ParagonIE_Sodium_Core_Curve25519::fe_frombytes

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Summery Summery

Give: 32-byte string.

Syntax Syntax

ParagonIE_Sodium_Core_Curve25519::fe_frombytes( string $s )

Description Description

Receive: A field element object to use for internal calculations.

Parameters Parameters

$s

(string) (Required)

Return Return

(ParagonIE_Sodium_Core_Curve25519_Fe)

Source Source

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

    public static function fe_frombytes($s)
    {
        if (self::strlen($s) !== 32) {
            throw new RangeException('Expected a 32-byte string.');
        }
        /** @var int $h0 */
        $h0 = self::load_4($s);
        /** @var int $h1 */
        $h1 = self::load_3(self::substr($s, 4, 3)) << 6;
        /** @var int $h2 */
        $h2 = self::load_3(self::substr($s, 7, 3)) << 5;
        /** @var int $h3 */
        $h3 = self::load_3(self::substr($s, 10, 3)) << 3;
        /** @var int $h4 */
        $h4 = self::load_3(self::substr($s, 13, 3)) << 2;
        /** @var int $h5 */
        $h5 = self::load_4(self::substr($s, 16, 4));
        /** @var int $h6 */
        $h6 = self::load_3(self::substr($s, 20, 3)) << 7;
        /** @var int $h7 */
        $h7 = self::load_3(self::substr($s, 23, 3)) << 5;
        /** @var int $h8 */
        $h8 = self::load_3(self::substr($s, 26, 3)) << 4;
        /** @var int $h9 */
        $h9 = (self::load_3(self::substr($s, 29, 3)) & 8388607) << 2;

        /** @var int $carry9 */
        $carry9 = ($h9 + (1 << 24)) >> 25;
        $h0 += self::mul($carry9, 19, 5);
        $h9 -= $carry9 << 25;
        /** @var int $carry1 */
        $carry1 = ($h1 + (1 << 24)) >> 25;
        $h2 += $carry1;
        $h1 -= $carry1 << 25;
        /** @var int $carry3 */
        $carry3 = ($h3 + (1 << 24)) >> 25;
        $h4 += $carry3;
        $h3 -= $carry3 << 25;
        /** @var int $carry5 */
        $carry5 = ($h5 + (1 << 24)) >> 25;
        $h6 += $carry5;
        $h5 -= $carry5 << 25;
        /** @var int $carry7 */
        $carry7 = ($h7 + (1 << 24)) >> 25;
        $h8 += $carry7;
        $h7 -= $carry7 << 25;

        /** @var int $carry0 */
        $carry0 = ($h0 + (1 << 25)) >> 26;
        $h1 += $carry0;
        $h0 -= $carry0 << 26;
        /** @var int $carry2 */
        $carry2 = ($h2 + (1 << 25)) >> 26;
        $h3 += $carry2;
        $h2 -= $carry2 << 26;
        /** @var int $carry4 */
        $carry4 = ($h4 + (1 << 25)) >> 26;
        $h5 += $carry4;
        $h4 -= $carry4 << 26;
        /** @var int $carry6 */
        $carry6 = ($h6 + (1 << 25)) >> 26;
        $h7 += $carry6;
        $h6 -= $carry6 << 26;
        /** @var int $carry8 */
        $carry8 = ($h8 + (1 << 25)) >> 26;
        $h9 += $carry8;
        $h8 -= $carry8 << 26;

        return ParagonIE_Sodium_Core_Curve25519_Fe::fromArray(
            array(
                (int) $h0,
                (int) $h1,
                (int) $h2,
                (int) $h3,
                (int) $h4,
                (int) $h5,
                (int) $h6,
                (int) $h7,
                (int) $h8,
                (int) $h9
            )
        );
    }

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