16238255757

Committed 12 Jul 2025 01:00PM UTC coverage: 84.857% (-6.3%) from 91.134%

Build # 16238255757

Build Type

Pull #12

github

Committed by

web-flow

Commit Message

Merge 97611838a into 5ce1049c0

Pull Request Pull Request #12: WIP: Add montgomery

Run Details

270 of 376 new or added lines in 17 files covered. (71.81%)

2 existing lines in 1 file now uncovered.

947 of 1116 relevant lines covered (84.86%)

23.02 hits per line

Source File
Press 'n' to go to next uncovered line, 'b' for previous

98.68

/src/Math/Calculator/Adder/MGUnsafeAdder.php

<?php

/** @noinspection DuplicatedCode */

namespace Famoser\Elliptic\Math\Calculator\Adder;

use Famoser\Elliptic\Primitives\Point;

/**
 * Implements algorithms proposed in https://www.hyperelliptic.org/EFD/g1p/auto-montgom.html
 * Merged with rules for edge-cases from https://www.secg.org/SEC1-Ver-1.0.pdf (2.2.1)
 */
trait MGUnsafeAdder
{
    public function add(Point $a, Point $b): Point
    {
        // rule 1 & 2
        if ($a->isInfinity()) {
            return clone $b;
        } elseif ($b->isInfinity()) {
            return clone $a;
        }

        if (gmp_cmp($a->x, $b->x) === 0) {
            // rule 3
            if (gmp_cmp($b->y, $a->y) !== 0) {
                return Point::createInfinity();
            }

            // rule 5
            return $this->double($a);
        }

        // rule 4 (note that a / b = a * b^-1)
        $lambda = $this->field->mul(
            gmp_sub($b->y, $a->y),
            /** @phpstan-ignore-next-line invert may return false; then this will crash (which is OK, because cannot recover anyway) */
            $this->field->invert(gmp_sub($b->x, $a->x))
        );

        $x = $this->field->sub(
            gmp_sub(
                gmp_sub(
                    gmp_mul(
                        $this->curve->getB(),
                        gmp_pow($lambda, 2)
                    ),
                    $this->curve->getA()
                ),
                $a->x
            ),
            $b->x
        );

        $y = $this->field->sub(
            gmp_mul(
                $lambda,
                gmp_sub($a->x, $x)
            ),
            $a->y
        );

        return new Point($x, $y);
    }

    public function double(Point $a): Point
    {
        if (gmp_cmp($a->y, 0) === 0) {
            return Point::createInfinity();
        }

        // rule 5 (note that a / b = a * b^-1)
        $lambda = $this->field->mul(
            gmp_add(
                gmp_add(
                    gmp_mul(
                        gmp_init(3),
                        gmp_pow($a->x, 2)
                    ),
                    gmp_mul(
                        gmp_mul(2, $this->curve->getA()),
                        $a->x
                    )
                ),
                1
            ),
            /** @phpstan-ignore-next-line invert may return false; then this will crash (which is OK, because cannot recover anyway) */
            $this->field->invert(
                gmp_mul(
                    gmp_mul(2, $this->curve->getB()),
                    $a->y
                )
            )
        );

        $x = $this->field->sub(
            gmp_sub(
                gmp_mul(
                    $this->curve->getB(),
                    gmp_pow($lambda, 2)
                ),
                $this->curve->getA()
            ),
            gmp_mul(2, $a->x)
        );

        $y = $this->field->sub(
            gmp_mul(
                $lambda,
                gmp_sub($a->x, $x)
            ),
            $a->y
        );

        return new Point($x, $y);
    }
}

1	<?php
2
3	/** @noinspection DuplicatedCode */
4
5	namespace Famoser\Elliptic\Math\Calculator\Adder;
6
7	use Famoser\Elliptic\Primitives\Point;
8
9	/**
10	* Implements algorithms proposed in https://www.hyperelliptic.org/EFD/g1p/auto-montgom.html
11	* Merged with rules for edge-cases from https://www.secg.org/SEC1-Ver-1.0.pdf (2.2.1)
12	*/
13	trait MGUnsafeAdder
14	{
15	public function add(Point $a, Point $b): Point	3✔
16	{
17	// rule 1 & 2
18	if ($a->isInfinity()) {	3✔
19	return clone $b;	2✔
20	} elseif ($b->isInfinity()) {	3✔
21	return clone $a;	2✔
22	}
23
24	if (gmp_cmp($a->x, $b->x) === 0) {	3✔
25	// rule 3
26	if (gmp_cmp($b->y, $a->y) !== 0) {	1✔
NEW 27	return Point::createInfinity();	×
28	}
29
30	// rule 5
31	return $this->double($a);	1✔
32	}
33
34	// rule 4 (note that a / b = a * b^-1)
35	$lambda = $this->field->mul(	2✔
36	gmp_sub($b->y, $a->y),	2✔
37	/** @phpstan-ignore-next-line invert may return false; then this will crash (which is OK, because cannot recover anyway) */
38	$this->field->invert(gmp_sub($b->x, $a->x))	2✔
39	);	2✔
40
41	$x = $this->field->sub(	2✔
42	gmp_sub(	2✔
43	gmp_sub(	2✔
44	gmp_mul(	2✔
45	$this->curve->getB(),	2✔
46	gmp_pow($lambda, 2)	2✔
47	),	2✔
48	$this->curve->getA()	2✔
49	),	2✔
50	$a->x	2✔
51	),	2✔
52	$b->x	2✔
53	);	2✔
54
55	$y = $this->field->sub(	2✔
56	gmp_mul(	2✔
57	$lambda,	2✔
58	gmp_sub($a->x, $x)	2✔
59	),	2✔
60	$a->y	2✔
61	);	2✔
62
63	return new Point($x, $y);	2✔
64	}
65
66	public function double(Point $a): Point	4✔
67	{
68	if (gmp_cmp($a->y, 0) === 0) {	4✔
69	return Point::createInfinity();	2✔
70	}
71
72	// rule 5 (note that a / b = a * b^-1)
73	$lambda = $this->field->mul(	4✔
74	gmp_add(	4✔
75	gmp_add(	4✔
76	gmp_mul(	4✔
77	gmp_init(3),	4✔
78	gmp_pow($a->x, 2)	4✔
79	),	4✔
80	gmp_mul(	4✔
81	gmp_mul(2, $this->curve->getA()),	4✔
82	$a->x	4✔
83	)	4✔
84	),	4✔
85	1	4✔
86	),	4✔
87	/** @phpstan-ignore-next-line invert may return false; then this will crash (which is OK, because cannot recover anyway) */
88	$this->field->invert(	4✔
89	gmp_mul(	4✔
90	gmp_mul(2, $this->curve->getB()),	4✔
91	$a->y	4✔
92	)	4✔
93	)	4✔
94	);	4✔
95
96	$x = $this->field->sub(	4✔
97	gmp_sub(	4✔
98	gmp_mul(	4✔
99	$this->curve->getB(),	4✔
100	gmp_pow($lambda, 2)	4✔
101	),	4✔
102	$this->curve->getA()	4✔
103	),	4✔
104	gmp_mul(2, $a->x)	4✔
105	);	4✔
106
107	$y = $this->field->sub(	4✔
108	gmp_mul(	4✔
109	$lambda,	4✔
110	gmp_sub($a->x, $x)	4✔
111	),	4✔
112	$a->y	4✔
113	);	4✔
114
115	return new Point($x, $y);	4✔
116	}
117	}

famoser / elliptic / 16238255757

Source File Press 'n' to go to next uncovered line, 'b' for previous

Source File
Press 'n' to go to next uncovered line, 'b' for previous