x25519.h File Reference

RFC 7748 X25519: scalar multiplication on Curve25519 for ECDHE. More...

#include "common/platform/sys/syscall.h"

Go to the source code of this file.

Macros
#define	X25519_LEN   32
	X25519 scalar / u-coordinate length in bytes.

Functions
int	wired_x25519 (u8 out[X25519_LEN], const u8 scalar[X25519_LEN], const u8 point[X25519_LEN])
	out = scalar * point on Curve25519.
int	wired_x25519_base (u8 out[X25519_LEN], const u8 scalar[X25519_LEN])
	out = scalar * base point (9).

Detailed Description

RFC 7748 X25519: scalar multiplication on Curve25519 for ECDHE.

Function Documentation

wired_x25519()

int wired_x25519	(	u8	out[X25519_LEN],
		const u8	scalar[X25519_LEN],
		const u8	point[X25519_LEN] )

out = scalar * point on Curve25519.

scalar and point are 32-byte little-endian; out is the 32-byte little-endian u-coordinate.

Parameters

out	receives the u-coordinate of the product
scalar	the 32-byte little-endian scalar
point	the 32-byte little-endian u-coordinate to multiply

Returns

RFC 7748 6.1: 0 if the result is all-zero (low-order point), 1 otherwise. Callers MUST reject a 0 return (contributory behaviour).

wired_x25519_base()

int wired_x25519_base	(	u8	out[X25519_LEN],
		const u8	scalar[X25519_LEN] )

out = scalar * base point (9).

Produces an X25519 public key.

Parameters

out	receives the public key
scalar	the 32-byte little-endian scalar

Returns

1 (a public key is never all-zero); typed int for a uniform API.