ParagonIE_Sodium_File::sign_core32

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Private Access Private Access

This function’s access is marked private. This means it is not intended for use by plugin or theme developers, only in other core functions. It is listed here for completeness.

Summery Summery

Sign a file (rather than a string). Uses less memory than ParagonIE_Sodium_Compat::crypto_sign_detached(), but produces the same result. (32-bit)

Syntax Syntax

ParagonIE_Sodium_File::sign_core32( string $filePath, string $secretKey )

Parameters Parameters

$filePath

(string) (Required) Absolute path to a file on the filesystem

$secretKey

(string) (Required) Secret signing key

Return Return

(string) Ed25519 signature

Source Source

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

    private static function sign_core32($filePath, $secretKey)
    {
        /** @var int|bool $size */
        $size = filesize($filePath);
        if (!is_int($size)) {
            throw new SodiumException('Could not obtain the file size');
        }
        /** @var int $size */

        /** @var resource|bool $fp */
        $fp = fopen($filePath, 'rb');
        if (!is_resource($fp)) {
            throw new SodiumException('Could not open input file for reading');
        }
        /** @var resource $fp */

        /** @var string $az */
        $az = hash('sha512', self::substr($secretKey, 0, 32), true);

        $az[0] = self::intToChr(self::chrToInt($az[0]) & 248);
        $az[31] = self::intToChr((self::chrToInt($az[31]) & 63) | 64);

        $hs = hash_init('sha512');
        hash_update($hs, self::substr($az, 32, 32));
        /** @var resource $hs */
        $hs = self::updateHashWithFile($hs, $fp, $size);

        /** @var string $nonceHash */
        $nonceHash = hash_final($hs, true);

        /** @var string $pk */
        $pk = self::substr($secretKey, 32, 32);

        /** @var string $nonce */
        $nonce = ParagonIE_Sodium_Core32_Ed25519::sc_reduce($nonceHash) . self::substr($nonceHash, 32);

        /** @var string $sig */
        $sig = ParagonIE_Sodium_Core32_Ed25519::ge_p3_tobytes(
            ParagonIE_Sodium_Core32_Ed25519::ge_scalarmult_base($nonce)
        );

        $hs = hash_init('sha512');
        hash_update($hs, self::substr($sig, 0, 32));
        hash_update($hs, self::substr($pk, 0, 32));
        /** @var resource $hs */
        $hs = self::updateHashWithFile($hs, $fp, $size);

        /** @var string $hramHash */
        $hramHash = hash_final($hs, true);

        /** @var string $hram */
        $hram = ParagonIE_Sodium_Core32_Ed25519::sc_reduce($hramHash);

        /** @var string $sigAfter */
        $sigAfter = ParagonIE_Sodium_Core32_Ed25519::sc_muladd($hram, $az, $nonce);

        /** @var string $sig */
        $sig = self::substr($sig, 0, 32) . self::substr($sigAfter, 0, 32);

        try {
            ParagonIE_Sodium_Compat::memzero($az);
        } catch (SodiumException $ex) {
            $az = null;
        }
        fclose($fp);
        return $sig;
    }

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