Overview#X25519 is a mathematical function that performs scalar multiplication on the Montgomery form of the Curve25519 and is defined in RFC 7748
Daniel J. Bernstein proposed:
- X25519 be the name of the Diffie-Hellman Key-Exchange protocol
- Curve25519 be the name of the Elliptic Curve
25519 indicates that the characteristic of the bottom prime number field on which the Elliptic Curve depends is 2²⁵⁵-19.
Compared with the ECDH Key-Exchange protocol, the most notable feature of the X25519 protocol is that it only depends on the x coordinate of the point on the Elliptic Curve. The idea of constructing an ECDH key exchange protocol using only x coordinates originally came from the paper published by Victor Millier in 1985, "Use of Elliptic Curves in Cryptography".
More Information#There might be more information for this subject on one of the following:
- Quick UDP Internet Connections
- RFC 8418
- TLS 1.3
- The Onion Router
- [#1] - Curve25519 - based on information obtained 2017-06-17-
- [#2] - A Deep Dive into X25519 - based on information obtained 2020-02-20
- [#3] - SECURE COMMUNICATION USING AUTHENTICATED CHANNELS - based on information obtained 2020-02-20
- [#4] - Use of Elliptic Curves in Cryptography - based on information obtained 2020-02-20