GNU bug report logs - #47634
Accompany .asc and .DIGESTS keys for the ISO

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: bo0od <bo0od <at> riseup.net>
To: bug-guix <at> gnu.org
Subject: Accompany .asc and .DIGESTS keys for the ISO
Date: Wed, 7 Apr 2021 05:42:40 +0000

Hi There,

I see there is only .sig provided:

https://guix.gnu.org/en/download/

Its better to provide more than one way of verification e.g:

Qubes: https://www.qubes-os.org/downloads/
Whonix: https://www.whonix.org/wiki/VirtualBox/XFCE
...etc

ThX!

Message #8 received at 47634 <at> debbugs.gnu.org (full text, mbox):

From: Leo Famulari <leo <at> famulari.name>
To: bo0od <bo0od <at> riseup.net>
Cc: 47634 <at> debbugs.gnu.org
Subject: Re: bug#47634: Accompany .asc and .DIGESTS keys for the ISO
Date: Thu, 8 Apr 2021 13:03:36 -0400

On Wed, Apr 07, 2021 at 05:42:40AM +0000, bo0od wrote:
> Hi There,
> 
> I see there is only .sig provided:
> 
> https://guix.gnu.org/en/download/
> 
> Its better to provide more than one way of verification e.g:

Why?

Message #11 received at 47634 <at> debbugs.gnu.org (full text, mbox):

From: bo0od <bo0od <at> riseup.net>
To: Leo Famulari <leo <at> famulari.name>
Cc: 47634 <at> debbugs.gnu.org
Subject: Re: bug#47634: Accompany .asc and .DIGESTS keys for the ISO
Date: Thu, 8 Apr 2021 17:34:20 +0000

This is nicely written by Qubes documentation:

https://www.qubes-os.org/security/verifying-signatures/

Leo Famulari:
> On Wed, Apr 07, 2021 at 05:42:40AM +0000, bo0od wrote:
>> Hi There,
>>
>> I see there is only .sig provided:
>>
>> https://guix.gnu.org/en/download/
>>
>> Its better to provide more than one way of verification e.g:
> 
> Why?
> 

Message #14 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Carlo Zancanaro <carlo <at> zancanaro.id.au>
To: bug-guix <at> gnu.org, bo0od <bo0od <at> riseup.net>,
 Leo Famulari <leo <at> famulari.name>
Cc: 47634 <at> debbugs.gnu.org
Subject: Re: bug#47634: Accompany .asc and .DIGESTS keys for the ISO
Date: Fri, 09 Apr 2021 08:57:00 +1000

On 9 April 2021 3:34:20 am AEST, bo0od <bo0od <at> riseup.net> wrote:
>This is nicely written by Qubes documentation:
>
>https://www.qubes-os.org/security/verifying-signatures/

From that page:

> If you’ve already verified the signatures on the ISO directly, then verifying digests is not necessary.

Which implies that the signatures are sufficient, right?

What is the benefit to providing the key (.asc) and hashes (.DIGESTS)? The page you linked provides rationale for providing and checking digital signatures, but we already provide them.

Carlo

Message #20 received at submit <at> debbugs.gnu.org (full text, mbox):

From: bo0od <bo0od <at> riseup.net>
To: Carlo Zancanaro <carlo <at> zancanaro.id.au>, bug-guix <at> gnu.org,
 Leo Famulari <leo <at> famulari.name>
Cc: 47634 <at> debbugs.gnu.org
Subject: Re: bug#47634: Accompany .asc and .DIGESTS keys for the ISO
Date: Fri, 9 Apr 2021 22:17:47 +0000

> Which implies that the signatures are sufficient, right?

Well this is simple question but the answer is sorta deeper, So i will 
answer with yes and no:

yes signatures are sufficient but signatures with PGP has problems, In 
the suggestion above i didnt suggest to diverse the signing methods 
(like for example using signify alongside with gpg) but just adding 
extra steps better than one (more convenience to say that everything is 
going smoothly).

