Читать книгу Introduction to Blockchain Technology - Tiana Laurence - Страница 20

The next big leap in encryption did not come until 1975 when Whitfield Diffie and Martin E. Hellman wrote a paper called “New Directions in Cryptography”. In it they described a brand-new way of encoding messages. It allowed anyone to send a secret message to another person they had not had contact with before, even without the recipient’s encryption key.

If you remember from Enigma, the encryption key was needed both to encode and decode a message. The encryption technique that Diffie and Hellman developed is commonly known as public-key cryptography or more technically “asymmetric cryptography”. It uses a pair of keys, both a public key that everyone knows so they can send you an encoded message and a private key only you know so only you can decode messages sent to you.

Asymmetric cryptography allowed, for the first time, anyone to encrypt a message using the recipient’s public key, whilst the encrypted message could only be read with the recipient’s private key. Private secure communication that we now enjoy on the internet and our phones is all possible thanks to asymmetric cryptography. It is one of the essential technologies that allows blockchain technology to exist. It also allows cryptocurrency to be sent securely from one address to another.