The concept of a password isn't new, but its non-verbal application is a relatively modern development.

In earlier eras, passwords were typically used by sentries and soldiers and spies, wanting

to identify enemies in their midst, and to figure out when they've encountered an ally with

whom they're meant to share information or provide access rather than an enemy

hoping to trick them into divulging secrets or to let them past the heavily guarded gates.

Over time, these passwords or pass codes or signs, as they were sometimes called, became more sophisticated.

And one of the more common upgraded applications through World War II was the use of a password followed by a

counter password or a sign followed by a countersign. One person saying, for instance,

pigeon, while the other responded daffodil. And that would tell both parties they've met up

with the right person

despite not knowing each other not knowing what the other person would look like ahead of time

and so on this allowed people to create a layer of trust in an otherwise trust-free environment

and this method was improved upon with the advent of ever-changing passwords which would be

swapped out every few days to make

sure a captured soldier's password or counter-password stolen by the enemy under duress

wouldn't give them access to anything important for more than a day or two after they gave it up.

Similar trust-generating tools were used from the early days of computer networking. As a computer

network, whether we're talking about two computers directly connecting to each other over a cable,

or computers connecting via an intermediary service, like a local area network where the internet,

would want to be sure they were linking up to the correct device, lest they send information

or grant access or control to a malevolent actor,

someone wanting to hack or otherwise mess with them.

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