Encryption device for secret service
For centuries we have needed a secret code for every situation.
That's why we started to create machines to code messages for example here.
Is on this picture a disspoditife of encryption of decryption of message dating from the 17siecle.
This machine works by moving bars to transform letters into numbers, we call it polyalphabetic encryption.

Enigma
Most known, the encryption technique of the famous enigma machine.
Notably known for its use during the Second World War, it was used to encrypt many secret messages to German troops in order to organize arrests and combat.
Enigma is based on the same system as encryption device but much more complex and much more advanced.
The Enigma machine scrambles messages one letter at a time by means of a complex network of electrical wires. The operator passes an electric current through the machine by pressing a key.
Then a letter will be coded by another letter thanks to a system of rotor that turns a particular number of times according to a code that changes every day.
It is besides Turing and his team who put several years has decoded this infernal machine.
A story tells that if Turing had not succeeded in making this machine we would have lost the war.

The electronic chip
Another decryption work is that of the computer chip.
In order to be always as secure and powerful the physicists work on a new quantum technique where the cache time of some years could take some seconds today this experiment is on the right track

IBM automated teller machine
Finally, here is a street ATM allowing to retrieve account details from a central bank database without being captured by criminals who could listen to the phone lines, in 1973 the computer giant IBM developed a powerful mathematical encryption method for its frst network.
In time, this model was modifed by the Americans and has now become a worldwide standard for data security for over two decades.