To understand what im talking about i suggest to read:

Why PGP on expiration time:

https://www.whonix.org/wiki/OpenPGP#Issues_with_PGP

Discussion which might consider deprecate the usage of PGP by debian:

https://wiki.debian.org/Teams/Apt/Spec/AptSign

Whonix already using signify alongside with PGP:

https://www.whonix.org/wiki/Signify

Also there are challenges to the concept itself:

https://www.whonix.org/wiki/Verifying_Software_Signatures#Conceptual_Challenges_in_Digital_Signatures_Verification



So I hope by complete reading that you will come to the conclusion that 
either provide as much as possible from extra verification (like 
.asc,DIGESTS,SHA512...etc) or provide alternative verification along 
side with the traditional one like using signify or using something like 
signify and thats it. (i think providing both methods like pgp/signify 
is the best way which suits everybody)




> 
> 
> On 9 April 2021 3:34:20 am AEST, bo0od <bo0od <at> riseup.net> wrote:
>> This is nicely written by Qubes documentation:
>>
>> https://www.qubes-os.org/security/verifying-signatures/
> 
>  From that page:
> 
>> If you’ve already verified the signatures on the ISO directly, then verifying digests is not necessary.
> 
> Which implies that the signatures are sufficient, right?
> 
> What is the benefit to providing the key (.asc) and hashes (.DIGESTS)? The page you linked provides rationale for providing and checking digital signatures, but we already provide them.
> 
> Carlo
> 

Message #26 received at 47634 <at> debbugs.gnu.org (full text, mbox):

From: Carlo Zancanaro <carlo <at> zancanaro.id.au>
To: bo0od <bo0od <at> riseup.net>
Cc: 47634 <at> debbugs.gnu.org
Subject: Re: bug#47634: Accompany .asc and .DIGESTS keys for the ISO
Date: Sat, 10 Apr 2021 12:27:32 +1000

Hi bo0od!

On Sat, Apr 10 2021, bo0od wrote:
>> Which implies that the signatures are sufficient, right?
>
> Well this is simple question but the answer is sorta deeper, So 
> i will answer with yes and no:
>
> yes signatures are sufficient but signatures with PGP has 
> problems...

I grant that this might be true, but whether or not to use PGP is 
a different issue to whether cryptographic signatures are 
sufficient to verify downloads. If we compare the projects you've 
shown as examples:

- Qubes provides hashes, PGP signatures, and a release signing 
key

- Whonix provides hashes, PGP signatures, and a release signing 
key

For verification purposes the hashes only provide transport 
integrity - they don't provide any mechanism to verify where the 
content came from, and because they're stored next to the images 
it's likely that any attacker who could manipulate the images 
could also manipulate the hashes. The signature provides a better 
guarantee that the image contains what the project intends to 
distribute (i.e. that nobody has compromised image itself). In 
this instance, the hash provides no significant additional value 
over the signature.

If we look at the Tor project (who, I hope you will agree, care 
about security), their download page[1] only provides links to PGP 
signatures as their sole method of verification.

I'm not convinced there's much value to add anything beyond the 
signatures, and I think there is some cost. Having multiple 
verification options makes the download page more confusing (by 
providing more choices to do the same thing), and may make it less 
likely that people do any verification.

I think there may be a larger conversation to have around using 
something like Signify rather than PGP/GPG, but I'm not familiar 
enough with Signify to have an opinion about that at the moment.

Carlo

[1]: https://www.torproject.org/download/

Message #29 received at 47634 <at> debbugs.gnu.org (full text, mbox):

From: bo0od <bo0od <at> riseup.net>
To: Carlo Zancanaro <carlo <at> zancanaro.id.au>
Cc: 47634 <at> debbugs.gnu.org
Subject: Re: bug#47634: Accompany .asc and .DIGESTS keys for the ISO
Date: Sat, 10 Apr 2021 21:24:13 +0000

> In this instance, the hash provides no
> significant additional value over the signature.

