Subject: Re: Incompatibility between NAI command line and PGP 8.0 keys

From: <[email-masked]>
Date: Wed, 30 Jul 2003 10:06:24 -0700

On Tue, 29 Jul 2003 11:00:59 -0700 Hal Finney <[email-masked]> wrote:
>
>Hi, at NAI we have a report that some PGP 8.0 keys can't be imported
>into the NAI "E-Business Server" command line version 7.1.1.  Can
>someone post an 8.0-generated key and I will see if there are any
>problems importing it?  We want to be sure and retain compatibility
>between the various OpenPGP implementations if possible.

i posted two keys generated in pgp 8.02, here:
http://www.angelfire.com/pr/pgpf/pgp802keypairs.html

the first key, 'rsav4pgp8' was generated with a passphrase the same as
the name:  rsav4pgp8
and by default, uses aes-256 as the protect cipher

the second key, 'dhpgp8', was generated without a passphrase

both are usable in pgp pre-8 versions

the incompatibility you referred to was present in pgp 8.0,
when it was made compatible with the newer gnupg secret key format,
and keys that were exported from that version of pgp 8,
could not be used in pre-8 versions,

hth,

vedaal

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---

From: <[email-masked]>
Date: Wed, 30 Jul 2003 15:10:45 -0700

On Tue, 29 Jul 2003 21:53:47 -0700 Will Price <[email-masked]> wrote:
>
>This sounds to me very much like a private key format issue and not
>a 
>general public key issue. We made many changes in PGP 8 to adhere
>to 
>the OpenPGP RFC more closely and improve compatibility with other
>>
>OpenPGP implementations. As part of this, changing the passphrase
>of a 
>key or generating a new key in PGP 8.0.2+ will use the newer 0xFE
>>
>private key format from the Secret Key Packet Formats section of
>the 
>draft.

this is very interesting !

i just tried it out by exporting a key generated in gnupg 1.2.2 with
the new s2k hash protection, which does not work in pre-8 pgp (except
for ckt build 9), but does work without any problems in pgp 8.0.2

now here is where it becomes sort of surprising:

[1] if the imported gnupg key which works in pgp 8.0.2, is exported from

pgp 8.0.2, it will still not work in pre-8 pgp

[2] if the passphrase is changed in pgp 8.0.2, and then exported, it
still does not work in pre-8

[3] if the passphrase is removed in 8.0.2, and exported without a passphrase,
 then it 'does' work, in pre-8

[4] if the passphrase is removed in 8.0.2, and then then changed in 8.0.2,
 and then exported,
it still acts like the original gnupg and does 'not' work in pre-8
(even though the passphrase is changed in 8.0.2 after the passphrase
has been removed, the new pgp 8.0.2 one is still not a simple s2k hash)

*but*

[5] if the key is imported from 8.0.2 into pre-8 with the passphrase
removed in 8.0.2,
and the passphrase then changed in pre-8, 
then it does work

(probably since pre-8 does not have the capacity to produce the complex
s2k hash, so it does not, whereas pgp 8.0.2 does have this capacity,
so it produces it by default for this type of key, but not for other
keys generated de-novo in pgp 8.0.2)

these different key import/export variations can become very hard to
keep track of ;-)

would suggest/request:

(a) pgp 8.0.x have something in the key properties that identifies
the s2k hash type (simple or complex-gnupg-type)

(b) pgp 8.0.x allow the user to choose the s2k hash type when changing
the passphrase,
{and in the interests of maximum intercompatibility, have the default
be the simple s2k hash, which can be then be changed in gnupg to the
more complex one if desired, but will stillbe compatible in pre-8 pgp
by default}

with Respect,

vedaal