willing to do.
                            sqlExecute(
                                '''UPDATE sent SET status='toodifficult' '''
                                ''' WHERE ackdata=? AND folder='sent' ''',
                                ackdata)
                            queues.UISignalQueue.put((
                                'updateSentItemStatusByAckdata', (
                                    ackdata,
                                    tr._translate(
                                        "MainWindow",
                                        "Problem: The work demanded by"
                                        " the recipient (%1 and %2) is"
                                        " more difficult than you are"
                                        " willing to do. %3"
                                    ).arg(str(float(requiredAverageProofOfWorkNonceTrialsPerByte) /
                                              defaults.networkDefaultProofOfWorkNonceTrialsPerByte)).arg(
                                                  str(float(requiredPayloadLengthExtraBytes) /
                                                      defaults.networkDefaultPayloadLengthExtraBytes)).arg(
                                                          l10n.formatTimestamp()))))
                            continue
            else:  # if we are sending a message to ourselves or a chan..
                self.logger.info('Sending a message.')
                self.logger.debug(
                    'First 150 characters of message: %r', message[:150])
                behaviorBitfield = protocol.getBitfield(fromaddress)

                try:
                    privEncryptionKeyBase58 = BMConfigParser().get(
                        toaddress, 'privencryptionkey')
                except Exception as err:
                    queues.UISignalQueue.put((
                        'updateSentItemStatusByAckdata', (
                            ackdata,
                            tr._translate(
                                "MainWindow",
                                "Problem: You are trying to send a"
                                " message to yourself or a chan but your"
                                " encryption key could not be found in"
                                " the keys.dat file. Could not encrypt"
                                " message. %1"
                            ).arg(l10n.formatTimestamp()))
                    ))
                    self.logger.error(
                        'Error within sendMsg. Could not read the keys'
                        ' from the keys.dat file for our own address. %s\n',
                        err)
                    continue
                privEncryptionKeyHex = hexlify(shared.decodeWalletImportFormat(
                    privEncryptionKeyBase58))
                pubEncryptionKeyBase256 = unhexlify(highlevelcrypto.privToPub(
                    privEncryptionKeyHex))[1:]
                requiredAverageProofOfWorkNonceTrialsPerByte = \
                    defaults.networkDefaultProofOfWorkNonceTrialsPerByte
                requiredPayloadLengthExtraBytes = \
                    defaults.networkDefaultPayloadLengthExtraBytes
                queues.UISignalQueue.put((
                    'updateSentItemStatusByAckdata', (
                        ackdata,
                        tr._translate(
                            "MainWindow",
                            "Doing work necessary to send message."))
                ))

            # Now we can start to assemble our message.
            payload = encodeVarint(fromAddressVersionNumber)
            payload += encodeVarint(fromStreamNumber)
            # Bitfield of features and behaviors
            # that can be expected from me. (See
            # https://bitmessage.org/wiki/Protocol_specification#Pubkey_bitfield_features)
            payload += protocol.getBitfield(fromaddress)

            # We need to convert our private keys to public keys in order
            # to include them.
            try:
                privSigningKeyHex, privEncryptionKeyHex, \
                    pubSigningKey, pubEncryptionKey = self._getKeysForAddress(
                        fromaddress)
            except:
                queues.UISignalQueue.put((
                    'updateSentItemStatusByAckdata', (
                        ackdata,
                        tr._translate(
                            "MainWindow",
                            "Error! Could not find sender address"
                            " (your address) in the keys.dat file."))
                ))
                continue

            payload += pubSigningKey + pubEncryptionKey

            if fromAddressVersionNumber >= 3:
                # If the receiver of our message is in our address book,
                # subscriptions list, or whitelist then we will allow them to
                # do the network-minimum proof of work. Let us check to see if
                # the receiver is in any of those lists.
                if shared.isAddressInMyAddressBookSubscriptionsListOrWhitelist(
                        toaddress):
                    payload += encodeVarint(
                        defaults.networkDefaultProofOfWorkNonceTrialsPerByte)
                    payload += encodeVarint(
                        defaults.networkDefaultPayloadLengthExtraBytes)
                else:
                    payload += encodeVarint(BMConfigParser().getint(
                        fromaddress, 'noncetrialsperbyte'))
                    payload += encodeVarint(BMConfigParser().getint(
                        fromaddress, 'payloadlengthextrabytes'))

