ParagonIE_Sodium_Core_Curve25519::fe_tobytes

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Summery Summery

Convert a field element to a byte string.

Syntax Syntax

ParagonIE_Sodium_Core_Curve25519::fe_tobytes( ParagonIE_Sodium_Core_Curve25519_Fe $h )

Parameters Parameters

$h

(ParagonIE_Sodium_Core_Curve25519_Fe) (Required)

Return Return

(string)

Source Source

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

    public static function fe_tobytes(ParagonIE_Sodium_Core_Curve25519_Fe $h)
    {
        /** @var int $h0 */
        $h0 = (int) $h[0];
        /** @var int $h1 */
        $h1 = (int) $h[1];
        /** @var int $h2 */
        $h2 = (int) $h[2];
        /** @var int $h3 */
        $h3 = (int) $h[3];
        /** @var int $h4 */
        $h4 = (int) $h[4];
        /** @var int $h5 */
        $h5 = (int) $h[5];
        /** @var int $h6 */
        $h6 = (int) $h[6];
        /** @var int $h7 */
        $h7 = (int) $h[7];
        /** @var int $h8 */
        $h8 = (int) $h[8];
        /** @var int $h9 */
        $h9 = (int) $h[9];

        /** @var int $q */
        $q = (self::mul($h9, 19, 5) + (1 << 24)) >> 25;
        /** @var int $q */
        $q = ($h0 + $q) >> 26;
        /** @var int $q */
        $q = ($h1 + $q) >> 25;
        /** @var int $q */
        $q = ($h2 + $q) >> 26;
        /** @var int $q */
        $q = ($h3 + $q) >> 25;
        /** @var int $q */
        $q = ($h4 + $q) >> 26;
        /** @var int $q */
        $q = ($h5 + $q) >> 25;
        /** @var int $q */
        $q = ($h6 + $q) >> 26;
        /** @var int $q */
        $q = ($h7 + $q) >> 25;
        /** @var int $q */
        $q = ($h8 + $q) >> 26;
        /** @var int $q */
        $q = ($h9 + $q) >> 25;

        $h0 += self::mul($q, 19, 5);

        /** @var int $carry0 */
        $carry0 = $h0 >> 26;
        $h1 += $carry0;
        $h0 -= $carry0 << 26;
        /** @var int $carry1 */
        $carry1 = $h1 >> 25;
        $h2 += $carry1;
        $h1 -= $carry1 << 25;
        /** @var int $carry2 */
        $carry2 = $h2 >> 26;
        $h3 += $carry2;
        $h2 -= $carry2 << 26;
        /** @var int $carry3 */
        $carry3 = $h3 >> 25;
        $h4 += $carry3;
        $h3 -= $carry3 << 25;
        /** @var int $carry4 */
        $carry4 = $h4 >> 26;
        $h5 += $carry4;
        $h4 -= $carry4 << 26;
        /** @var int $carry5 */
        $carry5 = $h5 >> 25;
        $h6 += $carry5;
        $h5 -= $carry5 << 25;
        /** @var int $carry6 */
        $carry6 = $h6 >> 26;
        $h7 += $carry6;
        $h6 -= $carry6 << 26;
        /** @var int $carry7 */
        $carry7 = $h7 >> 25;
        $h8 += $carry7;
        $h7 -= $carry7 << 25;
        /** @var int $carry8 */
        $carry8 = $h8 >> 26;
        $h9 += $carry8;
        $h8 -= $carry8 << 26;
        /** @var int $carry9 */
        $carry9 = $h9 >> 25;
        $h9 -= $carry9 << 25;

        /**
         * @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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