@Test public void toP2ReturnsExpectedResultIfGroupElementHasP3Representation() { for (int i = 0; i < 10; i++) { // Arrange: final GroupElement g = MathUtils.getRandomGroupElement(); // Act: final GroupElement h1 = g.toP2(); final GroupElement h2 = MathUtils.toRepresentation(g, GroupElement.Representation.P2); // Assert: Assert.assertThat(h1, IsEqual.equalTo(h2)); Assert.assertThat(h1.getRepresentation(), IsEqual.equalTo(GroupElement.Representation.P2)); Assert.assertThat(h1.getX(), IsEqual.equalTo(g.getX())); Assert.assertThat(h1.getY(), IsEqual.equalTo(g.getY())); Assert.assertThat(h1.getZ(), IsEqual.equalTo(g.getZ())); Assert.assertThat(h1.getT(), IsEqual.equalTo(null)); } }
@Test public void toP3ReturnsExpectedResultIfGroupElementHasP3Representation() { for (int i = 0; i < 10; i++) { // Arrange: final GroupElement g = MathUtils.getRandomGroupElement(); // Act: final GroupElement h = g.toP3(); // Assert: Assert.assertThat(h, IsEqual.equalTo(g)); Assert.assertThat(h.getRepresentation(), IsEqual.equalTo(GroupElement.Representation.P3)); Assert.assertThat(h, IsEqual.equalTo(g)); Assert.assertThat(h.getX(), IsEqual.equalTo(g.getX())); Assert.assertThat(h.getY(), IsEqual.equalTo(g.getY())); Assert.assertThat(h.getZ(), IsEqual.equalTo(g.getZ())); Assert.assertThat(h.getT(), IsEqual.equalTo(g.getT())); } }
@Test public void isOnCurveReturnsFalseForPointsNotOnTheCurve() { for (int i = 0; i < 100; i++) { // Arrange: final GroupElement g = MathUtils.getRandomGroupElement(); final GroupElement h = GroupElement.p2(curve, g.getX(), g.getY(), g.getZ().multiply(curve.getField().TWO)); // Assert (can only fail for 5*Z^2=1): Assert.assertThat(h.isOnCurve(), IsEqual.equalTo(false)); } }
@Test public void toCachedReturnsExpectedResultIfGroupElementHasP3Representation() { for (int i = 0; i < 10; i++) { // Arrange: final GroupElement g = MathUtils.getRandomGroupElement(); // Act: final GroupElement h1 = g.toCached(); final GroupElement h2 = MathUtils.toRepresentation(g, GroupElement.Representation.CACHED); // Assert: Assert.assertThat(h1, IsEqual.equalTo(h2)); Assert.assertThat( h1.getRepresentation(), IsEqual.equalTo(GroupElement.Representation.CACHED)); Assert.assertThat(h1, IsEqual.equalTo(g)); Assert.assertThat(h1.getX(), IsEqual.equalTo(g.getY().add(g.getX()))); Assert.assertThat(h1.getY(), IsEqual.equalTo(g.getY().subtract(g.getX()))); Assert.assertThat(h1.getZ(), IsEqual.equalTo(g.getZ())); Assert.assertThat(h1.getT(), IsEqual.equalTo(g.getT().multiply(curve.get2D()))); } }
@Test public void toByteArrayReturnsExpectedResult() { for (int i = 0; i < 100; i++) { // Arrange: final GroupElement g = MathUtils.getRandomGroupElement(); // Act: final byte[] gBytes = g.toByteArray(); final byte[] bytes = MathUtils.toByteArray(MathUtils.toBigInteger(g.getY())); if (MathUtils.toBigInteger(g.getX()).mod(new BigInteger("2")).equals(BigInteger.ONE)) { bytes[31] |= 0x80; } // Assert: Assert.assertThat(Arrays.equals(gBytes, bytes), IsEqual.equalTo(true)); } }