ParagonIE_Sodium_Core32_Curve25519::fe_tobytes

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Summery Summery

Convert a field element to a byte string.

Syntax Syntax

ParagonIE_Sodium_Core32_Curve25519::fe_tobytes( ParagonIE_Sodium_Core32_Curve25519_Fe $h )

Parameters Parameters

$h

(ParagonIE_Sodium_Core32_Curve25519_Fe) (Required)

Return Return

(string)

Source Source

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

    public static function fe_tobytes(ParagonIE_Sodium_Core32_Curve25519_Fe $h)
    {
        /**
         * @var ParagonIE_Sodium_Core32_Int64[] $f
         * @var ParagonIE_Sodium_Core32_Int64 $q
         */
        $f = array();

        for ($i = 0; $i < 10; ++$i) {
            $f[$i] = $h[$i]->toInt64();
        }

        $q = $f[9]->mulInt(19, 5)->addInt(1 << 14)->shiftRight(25)
            ->addInt64($f[0])->shiftRight(26)
            ->addInt64($f[1])->shiftRight(25)
            ->addInt64($f[2])->shiftRight(26)
            ->addInt64($f[3])->shiftRight(25)
            ->addInt64($f[4])->shiftRight(26)
            ->addInt64($f[5])->shiftRight(25)
            ->addInt64($f[6])->shiftRight(26)
            ->addInt64($f[7])->shiftRight(25)
            ->addInt64($f[8])->shiftRight(26)
            ->addInt64($f[9])->shiftRight(25);

        $f[0] = $f[0]->addInt64($q->mulInt(19, 5));

        $carry0 = $f[0]->shiftRight(26);
        $f[1] = $f[1]->addInt64($carry0);
        $f[0] = $f[0]->subInt64($carry0->shiftLeft(26));

        $carry1 = $f[1]->shiftRight(25);
        $f[2] = $f[2]->addInt64($carry1);
        $f[1] = $f[1]->subInt64($carry1->shiftLeft(25));

        $carry2 = $f[2]->shiftRight(26);
        $f[3] = $f[3]->addInt64($carry2);
        $f[2] = $f[2]->subInt64($carry2->shiftLeft(26));

        $carry3 = $f[3]->shiftRight(25);
        $f[4] = $f[4]->addInt64($carry3);
        $f[3] = $f[3]->subInt64($carry3->shiftLeft(25));

        $carry4 = $f[4]->shiftRight(26);
        $f[5] = $f[5]->addInt64($carry4);
        $f[4] = $f[4]->subInt64($carry4->shiftLeft(26));

        $carry5 = $f[5]->shiftRight(25);
        $f[6] = $f[6]->addInt64($carry5);
        $f[5] = $f[5]->subInt64($carry5->shiftLeft(25));

        $carry6 = $f[6]->shiftRight(26);
        $f[7] = $f[7]->addInt64($carry6);
        $f[6] = $f[6]->subInt64($carry6->shiftLeft(26));

        $carry7 = $f[7]->shiftRight(25);
        $f[8] = $f[8]->addInt64($carry7);
        $f[7] = $f[7]->subInt64($carry7->shiftLeft(25));

        $carry8 = $f[8]->shiftRight(26);
        $f[9] = $f[9]->addInt64($carry8);
        $f[8] = $f[8]->subInt64($carry8->shiftLeft(26));

        $carry9 = $f[9]->shiftRight(25);
        $f[9] = $f[9]->subInt64($carry9->shiftLeft(25));

        /** @var int $h0 */
        $h0 = $f[0]->toInt32()->toInt();
        /** @var int $h1 */
        $h1 = $f[1]->toInt32()->toInt();
        /** @var int $h2 */
        $h2 = $f[2]->toInt32()->toInt();
        /** @var int $h3 */
        $h3 = $f[3]->toInt32()->toInt();
        /** @var int $h4 */
        $h4 = $f[4]->toInt32()->toInt();
        /** @var int $h5 */
        $h5 = $f[5]->toInt32()->toInt();
        /** @var int $h6 */
        $h6 = $f[6]->toInt32()->toInt();
        /** @var int $h7 */
        $h7 = $f[7]->toInt32()->toInt();
        /** @var int $h8 */
        $h8 = $f[8]->toInt32()->toInt();
        /** @var int $h9 */
        $h9 = $f[9]->toInt32()->toInt();

        /**
         * @var array<int, int>
         */
        $s = array(
            (int) (($h0 >> 0) & 0xff),
            (int) (($h0 >> 8) & 0xff),
            (int) (($h0 >> 16) & 0xff),
            (int) ((($h0 >> 24) | ($h1 << 2)) & 0xff),
            (int) (($h1 >> 6) & 0xff),
            (int) (($h1 >> 14) & 0xff),
            (int) ((($h1 >> 22) | ($h2 << 3)) & 0xff),
            (int) (($h2 >> 5) & 0xff),
            (int) (($h2 >> 13) & 0xff),
            (int) ((($h2 >> 21) | ($h3 << 5)) & 0xff),
            (int) (($h3 >> 3) & 0xff),
            (int) (($h3 >> 11) & 0xff),
            (int) ((($h3 >> 19) | ($h4 << 6)) & 0xff),
            (int) (($h4 >> 2) & 0xff),
            (int) (($h4 >> 10) & 0xff),
            (int) (($h4 >> 18) & 0xff),
            (int) (($h5 >> 0) & 0xff),
            (int) (($h5 >> 8) & 0xff),
            (int) (($h5 >> 16) & 0xff),
            (int) ((($h5 >> 24) | ($h6 << 1)) & 0xff),
            (int) (($h6 >> 7) & 0xff),
            (int) (($h6 >> 15) & 0xff),
            (int) ((($h6 >> 23) | ($h7 << 3)) & 0xff),
            (int) (($h7 >> 5) & 0xff),
            (int) (($h7 >> 13) & 0xff),
            (int) ((($h7 >> 21) | ($h8 << 4)) & 0xff),
            (int) (($h8 >> 4) & 0xff),
            (int) (($h8 >> 12) & 0xff),
            (int) ((($h8 >> 20) | ($h9 << 6)) & 0xff),
            (int) (($h9 >> 2) & 0xff),
            (int) (($h9 >> 10) & 0xff),
            (int) (($h9 >> 18) & 0xff)
        );
        return self::intArrayToString($s);
    }

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