smithtek-nodered-lora-aes/smithtek-nodered-lora-aes.js

AES security for the PassPort LoRa Module

module.exports = function(RED) {
    // Function to calculate CRC
    function crc(frame) {
        let sum = 0;
        for (let i = 0; i < frame.length; i++) {
            sum += frame[i];
        }
        return sum % 256;
    }

    function SmithTekLoRaAESNode(config) {
        RED.nodes.createNode(this, config);

        const node = this;

        // Handle incoming messages
        node.on('input', function(msg) {
            // Function to process the message
            function processMessage(msg) {
                if (msg.payload === 'enable') {
                    // Fixed enable hex command
                    const enableCommand = Buffer.from([0xAF, 0xAF, 0x00, 0x00, 0xAF, 0x80, 0x40, 0x01, 0x00, 0xCE, 0x0D, 0x0A]);
                    return { payload: enableCommand }; // Send enable command
                } else if (msg.payload === 'disable') {
                    // Fixed disable hex command
                    const disableCommand = Buffer.from([0xAF, 0xAF, 0x00, 0x00, 0xAF, 0x80, 0x40, 0x01, 0x01, 0xCF, 0x0D, 0x0A]);
                    return { payload: disableCommand }; // Send disable command
                } else if (typeof msg.key === 'string') {
                    const magicKey = msg.key.trim();
                    if (magicKey.length === 8) {
                        // Generate magic key hex command
                        const magicKeyCommand = Buffer.from([0xAF, 0xAF, 0x00, 0x00, 0xAF, 0x80, 0x42, 0x08]);
                        const magicKeyAscii = magicKey.split('').map(c => c.charCodeAt(0));
                        const magicKeyCrc = crc([...magicKeyCommand, ...magicKeyAscii]);
                        const magicKeyHexCommand = Buffer.from([...magicKeyCommand, ...magicKeyAscii, magicKeyCrc, 0x0D, 0x0A]);
                        return { payload: magicKeyHexCommand }; // Send magic key command
                    } else if (magicKey.length < 8) {
                        node.error("Error: Key is too short");
                        return null;
                    } else {
                        node.error("Error: Key is too long");
                        return null;
                    }
                } else {
                    // Invalid payload, do nothing
                    return null;
                }
            }

            // Process the input message
            const result = processMessage(msg);

            // Send the result
            if (result) {
                node.send(result);
            }
        });
    }

    RED.nodes.registerType("smithtek-nodered-lora-aes", SmithTekLoRaAESNode);
};