Хорошая либа для отправки логов на серверhttps://github.com/arcao/Syslog
https://github.com/alejho/Arduino-Telnet-Client A minimal (but real) telnet client for Arduino, actually able to login and send commands to a generic telnet server.
https://github.com/DavyLandman/AESLib At the moment only 128bit keys are supported, the blocksize is also fixed at 128bit. This means that the key array and possible iv array should contain exactly 16 bytes (uint8_t or byte). Moreover the amount of bytes to encrypt should be mod 16. (this means you have to take care of padding yourself).