Recovery of PCSECURE files and bogus GnuPG algorithms

[Leigh S. Jones]

"Your friend" encrypted a message to Phil Zimmerman, who has
been known to use PGP from time to time.  It makes little sense
for him to encrypt messages to PRZ using PRZ's keys but also
using ciphers that PRZ cannot be expected to decrypt.  This is
not about PRZ being on his "high horse".  "Your friend" was
playing stupid pranks sending messages using twofish and tiger.
Judging by the content of PRZ's responses your friend was
badgering him for help that he was not in a position to give.  If
"your friend" wants to correspond with PRZ then he should
consider taking the lines:

cipher-algo twofish
digest-algo tiger192

out of his options file completely and replacing them with:

openpgp

or

pgp6.

Having been given the advice once, I'd also suggest your
friend heed PRZ's recommendations regarding PCSECURE,
and the unrecovered data.  If the data is valuable, hire a
consultant.

----- Original Message -----
From: "john clark" <lurq_gnupg@yahoo.com>
To: <gnupg-users@gnupg.org>
Sent: Tuesday, June 18, 2002 9:14 PM
Subject: Recovery of PCSECURE files and bogus GnuPG algorithms


>
>
> hi guys,
>
> the ff is a record of correspondence that took place
> between my friend and Mr. Zimmermann last June 10.
>
> My friend was asking PRZ some help about an old DOS
> encryption program he got problems with.
>
> He encrypted the message to PRZ using gpg, but some of
> the gnupg options were altered, like tiger loaded,
> cipher-algo twofish digest-algo tiger192, etc...
>
> PRZ was unable to decrypt the message. The ff email
> messages follow this.
>
> =======================================================
>
> From: Philip Zimmermann <prz@mit.edu>
> To: "John Edward R. Mallen" <trauma@surgical.net>
> Subject:  Re: Recovery of PCSECURE files and bogus
> GnuPG algorithms
> Date:  Mon, 10 Jun 2002 10:35:17 +0200
>
>
> Sorry, Jed, I have no experience with PCSECURE.  Never
> used it
> or even seen it.
> You might have to hire a consultant to spend the time
> looking
> into the matter.
> I could spend some time on it, but that would run you
> $2000/day.
>
> There are companies that specialize in this kind of
> data
> recovery.  One is AccessData,
> which I presume might use accessdata.com as its web
> address.  I
> can't check if that
> is the right URL now, because I'm on a plane high
> above Bangkok
> at the moment.  I'll
> upload this email when I reach Perth.
>
> Changing the subject-- I'm curious how you generated
> the earlier
> message to me,
> the one that had a bad session key due to using the
> wrong
> algorithm in GnuPG.
> Exactly what GnuPG settings did you use to generate
> that
> message?  You had to override
> my own public key's settings to generate that message
> with that
> algorithm.  How did
> you do that?
>
> I noticed this time you left off the GnuPG version
> labels, which
> are purely cosmetic.
> Were you worried that they would somehow offend me for
> not using
> the real PGP?
> Believe me, it was not a question of what product you
> were
> using.  It was a question
> of using a nonstandard algorithm within the product.
>
> Regards,
> Phil
>
>
> On Friday, June 7, 2002, at 04:12  PM, John Edward R.
> Mallen wrote:
>
> > ....
> >
> > How can I go about this task?
> >
> > Thanks.
> >
> > - jed
> >
> >
> > -----BEGIN PGP PUBLIC KEY BLOCK-----
> >
> >
> mQGiBDko8IQRBADdu9tQ6Ok1dSByiX+NB6UrK4qk1PLrMSCq+5TnJ+JnBFpLS++3
> >
> LTDTrBNajowm/ImOkdvxrvlhMrZmZ20Tm1qJyLx0PjTSb962fxnBSLocmuC08YV5
> >