            # This hash will be checked by the receiver of the message
            # to verify that toRipe belongs to them. This prevents
            # a Surreptitious Forwarding Attack.
            payload += toRipe
            payload += encodeVarint(encoding)  # message encoding type
            encodedMessage = helper_msgcoding.MsgEncode(
                {"subject": subject, "body": message}, encoding
            )
            payload += encodeVarint(encodedMessage.length)
            payload += encodedMessage.data
            if BMConfigParser().has_section(toaddress):
                self.logger.info(
                    'Not bothering to include ackdata because we are'
                    ' sending to ourselves or a chan.'
                )
                fullAckPayload = ''
            elif not protocol.checkBitfield(
                    behaviorBitfield, protocol.BITFIELD_DOESACK):
                self.logger.info(
                    'Not bothering to include ackdata because'
                    ' the receiver said that they won\'t relay it anyway.'
                )
                fullAckPayload = ''
            else:
                # The fullAckPayload is a normal msg protocol message
                # with the proof of work already completed that the
                # receiver of this message can easily send out.
                fullAckPayload = self.generateFullAckMessage(
                    ackdata, toStreamNumber, TTL)
            payload += encodeVarint(len(fullAckPayload))
            payload += fullAckPayload
            dataToSign = pack('>Q', embeddedTime) + '\x00\x00\x00\x02' + \
                encodeVarint(1) + encodeVarint(toStreamNumber) + payload
            signature = highlevelcrypto.sign(dataToSign, privSigningKeyHex)
            payload += encodeVarint(len(signature))
            payload += signature

            # We have assembled the data that will be encrypted.
            try:
                encrypted = highlevelcrypto.encrypt(
                    payload, "04" + hexlify(pubEncryptionKeyBase256)
                )
            except:
                sqlExecute(
                    '''UPDATE sent SET status='badkey' WHERE ackdata=? AND folder='sent' ''',
                    ackdata
                )
                queues.UISignalQueue.put((
                    'updateSentItemStatusByAckdata', (
                        ackdata,
                        tr._translate(
                            "MainWindow",
                            "Problem: The recipient\'s encryption key is"
                            " no good. Could not encrypt message. %1"
                        ).arg(l10n.formatTimestamp()))
                ))
                continue

            encryptedPayload = pack('>Q', embeddedTime)
            encryptedPayload += '\x00\x00\x00\x02'  # object type: msg
            encryptedPayload += encodeVarint(1)  # msg version
            encryptedPayload += encodeVarint(toStreamNumber) + encrypted
            target = 2 ** 64 / (
                requiredAverageProofOfWorkNonceTrialsPerByte * (
                    len(encryptedPayload) + 8 +
                    requiredPayloadLengthExtraBytes + ((
                        TTL * (
                            len(encryptedPayload) + 8 +
                            requiredPayloadLengthExtraBytes
                        )) / (2 ** 16))
                ))
            self.logger.info(
                '(For msg message) Doing proof of work. Total required'
                ' difficulty: %f. Required small message difficulty: %f.',
                float(requiredAverageProofOfWorkNonceTrialsPerByte) /
                defaults.networkDefaultProofOfWorkNonceTrialsPerByte,
                float(requiredPayloadLengthExtraBytes) /
                defaults.networkDefaultPayloadLengthExtraBytes
            )

            powStartTime = time.time()
            initialHash = hashlib.sha512(encryptedPayload).digest()
            trialValue, nonce = proofofwork.run(target, initialHash)
            self.logger.info(
                '(For msg message) Found proof of work %s Nonce: %s',
                trialValue, nonce
            )
            try:
                self.logger.info(
                    'PoW took %.1f seconds, speed %s.',
                    time.time() - powStartTime,
                    sizeof_fmt(nonce / (time.time() - powStartTime))
                )
            except:
                pass

            encryptedPayload = pack('>Q', nonce) + encryptedPayload

            # Sanity check. The encryptedPayload size should never be
            # larger than 256 KiB. There should be checks elsewhere
            # in the code to not let the user try to send a message
            # this large until we implement message continuation.
            if len(encryptedPayload) > 2 ** 18:  # 256 KiB
                self.logger.critical(
                    'This msg object is too large to send. This should'
                    ' never happen. Object size: %i',
                    len(encryptedPayload)
                )
                continue

