uinmyn 0.02

8 Jul 2010

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Change log

   Add a script to enter gotten pages into a local browser-accessible
   cache.

   Improvements to the documentation.

The url@is-not-my.name Internet page fetcher [1] allows an individual
to read Internet content with strong anonymity.  Content is returned
encrypted in Usenet newsgroup alt.anonymous.messages.  No one, not
even the is-not-my.name administrator, is able to link content being
fetched with any particular individual, or with other requests.

Here are some scripts to facilitate use of url@is-not-my.name.

There are two main scripts:

   uinmyn-fetch-body.py
      -- code URLs into a request and save the key

   uinmyn-do-aam-article.py
      -- extract pages from returned a.a.m. articles

Given a (short) list of URLs, uinmyn-fetch-body.py generates a random
key for the encryption and hsub of the reply, saves the key in a local
database, and constructs the body of the request, encrypted and ready
to send through a remailer chain.

Each message from a.a.m. is then fed to uinmyn-do-aam-article.py.  If
the message matches a key in the database, the key is removed from the
database, the decrypted message is saved for further processing, and
the script returns with a positive code.  Otherwise, the script gives
a negative code.  The script is therefore useful for procmail, which
might be checking the same message for other hits.  The following
.procmailrc clause sequence will send the decrypted "inner posting" to
local-recipient.

   :0fW
   | uinmyn-do-aam-article.py /path/to/uinmyn_pending_requests_db

   :0a
   ! local-recipient

The net effect, if all goes well, is that the pages addressed by URLs
submitted to uinmyn-fetch-body.py show up, after privacy-protecting
remailer random latencies.  No record leaves your site of who accessed
the pages.

Also provided here is are minor support scripts to list the URLs in a
given reply, and to insert page content into the browser-accessible
cache provided by wwwoffle [2].

Out of respect for your privacy, uinmyn does not require you to access
any web site for its installation or use (though you may if you wish:
mailto:stealthsuite@nym.mixmin.net).  Everything is right here in this
posting.

ABOUT THE CODE

Succinctness and readability are given priority here over efficiency.
If efficiency becomes an issue, there are lots of opportunities here
for speedup.

These scripts are meant mainly as hints for you to adapt to the needs
of your particular case.  But they could be used verbatim if you like
the way they are structured.

INSTALLATION

   Have python, gnupg, and mixmaster installed.
   Have the send@is-not-my.name public key on your gnupg keyring.
   Copy the scripts from below to somewhere on your executables path.

Of course, you are taking a full feed of a.a.m at all times without
interruption, separating wheat from chaff only after it's all behind
closed doors.  Otherwise, the world is informed about which articles
you find interesting.

Remember, long random latency is part of the price of untraceability.
It can't be done with TOR or any other low-latency method.

EXAMPLE

Typing

   uinmyn-fetch-body.py db | mixmaster url@is-not-my.name
   http://www.bananasplit.info
   ^D

will send a request for http://www.bananasplit.info.  The key is added
to db, which need not have existed beforehand.  (It's plain ASCII, so
you can look at it to better understand what's happening.)

Later, in a directory full of fresh a.a.m articles, the command

   for f in *; do uinmyn-do-aam-article.py db < $f >> mbox; done

will append the requested content to mbox if it has arrived.

FOOTNOTES

[1] http://www.is-not-my.name
[2] World Wide Web OFFline Explorer http://www.gedanken.demon.co.uk/wwwoffle/

TODO

   Use PIPE for the gpg stdin in uinmyn-do-aam-article.py.

BUGS

   Encryption/hsub keys are exposed briefly during a.a.m. processing.

Here are the scripts.

8<--------8<--------8<--------8<--------8<--------8<--------8<--------
#! /usr/bin/python

# SYNOPSIS
#   uinmyn-fetch-body.py <pending-requests-dict>

# DESCRIPTION

#   Reads URLs from standard input, one per line, generates a fresh
#   random key to encrypt the reply and for its hsub, adds the key and
#   the requested URLs to pending-requests-dict (creating it anew if
#   it doesn't exist), constructs and encrypts a request for
#   url@is-not-my.name, and writes it to standard output.

from os import urandom
from base64 import standard_b64encode
import sys, os
import pprint
from subprocess import Popen, PIPE

UINMYN_PENDING_REQUESTS = sys.argv[1]

# same key for both encryption and hsub:
key  = standard_b64encode(urandom(15))

gpgproc = Popen('gpg -e -a -r send@is-not-my.name --trust-model always --no-emit-version --batch', shell=True, stdin=PIPE)
gpgproc.stdin.write("KEY " + key + '\n')

urls = []
for line in sys.stdin.readlines():
    urls.append(line.rstrip())
    gpgproc.stdin.write('SOURCE ' + line.rstrip() + '\n')

gpgproc.stdin.close()

