Thanks to mdeslaur for finding that the _root_ cert is the problem, not mine, nor a code problem with gnutls:
http://blog.cacert.org/2015/12/re-signing-root-certificate/ ** Changed in: gnutls26 (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1532911 Title: [regression] 2.12.23-12ubuntu2.4 breaks sha512 certificates To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnutls26/+bug/1532911/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