What you said is true, Only thing i would see it useful when there is an 
attack on PGP but not necessary can be produced as well on the same time 
on SHA512 like collision attack or so (nothing at the moment discovered 
but just theoretical attack)

> If we look at the Tor project (who, I hope you will agree, care about
> security), their download page[1] only provides links to PGP signatures
> as their sole method of verification.

If you tell me what most projects using at the moment i would tell you 
straight forward PGP, But on the future bases PGP on the bye bye way so 
what im suggesting here is to make it happen now rather than just 
waiting for the future to come with its more insecurities. (like what i 
referred to debian deprecation of PGP)

> I think there may be a larger conversation to have around using
> something like Signify rather than PGP/GPG, but I'm not familiar enough
> with Signify to have an opinion about that at the moment.

Sure tyt, These stuff doesnt need to be fixed instantly but need to be 
looked in for sure.

ThX!

Carlo Zancanaro:
> Hi bo0od!
> 
> On Sat, Apr 10 2021, bo0od wrote:
>>> Which implies that the signatures are sufficient, right?
>>
>> Well this is simple question but the answer is sorta deeper, So i will 
>> answer with yes and no:
>>
>> yes signatures are sufficient but signatures with PGP has problems...
> 
> I grant that this might be true, but whether or not to use PGP is a 
> different issue to whether cryptographic signatures are sufficient to 
> verify downloads. If we compare the projects you've shown as examples:
> 
> - Qubes provides hashes, PGP signatures, and a release signing key
> 
> - Whonix provides hashes, PGP signatures, and a release signing key
> 
> For verification purposes the hashes only provide transport integrity - 
> they don't provide any mechanism to verify where the content came from, 
> and because they're stored next to the images it's likely that any 
> attacker who could manipulate the images could also manipulate the 
> hashes. The signature provides a better guarantee that the image 
> contains what the project intends to distribute (i.e. that nobody has 
> compromised image itself). In this instance, the hash provides no 
> significant additional value over the signature.
> 
> If we look at the Tor project (who, I hope you will agree, care about 
> security), their download page[1] only provides links to PGP signatures 
> as their sole method of verification.
> 
> I'm not convinced there's much value to add anything beyond the 
> signatures, and I think there is some cost. Having multiple verification 
> options makes the download page more confusing (by providing more 
> choices to do the same thing), and may make it less likely that people 
> do any verification.
> 
> I think there may be a larger conversation to have around using 
> something like Signify rather than PGP/GPG, but I'm not familiar enough 
> with Signify to have an opinion about that at the moment.
> 
> Carlo
> 
> [1]: https://www.torproject.org/download/

Message #32 received at 47634 <at> debbugs.gnu.org (full text, mbox):

From: Ludovic Courtès <ludo <at> gnu.org>
To: Carlo Zancanaro <carlo <at> zancanaro.id.au>
Cc: bo0od <bo0od <at> riseup.net>, 47634 <at> debbugs.gnu.org
Subject: Re: bug#47634: Accompany .asc and .DIGESTS keys for the ISO
Date: Sun, 18 Apr 2021 12:40:10 +0200

Hi all,

Carlo Zancanaro <carlo <at> zancanaro.id.au> skribis:

> I'm not convinced there's much value to add anything beyond the
> signatures, and I think there is some cost. Having multiple 
> verification options makes the download page more confusing (by
> providing more choices to do the same thing), and may make it less 
> likely that people do any verification.

Agreed.

> I think there may be a larger conversation to have around using
> something like Signify rather than PGP/GPG, but I'm not familiar 
> enough with Signify to have an opinion about that at the moment.

Right.  OpenPGP isn’t great for software signing, but it’s widespread,
and that’s an important criterion if we are to allow users to
authenticate what they download.  Tools like Signify are certainly worth
looking at, but I see it as a longer-term option.

I’m closing this issue since it’s not really actionable.

Thanks,
Ludo’.

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