# Not dealt with here: Mutually exclusive access to the
# UINMYN_PENDING_REQUESTS database, as would be required if request
# issuance might be concurrent with a.a.m. processing.

if os.path.isfile(UINMYN_PENDING_REQUESTS):
    execfile(UINMYN_PENDING_REQUESTS)
else:
    uinmyn_pending_requests = {}
uinmyn_pending_requests[key] = urls

new_upr_fd = open(UINMYN_PENDING_REQUESTS, 'w')
new_upr_fd.write('uinmyn_pending_requests =\\\n')
pprint.pprint(uinmyn_pending_requests,stream=new_upr_fd)
8<--------8<--------8<--------8<--------8<--------8<--------8<--------
#! /usr/bin/python

# SYNOPSIS
#   uinmyn-do-aam-article.py <pending-requests-dict>

# DESCRIPTION

#   Reads an article from standard input.  If its Subject: might be an
#   hsub, check it against each key in pending-requests-dict in turn.
#   If a hit is found, decrypt the inner posting and write it to
#   standard output.

import sys, os
from hashlib import sha256
import email
import pprint
from subprocess import Popen

UINMYN_PENDING_REQUESTS = sys.argv[1]

posting = email.message_from_file(sys.stdin)
subject = posting.get('Subject')

try:
    iv = subject[:16].decode('hex')
except TypeError:
    sys.exit(1)

# Not dealt with here: Mutually exclusive access to the
# UINMYN_PENDING_REQUESTS database, as would be required if request
# issuance might be concurrent with a.a.m. processing.

if os.path.isfile(UINMYN_PENDING_REQUESTS):
    execfile(UINMYN_PENDING_REQUESTS)
else:
    uinmyn_pending_requests = {}

for key, urls in uinmyn_pending_requests.iteritems():
    if subject == (iv+sha256(iv+key).digest()).encode('hex')[:48]:
        # Doing part of the job in shell:
        gpgproc = Popen('mkfifo $HOME/passwdf ; (echo ' + key + ' > $HOME/passwdf &); echo "' + posting.get_payload() + '" | gpg --passphrase-fd 3 3<$HOME/passwdf --trust-model always --batch 2>/dev/null ; rm $HOME/passwdf', shell=True)
        # Other processing that could be done here:
        #  Deal with discrepancies between requested and obtained URL lists.
        #  Save the used key in an archive, rather than losing it forever.
        del uinmyn_pending_requests[key]
        new_upr_fd = open(UINMYN_PENDING_REQUESTS, 'w')
        new_upr_fd.write('uinmyn_pending_requests =\\\n')
        pprint.pprint(uinmyn_pending_requests,stream=new_upr_fd)
        sys.exit(0)
sys.exit(1)
8<--------8<--------8<--------8<--------8<--------8<--------8<--------
#! /usr/bin/python

# SYNOPSIS
#   uinmyn-list-gotten-urls.py

# DESCRIPTION

#   List the URLs in the url@is-not-my.name "inner mail" on standard
#   input together with the sizes of the fetched pages.

import sys, email

pages = email.message_from_file(sys.stdin)
for page in pages.get_payload():
    print(page.get('Content-Description') + ', size = ' + repr(len(page.get_payload())))
8<--------8<--------8<--------8<--------8<--------8<--------8<--------
#! /usr/bin/python

# SYNOPSIS
#   uinmyn-to-wwwoffle-cache.py

# DESCRIPTION

#   Given a (decrypted) url@is-not-my.name "inner posting", enter each
#   page that it contains into the wwwoffle cache, overlaying any
#   previous content having matching URLs.

import sys, os, email
from subprocess import Popen, PIPE

pages = email.message_from_file(sys.stdin)
for page in pages.get_payload():
    p = Popen('wwwoffle-write ' + page.get('Content-Description'), stdin=PIPE, shell=True)
    p.stdin.write('HTTP/1.0 200 OK\n')
    p.stdin.write('Content-Type: ' + page.get('Content-Type') + '\n\n')
    p.stdin.write(page.get_payload())
    p.stdin.close()
    p.wait()
8<--------8<--------8<--------8<--------8<--------8<--------8<--------

 -- StealthMonger
	 <StealthMonger@nym.mixmin.net>

 --
   stealthmail: Scripts to hide whether you're doing email, or when,
   or with whom.
         mailto:stealthsuite@nym.mixmin.net

Finger for key.

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