com.google.crypto.tink.internal

Class Curve25519

java.lang.Object

com.google.crypto.tink.internal.Curve25519

@Alpha
public final class Curve25519
extends Object

This class implements point arithmetic on the elliptic curve Curve25519.

This class only implements point arithmetic, if you want to use the ECDH Curve25519 function, please checkout X25519.

This implementation is based on curve255-donna C implementation.

Method Summary

Modifier and Type	Method and Description
static void	curveMult(long[] resultx, byte[] n, byte[] qBytes) Calculates nQ where Q is the x-coordinate of a point on the curve.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

curveMult

public static void curveMult(long[] resultx,
                             byte[] n,
                             byte[] qBytes)
                      throws InvalidKeyException

Calculates nQ where Q is the x-coordinate of a point on the curve.

Parameters:

resultx - the x projective coordinate of the resulting curve point (short form).

n - a little endian, 32-byte number.

qBytes - a little endian, 32-byte number representing the public point' x coordinate.

Throws:

InvalidKeyException - iff the public key is in the banned list or its length is not 32-byte.

IllegalStateException - iff there is arithmetic error.