It would be unfathomable today, but for nearly 20 years, the United States nuclear launch code was probably not as strong as your email password.
According to Karl Smallwood,
In 1962 JFK signed the National Security Action Memorandum 160, which was supposed to ensure that every nuclear weapon the US had be fitted with a Permissive Action Link (PAL), basically a small device that ensured that the missile could only be launched with the right code and with the right authority.
However, though the devices were supposed to be fitted on every nuclear missile after JFK issued his memorandum, the military continually dragged its heels on the matter. In fact, it was noted that a full 20 years after JFK had order PALs be fitted to every nuclear device, half of the missiles in Europe were still protected by simple mechanical locks. Most that did have the new system in place weren’t even activated until 1977.
The military did this because they didn’t want to waste valuable potential nuking time. They also didn’t want to take a risk with a complicated password, so for almost two decades, the password to deploy the Minuteman missiles was set to 00000000.
Since the military ignored President Kennedy’s order to install the PAL system, any soldier with the code could have launched the missiles. We came a lot closer to a Dr. Strangelove type situation than anyone could have imagined.
All of this happened in the days before the Internet so the risk was level was not the same, but idea that your email is hopefully more secure today than the U.S. nuclear arsenal was at one time is still a pretty scary thought.