How does encryption work?

Confidential information is translated into binary before being superimposed onto a secret random encryption key by performing binary addition. The result is another random sequence of ones and zeros. Because this sequence is also random, nobody can find the confidential information hidden in it, even when analyzing the sequence. At this stage, the messages, also called cryptograms, can only be decoded with the matching key. That makes it possible to send the message safely even when using non-encrypted or public methods. Once the recipient gets the cryptogram, they can recover the confidential information hidden by subtracting the random sequence of the encryption key. Illustration: Kaori Serakaki/OIST