Javascript implementation of the Curve25519 elliptic cryptography function by Daniel J. Bernstein.
Synopsis:
var my_public_key = curve25519(my_secret);
var shared_secret = curve25519(my_secret, public_key);As in curve25519-donna, some bits in the private key are altered to harden the operation of the function. If you need the private key to be unmodified for your protocol, use curve25519_raw(private_key, public_key).
Private and public keys are represented by arrays of 16-bit values, starting from the least significant ones:
key = arr[0] + arr[1] × 2^16 + arr[2] × 2^32 + … + arr[15] × 2^(16 × 15)
Please note that, while the main function is free of conditional branching, its actual constant-time operation is dependent on the Javascript implementation of numerical operations being also constant-time.
For consistency and conformance testing, you can run the script test-curve25519.coffee under tests/
The output should be identical to test-curve25519.c from the reference
implementation: http://cr.yp.to/ecdh/curve25519-20050915.tar.gz
Among the contributors, in no particular order:
Graydon Hoare: suggested clamping the private key by default for increased safety and uniformity with other implementations.
liliakai: spotted an unused argument in some of the functions
RyanC: removed dependency of a function to the Javascript Math library
Guy Kloss: performance improvements through bit-shift operations
maxrmp: reported about the support of full 256-bit public keys
If you are one of the contributors and want to add yourself or change the information here, please do submit a pull request.
Copyright (c) 2007, 2013, 2014 Michele Bini
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