gpg: NOTE: cipher algorithm 9 not found in preferences

[Nick Andriash]

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On March 12, 2001 at 8:48:44 AM, Stefan H. Holek wrote:

> NOTE: cipher algorithm 9 not found in preferences

> This means something like:

> a) You have selected RIJNDAEL256 (sym 9) as your symmetric alg

Yes, I would prefer to encrypt messages and receive encrypted messages
using that Algorithm, but if that particular Algo is not found in the
Recipients Key preferences, then I would want GPG to use the first
Algorithm listed in their preference list. Is that possible?

> b) The key you have been encrypting to is not offering this    algorithm in its preferred
> sym alg subpacket. 
>    If you type gpg --list-packets thekeyfile.asc you might see:       ...
>       hashed subpkt 11 len 5 (pref-sym-algos: 7 10 3 4)
>       ...

>    Which means: RIJNDAEL128, Twofish, CAST5, Blowfish

> c) GnuPG has used sym alg 9 for encryption (as told) and gives the
>    mentioned notice when decrypting.

But in my case, the Recipient is me, and the Key was generated with
Rijndael-256 as my preferred Algorithm. The note in that case is telling
me that Rijndael-256 is not available. So, if it's not available, what
Algorithm was used? When I type --version, I am shown the following:

Supported algorithms: Cipher: 3DES, CAST5, BLOWFISH, RIJNDAEL,
RIJNDAEL192, RIJNDAEL256, TWOFISH

By looking at the above list, I am presuming that Rijndael-256 *is*
available, so I am a little confused why I am getting that notation when I
send an encrypted test message to myself. BTW, is that my preference list?

> d) There should be no need to specify a sym alg in normal operation
>    as it will automatically be selected form the key preferences.

So in that case, cipher-algo should be left blank, but that does not seem
to be possible when editing your GPG Options through GnuPGTray. Can I
therefore simply delete the cipher-algo line in my Options File?

Basically, through my Options File I want to say to others that I prefer
to receive messages encrypted using the Rijndael-256 Symmetric Algorithm,
but if you don't have that capability, then use Twofish, and failing that,
use 3DES, then CAST5 followed by Blowfish. Now, in my case where I am
using a precompiled binary for use in Windows, is it possible to edit my
Preference List, or do I have to accept the default? BTW, what is the
command to see the default list?

With reference to *sending* encrypted messages, my preference again would
be Rijndael-256. If however, the Recipient cannot accept that Algorithm,
does GnuPG use the first of the preferred Algorithms on the Recipients Key
Preferences... which I presume is hidden somewhere in his
self-signature... or am I *forcing* the Recipient to accept encrypted
messages using Rijndael-256?



Nick


   -=N.J. Andriash | Vancouver, B.C. Canada=-     
  [ TB! v1.52 Beta 1 | Win 98 SE 4.10 2222 A ]     
[ GnuPG v1.0.4-1 (MingW32) | Key ID: 0x7BA3FDCE ]      
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