PHP LoRa

PHP-implementation of a LoRa-payload decryption

LoraMac decrypt, which is actually encrypting each 16-byte block and XORing that with each block of data.

This method is based on loramac_decrypt() written in Python here https://github.com/jieter/python-lora/blob/master/lora/crypto.py

...which in turn is based on LoRaMacPayloadEncrypt() by Semtech in https://github.com/Lora-net/LoRaMac-node/blob/master/src/mac/LoRaMacCrypto.c#L108