            inventoryHash = calculateInventoryHash(encryptedPayload)
            objectType = 2
            Inventory()[inventoryHash] = (
                objectType, toStreamNumber, encryptedPayload, embeddedTime, '')
            if BMConfigParser().has_section(toaddress) or \
               not protocol.checkBitfield(behaviorBitfield, protocol.BITFIELD_DOESACK):
                queues.UISignalQueue.put((
                    'updateSentItemStatusByAckdata', (
                        ackdata,
                        tr._translate(
                            "MainWindow",
                            "Message sent. Sent at %1"
                        ).arg(l10n.formatTimestamp()))))
            else:
                # not sending to a chan or one of my addresses
                queues.UISignalQueue.put((
                    'updateSentItemStatusByAckdata', (
                        ackdata,
                        tr._translate(
                            "MainWindow",
                            "Message sent. Waiting for acknowledgement."
                            " Sent on %1"
                        ).arg(l10n.formatTimestamp()))
                ))
            self.logger.info(
                'Broadcasting inv for my msg(within sendmsg function): %s',
                hexlify(inventoryHash)
            )
            queues.invQueue.put((toStreamNumber, inventoryHash))

            # Update the sent message in the sent table with the
            # necessary information.
            if BMConfigParser().has_section(toaddress) or \
               not protocol.checkBitfield(behaviorBitfield, protocol.BITFIELD_DOESACK):
                newStatus = 'msgsentnoackexpected'
            else:
                newStatus = 'msgsent'
            # wait 10% past expiration
            sleepTill = int(time.time() + TTL * 1.1)
            sqlExecute(
                '''UPDATE sent SET msgid=?, status=?, retrynumber=?, '''
                ''' sleeptill=?, lastactiontime=? WHERE ackdata=? AND folder='sent' ''',
                inventoryHash, newStatus, retryNumber + 1,
                sleepTill, int(time.time()), ackdata
            )

            # If we are sending to ourselves or a chan, let's put
            # the message in our own inbox.
            if BMConfigParser().has_section(toaddress):
                # Used to detect and ignore duplicate messages in our inbox
                sigHash = hashlib.sha512(hashlib.sha512(
                    signature).digest()).digest()[32:]

                helper_db.put_inbox(
                    toaddress, fromaddress, subject, message, inventoryHash, sigHash,
                    encoding=encoding
                )

    def requestPubKey(self, toAddress):
        """Send a getpubkey object"""
        toStatus, addressVersionNumber, streamNumber, ripe = decodeAddress(
            toAddress)
        if toStatus != 'success':
            self.logger.error(
                'Very abnormal error occurred in requestPubKey.'
                ' toAddress is: %r. Please report this error to Atheros.',
                toAddress
            )
            return

        queryReturn = sqlQuery(
            '''SELECT retrynumber FROM sent WHERE toaddress=? '''
            ''' AND (status='doingpubkeypow' OR status='awaitingpubkey') '''
            ''' AND folder='sent' LIMIT 1''',
            toAddress
        )
        if not queryReturn:
            self.logger.critical(
                'BUG: Why are we requesting the pubkey for %s'
                ' if there are no messages in the sent folder'
                ' to that address?', toAddress
            )
            return
        retryNumber = queryReturn[0][0]

        if addressVersionNumber <= 3:
            state.neededPubkeys[toAddress] = 0
        elif addressVersionNumber >= 4:
            # If the user just clicked 'send' then the tag
            # (and other information) will already be in the
            # neededPubkeys dictionary. But if we are recovering
            # from a restart of the client then we have to put it in now.

