ParagonIE_Sodium_Core32_Curve25519::ge_double_scalarmult_vartime

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Syntax Syntax

ParagonIE_Sodium_Core32_Curve25519::ge_double_scalarmult_vartime( string $a, ParagonIE_Sodium_Core32_Curve25519_Ge_P3 $A, string $b )

Parameters Parameters

$a

(Required)

$A

(Required)

$b

(Required)

Return Return

(ParagonIE_Sodium_Core32_Curve25519_Ge_P2)

Source Source

File: wp-includes/sodium_compat/src/Core32/Curve25519.php

    public static function ge_double_scalarmult_vartime(
        $a,
        ParagonIE_Sodium_Core32_Curve25519_Ge_P3 $A,
        $b
    ) {
        /** @var array<int, ParagonIE_Sodium_Core32_Curve25519_Ge_Cached> $Ai */
        $Ai = array();

        static $Bi = array();
        /** @var array<int, ParagonIE_Sodium_Core32_Curve25519_Ge_Precomp> $Bi */
        if (!$Bi) {
            for ($i = 0; $i < 8; ++$i) {
                $Bi[$i] = new ParagonIE_Sodium_Core32_Curve25519_Ge_Precomp(
                    ParagonIE_Sodium_Core32_Curve25519_Fe::fromArray(
                        array(
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][0][0]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][0][1]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][0][2]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][0][3]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][0][4]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][0][5]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][0][6]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][0][7]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][0][8]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][0][9])
                        )
                    ),
                    ParagonIE_Sodium_Core32_Curve25519_Fe::fromArray(
                        array(
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][1][0]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][1][1]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][1][2]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][1][3]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][1][4]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][1][5]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][1][6]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][1][7]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][1][8]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][1][9])
                        )
                    ),
                    ParagonIE_Sodium_Core32_Curve25519_Fe::fromArray(
                        array(
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][2][0]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][2][1]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][2][2]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][2][3]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][2][4]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][2][5]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][2][6]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][2][7]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][2][8]),
                            ParagonIE_Sodium_Core32_Int32::fromInt(self::$base2[$i][2][9])
                        )
                    )
                );
            }
        }

        for ($i = 0; $i < 8; ++$i) {
            $Ai[$i] = new ParagonIE_Sodium_Core32_Curve25519_Ge_Cached(
                self::fe_0(),
                self::fe_0(),
                self::fe_0(),
                self::fe_0()
            );
        }
        /** @var array<int, ParagonIE_Sodium_Core32_Curve25519_Ge_Cached> $Ai */

        # slide(aslide,a);
        # slide(bslide,b);
        /** @var array<int, int> $aslide */
        $aslide = self::slide($a);
        /** @var array<int, int> $bslide */
        $bslide = self::slide($b);

        # ge_p3_to_cached(&Ai[0],A);
        # ge_p3_dbl(&t,A); ge_p1p1_to_p3(&A2,&t);
        $Ai[0] = self::ge_p3_to_cached($A);
        $t = self::ge_p3_dbl($A);
        $A2 = self::ge_p1p1_to_p3($t);

        # ge_add(&t,&A2,&Ai[0]); ge_p1p1_to_p3(&u,&t); ge_p3_to_cached(&Ai[1],&u);
        # ge_add(&t,&A2,&Ai[1]); ge_p1p1_to_p3(&u,&t); ge_p3_to_cached(&Ai[2],&u);
        # ge_add(&t,&A2,&Ai[2]); ge_p1p1_to_p3(&u,&t); ge_p3_to_cached(&Ai[3],&u);
        # ge_add(&t,&A2,&Ai[3]); ge_p1p1_to_p3(&u,&t); ge_p3_to_cached(&Ai[4],&u);
        # ge_add(&t,&A2,&Ai[4]); ge_p1p1_to_p3(&u,&t); ge_p3_to_cached(&Ai[5],&u);
        # ge_add(&t,&A2,&Ai[5]); ge_p1p1_to_p3(&u,&t); ge_p3_to_cached(&Ai[6],&u);
        # ge_add(&t,&A2,&Ai[6]); ge_p1p1_to_p3(&u,&t); ge_p3_to_cached(&Ai[7],&u);
        for ($i = 0; $i < 7; ++$i) {
            $t = self::ge_add($A2, $Ai[$i]);
            $u = self::ge_p1p1_to_p3($t);
            $Ai[$i + 1] = self::ge_p3_to_cached($u);
        }

        # ge_p2_0(r);
        $r = self::ge_p2_0();

        # for (i = 255;i >= 0;--i) {
        #     if (aslide[i] || bslide[i]) break;
        # }
        $i = 255;
        for (; $i >= 0; --$i) {
            if ($aslide[$i] || $bslide[$i]) {
                break;
            }
        }

        # for (;i >= 0;--i) {
        for (; $i >= 0; --$i) {
            # ge_p2_dbl(&t,r);
            $t = self::ge_p2_dbl($r);

            # if (aslide[i] > 0) {
            if ($aslide[$i] > 0) {
                # ge_p1p1_to_p3(&u,&t);
                # ge_add(&t,&u,&Ai[aslide[i]/2]);
                $u = self::ge_p1p1_to_p3($t);
                $t = self::ge_add(
                    $u,
                    $Ai[(int) floor($aslide[$i] / 2)]
                );
                # } else if (aslide[i] < 0) {
            } elseif ($aslide[$i] < 0) {
                # ge_p1p1_to_p3(&u,&t);
                # ge_sub(&t,&u,&Ai[(-aslide[i])/2]);
                $u = self::ge_p1p1_to_p3($t);
                $t = self::ge_sub(
                    $u,
                    $Ai[(int) floor(-$aslide[$i] / 2)]
                );
            }
            /** @var array<int, ParagonIE_Sodium_Core32_Curve25519_Ge_Precomp> $Bi */

            # if (bslide[i] > 0) {
            if ($bslide[$i] > 0) {
                # ge_p1p1_to_p3(&u,&t);
                # ge_madd(&t,&u,&Bi[bslide[i]/2]);
                $u = self::ge_p1p1_to_p3($t);
                /** @var int $index */
                $index = (int) floor($bslide[$i] / 2);
                /** @var ParagonIE_Sodium_Core32_Curve25519_Ge_Precomp $thisB */
                $thisB = $Bi[$index];
                $t = self::ge_madd($t, $u, $thisB);
                # } else if (bslide[i] < 0) {
            } elseif ($bslide[$i] < 0) {
                # ge_p1p1_to_p3(&u,&t);
                # ge_msub(&t,&u,&Bi[(-bslide[i])/2]);
                $u = self::ge_p1p1_to_p3($t);

                /** @var int $index */
                $index = (int) floor(-$bslide[$i] / 2);

                /** @var ParagonIE_Sodium_Core32_Curve25519_Ge_Precomp $thisB */
                $thisB = $Bi[$index];
                $t = self::ge_msub($t, $u, $thisB);
            }
            # ge_p1p1_to_p2(r,&t);
            $r = self::ge_p1p1_to_p2($t);
        }
        return $r;
    }

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