> gurFzb2a7ngcd/8owPbgYtVDFhCxeNnu+Zo6FC8GmsuycSS0lHXb8W7xFwCgzLcB
> >
> 5DKPRtTe/peoB/hZardZauED/jKY/dS6In5PjtM5GegwjSHRgse1nAGUXL4HAdvz
> >
> /yCa5dg8KcBVNLTZ5jg+iIoagoRxIBD4hj7QQtgVPrB5gq5ymLjVcY06pxobl54C
> >
> btRHJLsMfZUvxIcdWChRo+C6RYkT8IpWsT++CqjcCWfYhNW1c2A31aEQfDt7H5WN
> >
> VmDtA/9oDzIfBh35SHgiOJbsxajHxuyo2RnEkku9NUXZ8D3oqU+svGhQGhksOkWw
> >
> S9w/1THdo3kshHg0bWMykkC/4R3INzk283o/JYIxG39BNxWcdrCvPbof9BYMjyh2
> >
> fkBCYDZN5/KEyr3x0vcxiXL950rLJgVWMpeV3TZ3tDPjNfVfJLQjSmVkIFIuIE1h
> >
> bGxlbiA8dHJhdW1hQHN1cmdpY2FsLm5ldD6IXAQTEQIAHAIeAQIXgAcLCQgHCgME
> >
> AxUDAgMWAQIFAjko8IYACgkQluOtB0iIhFjTIwCdGKqeySZA/Xr23EXYRn1NWrpg
> >
> 05gAn2sdc06lAZrYLwlWmgozTDuaJojruQMNBDko9vgQDADKcCHxPqyVgF/LFkqT
> >
> hMQbL+PkO7az8KCYYKFO84LsTVZ8/N37YadXJSpsy0s86aTZ/ahNzoqLWIwInOrt
> >
> OFft7fbT9wmBvAUJB7tTinNNhMA96jSgIgJFrjXqqP0w7/JJYhsirAFmKh9Yp1mn
> >
> U+Yvoolxf1ioTesEXetUGie9l1PlgQuxu41av+EmoF2igiKxlmvZZQiJkX0/GaQ4
> >
> 1CC5oqFbnDdAKD4pVZHOo1pBIMvvFudbFr2GZTEEQSZ2+mJ41ozJgAVjeiFNt1kj
> >
> v5lLROYbgE/NMqDZKyaiDjzza/gfvwIYeg4QlMxOPn8TWQdOutZ3V5DiKZ7XOLtx
> >
> 4VpUCCT5zGPbrtU7p34sQfFNF4sDxd7c+mWtn3rJDieH/x7P+7WE2HgZ31hNPHeU
> >
> HWlPs/VJ84+CswB24s3Bj6Rbvuy9J4u3aNmm8Mi+qGf35f0rfjHYOZuC+lMGBIOp
> >
> bjkywncD99c6jAlP4FqKLHoSIZRqcKKF2jrI/CVin7MYbksAAwUL/inihvRKrbhC
> >
> q616GrKRndhj8H6bde4sjcVvJ/PWFxbgdupHP4oa8IVjXxjSBA0Y4i8gGcUIZviF
> >
> FWzJ+rS5hvqbA6lnpzGCBB9Z1K8fEN60Kk1LXOaq2SaYHKfW4+BV7brlnQZJifsX
> >
> z2TBoO+WeZ4eBY/C/wfq8E1Fbgqcst/zBdAJpujTzDutBDjd9TItMP9GuY1RrNEl
> >
> cMMjj/JCgYp0i+RvGMHnBx3ft8BMDQ1Oe4rb2Cm0nIDI2nVwsWKo0N8xt4hjoclR
> >
> 6KnpTHeIBUKtX/WIrc+VbEYNfYJuzhvKrcPeQ8miobX7swufKP2zp7YQFKIDz5Tj
> >
> 1wDkDXRp1CRVtuJgpTnhrWABdC3DZ2031+QXdTgDlJMa44TRpvAYvvdFavFZ/LyC
> >
> V6XPIaun02Kw4ng8DGprn6jbGnKHZa8RFXBHbP0izEYr9TolRVaNCI6pv+PIJYUY
> >
> MXa3FCjVluLfLI5WnMjRpMM6KXDwOYtza30vv1RsShfNPOtSgI4Bc4hGBBgRAgAG
> >
> BQI5KPb4AAoJEJbjrQdIiIRYH3EAoJKy28HpALXp+7Ts5k8lg3+JEpkxAJ9C3Bno
> > cKjsKsQZ5rn2cl5ZgmeJQQ==
> > =bFd0
> > -----END PGP PUBLIC KEY BLOCK-----
> >
> >
>
> Philip R Zimmermann        prz@mit.edu
> http://philzimmermann.com  tel +1 650 322-7377
> (spelled with 2 n's)       fax +1 650 322-7877
>
>
>
> =================================
>
> my consequent lame reply...
>
>
> >> Sorry, Jed, I have no experience with PCSECURE.
> Never used it
> >> or even seen it....
> >
> > Thank you sir, but I've decided to just learn 8086
> asm or
> > anything that'll help me open this encrypted file. I
> don't
> > really know how I'm supposed to go through with this
> but even
> > if I can't be successful in this endeavor, there's
> no loss in
> > learning something, right? Wish me luck :)
> >
> >> Changing the subject-- I'm curious how you
> generated the earlier
> >> message to me,
> >> the one that had a bad session key due to using the
> wrong
> >> algorithm in GnuPG.
> >> Exactly what GnuPG settings did you use to generate
> that
> >> message?  You had to override
> >> my own public key's settings to generate that
> message with that
> >> algorithm.  How did
> >> you do that?
> >
> > I'm currently using GnuPG 1.0.7.
> > My ~/.gnupg/options file at the time I encrypted
> that message
> > has the ff settings:
> >
> > #--------------------
> > default-key jed
> > load-extension tiger
> > cipher-algo twofish
> > digest-algo tiger192
> > #--------------------
> >
> > Maybe it overrode your public-key algo preferences,
> although
> > I'm not sure if it can do that. Probably not. For
> sure I cannot
> > change your preferred algorithms because I don't
> have your
> > secret key.
> >
