security projects thoughts

[Jeff Johnson]

On Apr 18, 2011, at 12:45 PM, Daniel J. Luke wrote:

> On Apr 18, 2011, at 12:36 PM, Jeff Johnson wrote:
>> 
>> And a generated keypair with the private key discarded and
>> the public key registered with time stamp differs ... how?
> 
> Where is the public key registered? Does the end-user installer do something like:
> 

In the scheme I outline, the package itself "registers" the pubkey.

If you don'y like "self signing", devise something different. There's
all sorts of ways to register pubkeys. If I'm forced to continue
with a registrar for RPM, then I will use a private SKS keyserver
submission and include a RFC 3161 trusted time stamp, most likely
from the service at startssl.

> 1. Check that the public key in the package matches the registration (presumably in a way that isn't easy to spoof)
> 2. Validate the package contents via the signature and the registered public key
> 

Yes. One would go through all the usual rituals to ensure that
the pubkey in the package agrees with whatever is registered.

The signature plaintext *IS* based on the package itself. But
yes the whole scheme of signing is driven by actually verifying
the signature. If all you have is the signature, well, all you have
is a cup of bit soup.

> ? 
> 
> I think I missed the description of the public key registration, but it seems like that's an important part (which makes it more than 'just a larger hash').
> 

Since RPM (unlike every other software installer in the world) lacks
MANDATORY ssignature checking, the non-repudiable signature GUARANTEES
to the bikeshed that a signature always exists.

Now if I wait another 6+ years, the loony linux bikeshed discusssions
may permit me to rearrange perhaps 20 lines of code to make signature
checking MADATORY on all packages installed.

But I'm not gonna hold my breath, been at this for 6+ years already,
and I likely will have qubits installed everywhere on iPad's before
the full implementation is finished.

Hint: Yes you need to write your installer from day 0 to _ALWAYS_
verify singnatures lest the bikeshed express their preference for
chewing bubble gume scraped off the bottom of the chair:

	Have it your own way!

73 de Jeff
-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 4645 bytes
Desc: not available
URL: <http://lists.macosforge.org/pipermail/macports-dev/attachments/20110418/d7ba8c52/attachment-0001.bin>