SHA-1 vs SHA256 + public key

[Mark Rijckenberg]

Hi,

I noticed that your team still distributes SHA-1 checksums for the .iso images for guix at – for example – the following URL:

https://lists.gnu.org/archive/html/guix-devel/2017-05/msg00379.html

May I kindly ask you to take a look at the following links?

https://en.wikipedia.org/wiki/Secure_Hash_Algorithms

gobolinux/LiveCD#8

MD5, SHA-0 and SHA1 are all vulnerable to collision attacks.

SHA256 (or SHA512) is now the standard (for the moment).

I highly recommend dropping the use of MD5 (and dropping SHA-1) and replacing it with only SHA256 (or SHA512).

I am simply using Qubes OS as an excellent point of reference, which uses SHA256 and SHA512.

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

https://www.qubes-os.org/downloads/

Concerning the use of Bittorrent, could you please read this?

https://www.ghacks.net/2016/02/21/linux-mint-hacked-iso-images-compromised/

If you put the .iso image and corresponding SHA256 checksum file, signature and PGP/public key in a .zip file and distribute it immediately via Bittorrent BEFORE hosting it on a website, hackers will probably not be able to compromise the integrity of the .iso image, because the SHA256 checksum in the Bittorrent file is much harder to alter than one stored on a website. Furthermore, you then have the option of comparing the SHA256 value in the .torrent file with the value on the website. This goes even further than what most GNU/Linux distributions actually do….

“The reason is simple; popular torrents are distributed from several seeders and peers, and once they are in circulation, it is not possible to manipulate the data, say replace it with a hacked image.”

I also suggest putting all this information (iso image, SHA256 checksum file, signature and PGP/public key) into a single location, for example here to make it more visible to everybody:

https://www.gnu.org/software/guix/download/

Kind regards,

Mark Rijckenberg

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IRC chat history this evening:

[19:56] == Ulysses_address@hidden/web/freenode/ip.62.235.83.36] has joined #guix

...

[20:00] <Ulysses_> Hi! Are any of the guix webadministrators who post the iso image and signature file online, present?

[20:01] <mbakke> Ulysses_: Both maintainers seem to be afk at the moment. Why do you ask?

[20:04] <Ulysses_> I would like to know if it would be possible to put the SHA256 and SHA512 Checksums, a PGP key and signature file next to each posted .iso image, the same way that Qubes OS does? Even better would be to put it all in a zipped torrent file..... What do you think?

[20:04] == retardaddress@hidden/web/freenode/ip.50.38.120.92] has joined #guix

[20:04] <retard> Anyone here?

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[20:06] == brendyyn [~address@hidden] has quit [Ping timeout: 268 seconds]

[20:07] <mbakke> Ulysses_: the signatures are already there on the download page, and SHA1(!) checksums are posted in the release announcement

[20:07] <solene> Ulysses_: there is a mail with sig files links and the checksums

[20:07] <mbakke> oh, you meant the actual public key

[20:08] <Ulysses_> MD5, SHA-0 and SHA1 are all vulnerable to collision attacks...

[20:09] <Ulysses_> take a look at the Qubes OS website here (as an example) : https://www.qubes-os.org/downloads/

[20:09] <Ulysses_> SHA256 and above are not (yet) vulnerable to collision attacks....

[20:09] <mbakke> Ulysses_: the public keys can be downloaded from Savannah, but I agree they could be more visible

[20:10] <mbakke> can you send a message to address@hidden about this?

[20:10] <Ulysses_> OK will do :-)