A process using curl (rtorrent) was giving the subject error after the remote system updated their secure cert from SHA1 to SHA256.
this page provides an answer; openssl needs to be updated: “It requires at least OpenSSL 0.9.8o for a total management of SHA256”
On top of that, (on Ubuntu jaunty) curl needed to be installed from source and the libcurl libraries were updated to get this working again.