Nodejs crypto good practice AES-CBC + SHA256 + HMAC

gistfile1.js

// var cryptoKey = raw SHA256 Hash

function decypherPayload(payload) {
	
	/* inputs */
	var t = payload.split(",");
	var C = t[0], 
		IV = t[1], 
		Hm = t[2];
	
	/* compute hmac */
	var c = crypto.createHmac("sha256", cryptoKey);
	c.update(C, "ascii");
	c.update(IV, "ascii");
	c.update(cryptoKey, 'binary');
	var hmac = c.digest("hex");
	
	/* integrity control */
	if(hmac != Hm)
		return({ error: true, message: "Bad HMAC control" });

	try {
		var dcp = crypto.createDecipheriv("aes-256-cbc", cryptoKey, new Buffer(IV, "hex"));
		var pl = dcp.update(payload, 'hex');
		pl += dcp.final("ascii");
	} catch(e) {
		return({ error: true, message: "Decipher: "+e.message });
	}

	try {
		js = JSON.parse(pl);
	} catch(e) {
		return({ error: true, message: "JSON error: "+e.message });
	}
	
	return({ error: false, data: js });
}

function cypherPayload(data) {
	var iv = crypto.randomBytes(16);
	
	var c = crypto.createCipheriv("aes-256-cbc", cryptoKey, iv);
	data.ip = ip;
	var pl = c.update(JSON.stringify(data), 'utf8', "hex");
	pl += c.final("hex");
	iv = iv.toString("hex");
	
	c = crypto.createHmac("sha256", cryptoKey);
	c.update(pl, "ascii");
	c.update(iv, "ascii");
	c.update(cryptoKey, 'binary');
	var hmac = c.digest("hex");

	return(pl+","+iv+","+hmac);
}