Heartbleed is the name of a critical vulnerability in the OpenSSL cryptography library. In 2014, it came under mass exploitation. Exploits let many unaffiliated hackers decrypt TLS-protected exchanges between parties. They also recovered private TLS certificate keys, session cookies, and passwords. The attacks compromised thousands of servers, some belonging to large companies and government agencies around the world. Recovery required a long series of steps that took years. Steps included patch...