From the course: Cisco Network Security: Core Security Concepts
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Key exchange - Cisco Tutorial
From the course: Cisco Network Security: Core Security Concepts
Key exchange
- [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, DDDES, 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, as the…
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