ParagonIE_Sodium_Compat::crypto_kx( string $my_secret, string $their_public, string $client_public, string $server_public, bool $dontFallback = false ): string

2017    public static function crypto_kx(2018        #[\SensitiveParameter]2019        $my_secret,2020        $their_public,2021        $client_public,2022        $server_public,2023        $dontFallback = false2024    ) {2025        /* Type checks: */2026        ParagonIE_Sodium_Core_Util::declareScalarType($my_secret, 'string', 1);2027        ParagonIE_Sodium_Core_Util::declareScalarType($their_public, 'string', 2);2028        ParagonIE_Sodium_Core_Util::declareScalarType($client_public, 'string', 3);2029        ParagonIE_Sodium_Core_Util::declareScalarType($server_public, 'string', 4);2030 2031        /* Input validation: */2032        if (ParagonIE_Sodium_Core_Util::strlen($my_secret) !== self::CRYPTO_BOX_SECRETKEYBYTES) {2033            throw new SodiumException('Argument 1 must be CRYPTO_BOX_SECRETKEYBYTES long.');2034        }2035        if (ParagonIE_Sodium_Core_Util::strlen($their_public) !== self::CRYPTO_BOX_PUBLICKEYBYTES) {2036            throw new SodiumException('Argument 2 must be CRYPTO_BOX_PUBLICKEYBYTES long.');2037        }2038        if (ParagonIE_Sodium_Core_Util::strlen($client_public) !== self::CRYPTO_BOX_PUBLICKEYBYTES) {2039            throw new SodiumException('Argument 3 must be CRYPTO_BOX_PUBLICKEYBYTES long.');2040        }2041        if (ParagonIE_Sodium_Core_Util::strlen($server_public) !== self::CRYPTO_BOX_PUBLICKEYBYTES) {2042            throw new SodiumException('Argument 4 must be CRYPTO_BOX_PUBLICKEYBYTES long.');2043        }2044 2045        if (self::useNewSodiumAPI() && !$dontFallback) {2046            if (is_callable('sodium_crypto_kx')) {2047                return (string) sodium_crypto_kx(2048                    $my_secret,2049                    $their_public,2050                    $client_public,2051                    $server_public2052                );2053            }2054        }2055        if (self::use_fallback('crypto_kx')) {2056            return (string) call_user_func(2057                '\\Sodium\\crypto_kx',2058                $my_secret,2059                $their_public,2060                $client_public,2061                $server_public2062            );2063        }2064        if (PHP_INT_SIZE === 4) {2065            return ParagonIE_Sodium_Crypto32::keyExchange(2066                $my_secret,2067                $their_public,2068                $client_public,2069                $server_public2070            );2071        }2072        return ParagonIE_Sodium_Crypto::keyExchange(2073            $my_secret,2074            $their_public,2075            $client_public,2076            $server_public2077        );2078    }