The Power of Cryptography

Bitcoin and other cryptocurrencies use an array of technologies to do what was previously thought impossible. One of those technologies is cryptography.

"Cryptography" is the study and practice of secure communication. It comes the Greek word "kryptós", meaning hidden or secret, and "graphein", a word for writing. Literally translated: "Secret writing".

Cryptography has been around for millennia. The Encyclopedia of Security Management describes several techniques used by Greek armies:

"When the ancient Greeks wanted to communicate between armies separated by hostile territory, they would shave the head of a slave and tattoo the message on his scalp. When his hair grew, they would send him through the lines."

From the same book:

"One General would wrap a leather belt around a baton and write his message lengthwise along it. The messenger was given the belt to wear. The general receiving the message would wrap the belt around his batton and read the message off."

It's clever. But modern tools have gotten much, *much* better than leather and tattoos.

When people say that cryptocurrency like bitcoin is secure, they're referring to the cryptography built into the protocol. Nobody can get your coin without your "private key", or the random alpha-numeric password generated by the system. As of now, breaking just one key would take trillions of years to decipher.

This video does a fantastic job visualizing the impossible odds against anybody trying to break in.