[HN Gopher] A Vulnerability in Libsodium
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       A Vulnerability in Libsodium
        
       Author : raggi
       Score  : 144 points
       Date   : 2025-12-30 17:24 UTC (5 hours ago)
        
 (HTM) web link (00f.net)
 (TXT) w3m dump (00f.net)
        
       | CiPHPerCoder wrote:
       | This also affected the PHP library, sodium_compat.
       | https://github.com/FriendsOfPHP/security-advisories/pull/756
       | 
       | I'm planning to spend my evening checking every other Ed25519
       | implementation I can find to see if this check is missing any
       | where else in the open source ecosystem.
        
         | hu3 wrote:
         | Thank you for your work on open source.
        
         | CiPHPerCoder wrote:
         | I found several libraries that simply didn't implement the
         | check, but none that implemented in incorrectly in the same way
         | as the vulnerability discussed above.
         | 
         | If you didn't receive an email from me, either your
         | implementation isn't listed on
         | https://ianix.com/pub/ed25519-deployment.html, I somehow missed
         | it, or you're safe.
        
       | proof_by_vibes wrote:
       | I've been iterating on sodium bindings in Lean4 for about four
       | months, and now that I've gotten to Ristretto255 I can see why
       | the author is excited about its potential. Ristretto is a tightly
       | designed API that allows me to build arbitrary polynomials on
       | Curve25519 and I've been having a blast tinkering and
       | experimenting with it! If the author by chance reads this, just
       | want to say thank you for your work!
        
         | fshacf wrote:
         | You have a public repo of this?
        
       | gafferongames wrote:
       | Such a great library. Thank you Frank Denis
        
       | theLiminator wrote:
       | If you work for a big company, consider trying to get Frank
       | sponsored by your company.
        
         | guessmyname wrote:
         | I work for a big company (Apple) but I have no idea who Frank
         | is, nor how to sponsor them; and even if I knew them and how to
         | sponsor them, the money would come directly from my pocket
         | instead of Apple's banking account.
        
           | CiPHPerCoder wrote:
           | From the article:                 If libsodium is useful to
           | you, please keep in mind that it is maintained by one person,
           | for free, in time I could spend with my family or on other
           | projects. The best way to help the project would be to
           | consider sponsoring it, which helps me dedicate more time to
           | improving it and making it great for everyone, for many more
           | years to come.
           | 
           | The "sponsoring it" links to
           | https://opencollective.com/libsodium/contribute
           | 
           | Hope that helps.
        
             | FiloSottile wrote:
             | Frank does great work that is critical to many businesses,
             | and should get funded to do it professionally.
             | 
             | However, donating money to an open collective is
             | prohibitively hard for most big companies. Maybe the world
             | should be different (or maybe not, since it would be easy
             | for employees to embezzle money if they could direct
             | donations easily), but that's how it works currently.
             | 
             | AFAICT, there is also no fiscal sponsor, so the donation
             | matching suggested in a sister comment won't apply.
             | 
             | This is why Geomys (https://geomys.org) works the way it
             | does, and why it has revenue (ignoring the FIPS and tlog
             | sides of the business) which is 30-50x of some GitHub
             | Sponsors "success stories": we bill in a way that's
             | compatible with how companies do business, even if
             | effectively we provide a similar service (which is 95%
             | focused on upstream maintenance, not customer support).
             | 
             | I am not saying it's for everyone, or that Frank should
             | necessarily adopt this model, or that it's the only way
             | (e.g. the Zig foundation raises real amounts of money,
             | too), but I find it frustrating to see over and over again
             | the same conversation:
             | 
             | - "Alice does important maintenance work, she should get
             | professionally funded for it!"
             | 
             | - "How does Alice accept/request funding?"
             | 
             | - "Monthly credit card transactions anchored at $100/mo
             | that are labeled donations"
             | 
             | - _no business can move professional amounts of money that
             | way_
             | 
             | - "Businesses are so short-sighted, it's a tragedy of the
             | commons!"
        
           | AndyKelley wrote:
           | Maybe you don't know this but Apple has a donation-matching
           | program. If you make donations to non-profits through some
           | special internal mechanism, the company will send a donation
           | of equal value (up to some limit). If I recall correctly the
           | limit is 30K USD per person.
        
             | zenmac wrote:
             | Do you have any links or more info about the special
             | internal mechanism? Would need an apple employee to
             | initiate this I assume?
        
               | squigz wrote:
               | "When you give money to an eligible organization, we'll
               | match your donations one-for-one, so your $1 has the
               | impact of $2. And if you choose to donate your time,
               | we'll contribute $25 for every hour you volunteer.
               | Whether you donate time or money, Apple will match your
               | contributions up to $10,000 a year."
               | 
               | https://www.apple.com/careers/us/life-at-
               | apple/benefits.html
        
       | runtimepanic wrote:
       | Subtle but important bug. This is a good example of how "is
       | valid" checks in crypto are rarely as simple as they sound.
       | Accepting points outside the prime-order subgroup can quietly
       | undermine higher-level assumptions, even if no immediate exploit
       | is obvious. Also a reminder that low-level primitives tend to be
       | reused far more widely than intended, so small validation gaps
       | can have surprisingly large blast radii.
        
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