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From: Chris Rebert on 5 May 2010 21:44
On Wed, May 5, 2010 at 6:12 PM, Vincent Davis <vincent(a)vincentdavis.net> wrote:
> I can't think of a way to do this, not sure it is possible but I feel as though I might not know what I don't know.
> I want to share and example of a python script, to run it needs a google username and password. Is there a way for me to encrypt my username and password in the source code? I though about openID but don't really know anything about it.

Nope. What you're asking for is essentially a form of DRM by including
the information in a way the program can use it but the user can't
extract it; DRM schemes have been broken many times and the idea is
flawed even in theory, for if a person has control of their computer
(or in the limit case, at least physical access to its innards), they
can just watch the computation (e.g. memory snoop) until the data gets
converted to its plain form so the program can actually utilize it,
and then bada-bing, they have your valuable data.

Think of it this way. If you encrypted the information in your
program, the program would need to be able to decrypt it later so it
could actually use the login info. For it to be able to do that, you'd
have to include the encryption key in plaintext somewhere in the
program so it could pass it into the decryption algorithm. But then
someone can put 2 and 2 together, see that "there's his key!", and
decrypt your info using the key. So, to prevent this, the key *itself*
would then have to be encrypted...by another key, which again would be
stored in plaintext in your program somewhere, where someone could
then find it and use it to decrypt the first key and then your data,
so you use yet another key to encrypt that key...(as you can see, this
goes on ad infinitum, and thus the whole scheme is doomed). See also
section 1, "DRM Systems Don't Work", of
http://changethis.com/manifesto/show/4.DRM

You can alternatively just try to obfuscate it, but that's obviously
not truly secure and is likewise easily circumvented.

Just let the user input their own Google Account info. If you're
trying to show an example that depends on your own exact account, just
include a transcript of your terminal session (omitting your Google
Account info obviously).

Cheers,
Chris
--
DRM is http://defectiveByDesign.org
http://blog.rebertia.com
From: Tim Chase on 5 May 2010 21:48
On 05/05/2010 08:12 PM, Vincent Davis wrote:
> I can't think of a way to do this, not sure it is possible but I feel as
> though I might not know what I don't know.
>
> I want to share and example of a python script, to run it needs a google
> username and password. Is there a way for me to encrypt my username and
> password in the source code?

No-ish. You can encrypt it, but if you encrypt it, you need to
include the keys or algorithm for decrypting it, and all it takes
is a pdb.set_trace() before the decrypted uname/pwd get sent to
Google to get it, and poof all your encryption/decryption has
been in vain:

uname = SUPER_ENCRYPTED_USER
pwd = SUPER_ENCRYPTED_PASSWORD
u = secret_decrypt(uname)
p = secret_decrypt(pwd)
# regardless of how good the stuff above is
# you're vulnerable right here:
# print "%r %r" % (u, p)
do_google_stuff(u, p)

Unless the Google API you're using allows for chain-of-authority
creation of sub-credentials (so your account creates secondary
accounts that are then distributed in your code/config files and
managed via your dev login), two possibilities that come to mind:

1) put in a bogus uname/password and make them get their own
Google login to put in (which can be done in a config file if
they're squeamish about editing source code) This assumes that
any arbitrary Google login can grant access to what you want
(sometimes this is a developer key, in which case the user would
need to get their own dev key).

2) create a web-service on a server somewhere that has your
credentials, but your distributed code merely hits this web
service instead of having your actual credentials in the source
(plain-text or encrypted). The server would have them (I'd just
put them in plain-text -- no need to be fancy. If you can't
trust your hosting service, don't use them) but you wouldn't
expose the credentials outside the application.

-tkc




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