ParagonIE_Sodium_Compat::crypto_scalarmult( string $secretKey, string $publicKey ): string

2553    public static function crypto_scalarmult(2554        #[\SensitiveParameter]2555        $secretKey,2556        $publicKey2557    ) {2558        /* Type checks: */2559        ParagonIE_Sodium_Core_Util::declareScalarType($secretKey, 'string', 1);2560        ParagonIE_Sodium_Core_Util::declareScalarType($publicKey, 'string', 2);2561 2562        /* Input validation: */2563        if (ParagonIE_Sodium_Core_Util::strlen($secretKey) !== self::CRYPTO_BOX_SECRETKEYBYTES) {2564            throw new SodiumException('Argument 1 must be CRYPTO_BOX_SECRETKEYBYTES long.');2565        }2566        if (ParagonIE_Sodium_Core_Util::strlen($publicKey) !== self::CRYPTO_BOX_PUBLICKEYBYTES) {2567            throw new SodiumException('Argument 2 must be CRYPTO_BOX_PUBLICKEYBYTES long.');2568        }2569 2570        if (self::useNewSodiumAPI()) {2571            return sodium_crypto_scalarmult($secretKey, $publicKey);2572        }2573        if (self::use_fallback('crypto_scalarmult')) {2574            return (string) call_user_func('\\Sodium\\crypto_scalarmult', $secretKey, $publicKey);2575        }2576 2577        /* Output validation: Forbid all-zero keys */2578        if (ParagonIE_Sodium_Core_Util::hashEquals($secretKey, str_repeat("\0", self::CRYPTO_BOX_SECRETKEYBYTES))) {2579            throw new SodiumException('Zero secret key is not allowed');2580        }2581        if (ParagonIE_Sodium_Core_Util::hashEquals($publicKey, str_repeat("\0", self::CRYPTO_BOX_PUBLICKEYBYTES))) {2582            throw new SodiumException('Zero public key is not allowed');2583        }2584        if (PHP_INT_SIZE === 4) {2585            return ParagonIE_Sodium_Crypto32::scalarmult($secretKey, $publicKey);2586        }2587        return ParagonIE_Sodium_Crypto::scalarmult($secretKey, $publicKey);2588    }