> > Must be that I encrypted the message to your pubkey
> but it also
> > encrypted it to my key because of the default-key
> preferences.
> > But in this case you can still decypt the message,
> right? I
> > tried decrypting the cipher text but I can't. stderr
> says I
> > don't have your secret keys.
> >
> > BTW, my preferences for the key I used was I think,
> S10 S9 S8
> > S7 S3 S4 S2 H2 H3 Z1 Z2
> > though I'm not really sure because I already changed
> it to have
> > Rijndael256, Rijndael192, and Rijndael after reading
> on the AES
> > contest some.
> >
> >
> >> I noticed this time you left off the GnuPG version
> labels, which
> >> are purely cosmetic.
> >> Were you worried that they would somehow offend me
> for not using
> >> the real PGP?
> >
> > A bit, yes. I emailed you sometime in 1998 about how
> great PGP
> > was after using it for the first time. I asked you
> to send me
> > an encrypted email. You said you were busy but you
> still
> > replied which was a big thing for me. Someone who I
> hold in
> > high regard (like a rockstar of some sort) sends me
> email. I
> > was so naive at that time. I don't know if you still
> remember
> > that. Probably not.
> >
> > I still use PGP 6.5.8 on my other linux box. I just
> like to
> > play with GnuPG because it gives me more room to
> fool around
> > with crypto.
> >
> >> Believe me, it was not a question of what product
> you were
> >> using.  It was a question
> >> of using a nonstandard algorithm within the
> product.
> >
> > I'm confused by this. By standard do you mean
> OpenPGP or just PGP?
> >
> > Can I ask you some more questions?
> >
> > Do you keep in touch with the GnuPG people?
> >
> > If Twofish or some other cipher algorithm is not
> used in PGP,
> > does it mean that you think this algorithm is weak?
> >
> > Or just that it is not designed as well as AES but
> is still
> > secure in itself?
> >
> > THANK YOU SO MUCH Mr. Zimmermann. You don't know how
> much it
> > means to me to correspond with you. Thank you for
> not having a
> > large ego and being so down to earth.
> >
> > - Jed
> >
> >
> >
> > --
>
>
>
======================================================================
=
> and his answer....
>
> From: Philip Zimmermann <prz@mit.edu>
> To: "John Edward R. Mallen" <trauma@surgical.net>
> Cc:
> Subject:  Re: Recovery of PCSECURE files and bogus
> GnuPG algorithms
> Date:  Tue, 18 Jun 2002 23:14:44 +0800
>
>
> I am paying $10/minute to type this reply from Tokyo,
> so I don't
> have time to tutor you from my hotel room.
>
> Just follow my advice without exp[lanation:  Eliminate
> all
> algorithms from your preferences that are not
> supported by the
> real PGP.
>
> Eliminate any hashes except SHA1, no other hashes.
> Also
> eliminate Elgamal signatures (but leave el gamal
> encrytion).
> Eliminate Blowfish.  Eliminate TIGER stuff.
>
> I can't spend another $30 to explain why.  Just do it,
> if you
> value expert advice.
>
> ------------------------------------------------------
> Philip R Zimmermann        prz@mit.edu
> http://philzimmermann.com  tel +1 650 322-7377
> (spelled with 2 n's)       fax +1 650 322-7877
>
>
> =========================
>
> Would it be advisable for my friend to follow PRZ's
> advice and just use the PGP algorithms? What if my
> friend wants twofish more? Then people like PRZ won't
> be able to read his email right?
>
> What do you guys think? I think PRZ should get down
> from his high horse and stop sour-graping about GnuPG.
>
>
>
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