Moving from PGP to GnuPG and other questions ...

Steve Butler sbutler at
Wed Apr 28 17:00:27 CEST 2004

At one time a client was sending us files encrypted with IDEA (they were a
PGP shop).  Found that there were no prefs on the key that had been
generated by GnuPG.  So, I edited the key, set the preferences and had the
client update their keyring.  They no longer send us files encrypted using

So, yes, a PGP client will honor the preferences set by GnuPG.

--Steve Butler
Oracle Administrator
First Choice Health Network
Seattle, WA USA
sbutler at

-----Original Message-----
From: Holger Sesterhenn
[mailto:Holger.Sesterhenn at]
Sent: Wednesday, April 28, 2004 6:26 AM
To: Gnupg-Users
Subject: Re: Moving from PGP to GnuPG and other questions ... 


Neil Williams wrote:

> PGP might want to prefer IDEA but what happens when you use PGP to try and

> encrypt to the GnuPG key? Preferred might mean preferred as a general rule

> rather than as a specific preference for this key.

If I import a new key to PGP which has been generated by GnuPG with its
default preferences

     Cipher: AES256, AES192, AES, CAST5, 3DES
     Digest: SHA1, RIPEMD160
     Compression: ZLIB, ZIP, Uncompressed
     Features: MDC
,done with GnuPG 1.2.3)

PGP will encrypt with CAST5 or 3DES (maybe AES).


BUT I have changed the prefs of a V4 key which has been generated with
PGP (with IDEA as default!), exported to GnuPG, *deleted* entirely from
PGP, exported from GnuPG with new prefs set and again imported from PGP.

Will say: there was a time where PGP did not know about the existence of
this key. But somewhere in PGP's key database information can be found
that this key has had IDEA as the default algo.

> Doesn't it depend on what the recipient key can use? PGP must be smart
> not to encrypt to a key using an algorithm that it knows the key does not 
> handle.

That exactly is the question!

Best Regards,

Holger Sesterhenn

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