Dear Arduino-Community,
(Sorry for my poor english in advance 
)
I'm a total newbie with arduino and this question is not meant to get specific guidance for my build. I'm just asking if my project is realisable at all.
I'm planning a password-manager where i can store several passwords and other sensible data. My goal is, to make a little box, which i can connect to any PC.
The box should then get recognized as a e.g. keyboard in some way, it should only read data which i give out specificly from Arduino. So there should be no direct way, from the PC to read my stored data, it must only be given from the box after i press e.g a button on the box.
The important thing to me is, is this "oneway-connection" realisable?
Before i dig deeper into arduino, at least for this project, i wanted to make sure there is no deadend.
Thank you in advance for your responses,
Greetings from Germany
Herb
With an Arduino that can act like a HID (e.g. Leonardo, there are others), that sounds very feasible.
Hello. I'm working on similar project and have some issues as well.
At the moment my code looks like a compilation of many pieces of examples bu already got into troubles.
So, idea was little device with oLED display, Leonardo board and SD card. Basically you can browse and enter logins and passwords.
First issue was to little EEPROM so I decided to use SD card. And here comes the main problem, it can't read the card due to lack of RAM, after initializing display and memory card there is no room for anything else.
Most likely I do something wrong. I used other projects as references but they all read and print files directly into display. While write it into String for future processing.
t this point I just want to know if it's even possible for Arduino to handle such functionality.
Both libraries are using lots of memory. So a Leonardo might not cut it. There seems to be a library for the oled that doesn't use as much (not sure about it exactly).
Alternative to SD might be an external eeprom or fram module.
And possibly a newer board with more memory might do the trick. Can't really advise as I don't know specs from the head; an Arduino Due would be one as far as I know.