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Current time:0:00Total duration:1:31

Video transcript

imagine two people who share an important secret have to split up this requires them to communicate private information from a distance however an eavesdropper named Eve also wants this information and has the ability to intercept their messages so Alice decides to communicate using letters written in some kind of secret code the following analogy is helpful first Alice locks her message in a box using a lock that only her and Bob know the combination to this is known as encryption then the locked message is sent to Bob when Bob receives the Box he opens it using the code they shared in advance this is called decryption cryptography begins when we abandoned physical locks and use ciphers instead think of them as virtual locks ciphers allow Alice and Bob to scramble and D scramble their messages so that they would appear meaningless if Eve intercepted them cryptography has been around for thousands of years it has decided Wars and is at the heart of the worldwide communication network today the fascinating story of cryptography requires us to understand two very old ideas related to number theory and probability theory you