This is a form of the libosdp code, edited for the Arduino. Having said that, this code is likely too large for a ATMEGA328P. I have been working on a STM32F030R8, in the form of a Nucleo64 Board. I hooked up the MAX232 to D2/D3/D8, which allowed debugging on the other serial port. The LibOSDP library copies parts of the following codebases: * https://github.com/goToMain/libosdp * https://github.com/goToMain/c-utils/ It also uses the TinyAES library from libosdp. There are numerous changes to make this fit into the Arduino structure, including leveling out the directory structure and including files from c-utils into this code base. Eventually I might physically fork things at a later date, but may not. I need to do more work for replacing numerous #defines. I have not even looked at osdp_cp.c. Numerous changes are likely needed There are two parts to this: * Arduino .INO program * Arduino LibOSDP Library These live in the following respositories respectively: * https://github.com/vk2tds/libosdp_pd * https://github.com/vk2tds/libosdp_arduino