Certutil - Base64 encode/decode

Simple utility included comes inbuilt in Microsoft windows : certutil.exe

Link : https://technet.microsoft.com/en-us/library/cc732443(v=ws.11).aspx

Very useful if you want to quickly convert file into base64 encoding format, and probably exfiltrate later ;)

Encoding .PNG file in base64 

Decoding base64 file