Just posting this for documentation purposes. I am working on porting the pygogogo2 driver from python and hass.io to hubitat / groovy. I am almost there and wanted to post some of the harder bits here.
They were just hard for me as I didn't know any Groovy before this. I borrowed heavily from the GoGo2 driver created by @mgroeninger He helped get me down the road a bunch.
So here is the hot steamy mess of AES encryption and decryption:
import javax.crypto.spec.SecretKeySpec;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.Cipher
/ do the magic
def encrypt (def plainText, def secret) {
log ("Encrypting - ${plainText}","trace")
// this particular magic sauce pads the payload to 128 bits per chunk
// even though that shouldn't work with S5Padding....
def cipher = Cipher.getInstance("AES/CBC/PKCS5Padding", "SunJCE")
SecretKeySpec key = new SecretKeySpec(secret.getBytes("UTF-8"), "AES")
// generate an Initial Vector using Random Number and no additional libraries....
// because they don't exist here....these are not the SecureRandom numbers you are looking for.....
def IVKey = Long.toUnsignedString(new Random().nextLong(), 16).toUpperCase()
IvParameterSpec iv = new IvParameterSpec(IVKey.getBytes("UTF-8"))
// initialize the encryption and get ready for that dirty dirty magic
cipher.init(Cipher.ENCRYPT_MODE, key, iv)
// boom goes the dynamite
def result = cipher.doFinal(plainText.getBytes("UTF-8")).encodeBase64().toString()
// extract the Initial Vector and make it a string so we can pre-pend to the GoGoGate2
// encryption string. Someone way smarter than me did it so I am doing it too...
// looking at you broadfoot..
def ivString = cipher.getIV()
ivString = new String(ivString, "UTF-8")
// prepend the IV to the Result and send it back....still needs to be URLEncoded etc......
// but we now have a valid payload. Serioulsy...this was hard.....Python is WAY easier
// when it comes to some of this manipulation....but at least I didn't have to use a lambda.
return ivString+result
}
// undo the magic
def decrypt (def cypherText, def secret) {
log ("Decrypting - ${cypherText}","trace")
// this was so much easier to get done than the encryption. It works. Don't touch it
// cereal. you will regret it.
// rip off the iv bandaid.....
def iv = cypherText.take(16)
log ("IV: ${iv}","trace")
// drop those beats..or bytes.
byte[] decodedBytes = cypherText.drop(16).decodeBase64()
log("decodedBytes: ${decodedBytes}", "trace")
// no whammy no whammy no whammy.......
def cipher = Cipher.getInstance("AES/CBC/PKCS5Padding", "SunJCE")
SecretKeySpec key = new SecretKeySpec(secret.getBytes("UTF-8"), "AES")
cipher.init(Cipher.DECRYPT_MODE, key, new IvParameterSpec(iv.getBytes("UTF-8")))
//whammy!
return new String(cipher.doFinal(decodedBytes), "UTF-8")
}
