Emmanuel Thomé and his colleagues at the National Institute for Research in Computer Science and Automation (Inria) have cracked the largest key so far. The team factored RSA-240, an RSA key with 240 decimal digits. The total computing time took was equivalent to a single computer core running for almost 4000 years.
https://www.newscientist.com/article/2226458-number-crunchers-set-new-record-for-cracking-online-encryption-keys/
https://www.popularmechanics.com/science/math/a30149512/longest-encryption-ever-cracked/
https://www.darkreading.com/vulnerabilities---threats/scientists-break-largest-encryption-key-yet-with-brute-force/d/d-id/1336560