            # Note that this is the first half of the sha512 hash.
            privEncryptionKey = hashlib.sha512(hashlib.sha512(
                encodeVarint(addressVersionNumber) +
                encodeVarint(streamNumber) + ripe
            ).digest()).digest()[:32]
            # Note that this is the second half of the sha512 hash.
            tag = hashlib.sha512(hashlib.sha512(
                encodeVarint(addressVersionNumber) +
                encodeVarint(streamNumber) + ripe
            ).digest()).digest()[32:]
            if tag not in state.neededPubkeys:
                # We'll need this for when we receive a pubkey reply:
                # it will be encrypted and we'll need to decrypt it.
                state.neededPubkeys[tag] = (
                    toAddress,
                    highlevelcrypto.makeCryptor(hexlify(privEncryptionKey))
                )

        # 2.5 days. This was chosen fairly arbitrarily.
        TTL = 2.5 * 24 * 60 * 60
        TTL *= 2 ** retryNumber
        if TTL > 28 * 24 * 60 * 60:
            TTL = 28 * 24 * 60 * 60
        # add some randomness to the TTL
        TTL = TTL + helper_random.randomrandrange(-300, 300)
        embeddedTime = int(time.time() + TTL)
        payload = pack('>Q', embeddedTime)
        payload += '\x00\x00\x00\x00'  # object type: getpubkey
        payload += encodeVarint(addressVersionNumber)
        payload += encodeVarint(streamNumber)
        if addressVersionNumber <= 3:
            payload += ripe
            self.logger.info(
                'making request for pubkey with ripe: %s', hexlify(ripe))
        else:
            payload += tag
            self.logger.info(
                'making request for v4 pubkey with tag: %s', hexlify(tag))

        statusbar = 'Doing the computations necessary to request' +\
            ' the recipient\'s public key.'
        queues.UISignalQueue.put(('updateStatusBar', statusbar))
        queues.UISignalQueue.put((
            'updateSentItemStatusByToAddress', (
                toAddress,
                tr._translate(
                    "MainWindow",
                    "Doing work necessary to request encryption key."))
        ))

        payload = self._doPOWDefaults(payload, TTL)

        inventoryHash = calculateInventoryHash(payload)
        objectType = 1
        Inventory()[inventoryHash] = (
            objectType, streamNumber, payload, embeddedTime, '')
        self.logger.info('sending inv (for the getpubkey message)')
        queues.invQueue.put((streamNumber, inventoryHash))

        # wait 10% past expiration
        sleeptill = int(time.time() + TTL * 1.1)
        sqlExecute(
            '''UPDATE sent SET lastactiontime=?, '''
            ''' status='awaitingpubkey', retrynumber=?, sleeptill=? '''
            ''' WHERE toaddress=? AND (status='doingpubkeypow' OR '''
            ''' status='awaitingpubkey') AND folder='sent' ''',
            int(time.time()), retryNumber + 1, sleeptill, toAddress)

        queues.UISignalQueue.put((
            'updateStatusBar',
            tr._translate(
                "MainWindow",
                "Broadcasting the public key request. This program will"
                " auto-retry if they are offline.")
        ))
        queues.UISignalQueue.put((
            'updateSentItemStatusByToAddress', (
                toAddress,
                tr._translate(
                    "MainWindow",
                    "Sending public key request. Waiting for reply."
                    " Requested at %1"
                ).arg(l10n.formatTimestamp()))
        ))

    def generateFullAckMessage(self, ackdata, _, TTL):
        """
        It might be perfectly fine to just use the same TTL for the ackdata that we use for the message. But I would
        rather it be more difficult for attackers to associate ackData with the associated msg object. However, users
        would want the TTL of the acknowledgement to be about the same as they set for the message itself. So let's set
        the TTL of the acknowledgement to be in one of three 'buckets': 1 hour, 7 days, or 28 days, whichever is
        relatively close to what the user specified.
        """
        if TTL < 24 * 60 * 60:  # 1 day
            TTL = 24 * 60 * 60  # 1 day
        elif TTL < 7 * 24 * 60 * 60:  # 1 week
            TTL = 7 * 24 * 60 * 60  # 1 week
        else:
            TTL = 28 * 24 * 60 * 60  # 4 weeks
        # Add some randomness to the TTL
        TTL = int(TTL + helper_random.randomrandrange(-300, 300))
        embeddedTime = int(time.time() + TTL)

        # type/version/stream already included
        payload = pack('>Q', (embeddedTime)) + ackdata

        payload = self._doPOWDefaults(
            payload, TTL, log_prefix='(For ack message)', log_time=True)

        return protocol.CreatePacket('object', payload)