> From: openssl-users [mailto:openssl-users-boun...@openssl.org] On Behalf
> Of Matt Caswell
> Sent: Wednesday, September 12, 2018 14:29
>
> On 12/09/18 19:24, Chris Outwin wrote:
> > I’m an OpenSSL newbie and this is my first post. I’m using OpenSSL for
> receipt validation in an iOS application.
> >
> > Is there a list of checksums to verify openssl download versions?
>
> Next to each download on the website there are links for SHA256/PGP/SHA1
> checksums.
>
> https://www.openssl.org/source/

I'd strongly recommend verifying the PGP (OpenPGP, gpg) signature on the 
tarball. The signature files are right there alongside the tarballs.

If you're new to gpg (or whatever OpenPGP implementation of your choice), 
there's a bit of learning and setup to do: you'll need to fetch the appropriate 
key from a public keyserver or other trustworthy (-ish) source to fully verify 
the signature, and you'll probably want to mark the key as trusted so the 
output from gpg is clear.

But once you've done that, it's very easy to verify the signature, and to 
automate the process if you prefer. And the signatures add a bit of 
defense-in-depth because publishing a tampered-with tarball would require 
subverting the private key as well as to the OpenSSL web server.  (If you're 
just checking the SHA256 hash, an attacker could either get access to the 
OpenSSL web server, or force you to a counterfeit server, for example via DNS 
cache poisoning. And due to the systemic brokenness of the web PKI, it's pretty 
easy to fool a lot of people with a counterfeit server.)

So do the work now to set yourself up for verifying the signature, and 
inculcate a good habit.

--
Michael Wojcik
Distinguished Engineer, Micro Focus

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