How to convert (ancient) key in "version 2" to more modern "version 4" format?

[Bjoern Kahl]

Am 24.05.16 um 08:32 schrieb Werner Koch:
> On Mon, 23 May 2016 21:56, mls at bjoern-kahl.de said:
> 
>>  :public key packet:
>> 	version 2, algo 1, created 1022270000, expires 0
> 
> That was created by an very old PGP-2 versions.  gpg bever created a
> version 2 key.
> 
>>  Is there a way to have gpg2 convert and export the key?  Looking
> 
> The formats are diffefrent and even if you would use the same key
> material, the fingerprint and the keyid will be diffewrent.  Thus there
> is no practial way of using it [1].

> [1] if you use the key material and make a v4 key out of it, gpg should
>     be able to decrypt keys with a wild-card keyid (--throw-keyid in
>     gpg, can't remember the PGP-2 option).
> 

 thanks a lot for the explanations.

 So while theoretically possible, it would be a pretty useless
 exercise, since it would change the keyid and break all collected
 signatures.

 Which leaves me with the other option, teach mailvelop / openpgp.js
 to read v2 keys.

 Looking at the RFC-4880, it seems V3 and V2 keys share the same
 structure (section 5.5.2, page 41).  Openpgp.js does handle V3 keys,
 but not V2.  Which makes me wonder if it is enough to let V2 keys run
 through the same code path as the supported V3 keys, or if I am
 missing something important here.


 Thanks

    Björn

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