The STM32F103(Bluepill) has been used to achieve this project. It can either be programmed using JTAG or can be done using UART. The pinout of the cheap JTAG connector can be seen here and the pinout ...
Add base64.cpp and base64.hpp to your project folder or library search path, put #include "base64.hpp" in your source, and pass base64.cpp to your compiler ...