Exchanging keys using asymmetric encryption

- [Instructor] Asymmetric encryption is great … for email confidentiality using Pretty Good Privacy … or Gnu Privacy Guard. … But for large data requirements or data transfer, … we use symmetric encryption … as it's fast, efficient, with low overhead. … Symmetric encryption uses a single shared key … to encrypt and decrypt data. … That's why most of the time we use a hybrid cryptosystem … that uses both asymmetric and symmetric encryption. … When using symmetric encryption, … such as DES, Triple DES, or AES, to exchange data, … both sides must use the same shared key. … The question is how do both sides get the same shared key? … Scientists realized this early on … and developed a way to securely transmit … the same shared secret key. … We can ensure both parties have the same shared secret key … in one of two ways, … generate keys using Diffie-Hellman … and use asymmetric encryption to transport the shared key. … Whitfield Diffie and Martin Hellman were two of a few groups … that developed public key technology in the 1970s, …