[Cialug] dumb gpg question

[D. Joe Anderson]

On Fri, Jul 22, 2005 at 03:49:24PM -0500, Don Cady wrote:
> Q1. 'They' being us people (do it manually), or the application(s)?
> Q2. So you end up sending an extra file, or does it all get combined into 
> one?

Ken has given the theoretical/analytical answer to this, which I
appreciate his doing.

Here's a touch of empiricism to complement that:

$ mkdir gpgtest

$ cd gpgtest

$ dd if=/dev/urandom of=test.clear bs=512 count=4
4+0 records in
4+0 records out

$ gpg -r dlg at iastate.edu -e test.clear

$ gpg -r dlg at iastate.edu -r deejoe at iastate.edu -o test.clear.both.gpg -e test.clear

$ ls -al
total 20
drwxr-xr-x    2 deejoe   deejoe       4096 Jul 22 20:21 .
drwxr-xr-x    3 deejoe   deejoe       4096 Jul 22 20:21 ..
-rw-r--r--    1 deejoe   deejoe       2048 Jul 22 20:21 test.clear
-rw-r--r--    1 deejoe   deejoe       3432 Jul 22 20:21 test.clear.both.gpg
-rw-r--r--    1 deejoe   deejoe       3128 Jul 22 20:21 test.clear.gpg

So, no, you don't get two copies of the original, otherwise
test.clear.both.gpg, which is encrypted for two recipients,
would be >6256 bytes, or, more than twice as large as
test.clear.gpg, which is encrypted for only one recipient.
 

> >There is juju-magic, remember that they generate a random key, encrypt
> >the body using it, then encrypt the key with the public key.  So it will
> >get slightly larger, but not dramatically.
> >
> >James
> 
> 
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-- 
-- 
D. Joe Anderson         http://www.etrumeus.com/~deejoe
"DRM [...] is to copyright law as a machine gun on                                          
a motion detector is to real estate law"  -- Don Marti