Diffie-Hellman key exchange (D-H)

Diffie-Hellmankey exchange

Diffie-Hellman key exchange (D-H) is aspecific method of securely exchanging cryptographic keys over a public channeland was one of the first public-key protocols as originally conceptualized. D-His one of the earliest practical examples of public key exchange implementedwithin the field of cryptography. Traditionally, secure encrypted communicationbetween two parties required that they first exchange keys by some securephysical channel, such as paper key lists transported by a trusted courier. TheDiffie-Hellman key exchange method allows two parties that have no priorknowledge of each other to jointly establish a shared secret key over aninsecure channel. This key can then be used to encrypt subsequent communicationsusing a symmetric key cipher.