ELI5: Explain Like I'm 5

SIGSALY

Sigsaly was a really important secret communication system used during World War II. Imagine you and your friend want to talk about a secret plan, but you don’t want anyone else to hear you. Sigsaly was like a really good secret code that only you and your friend could understand.

To use Sigsaly, you would use a special phone that had lots of buttons and dials on it. First, you and your friend would have to agree on a secret password so no one else can listen to your conversation. Then, you would speak into the phone and the special buttons and dials would change your voice into a secret code that nobody else can understand.

Next, your secret code voice would be sent through very special phone lines that were super secret and nobody else could access. These phone lines would take your voice code to your friend’s phone so they can hear your message.

Finally, your friend would use their special phone to turn your secret code voice back into normal words that they can understand.

Sigsaly was really important because it helped important people like leaders and generals to plan and talk about their secret war plans without the enemy finding out about them. It was like having their very own secret language that only they could understand.