How to simulate a thumb driver in local

In a project we needed to simulate a thumb driver for multi user system ,
share public keys over network.


A thumb driver does not share it's private key.
We can simulate a thumb driver in our local.


Project will enable users of system to use their local laptops or
usb drives as thumb drive.

So let's write basic principles for this simulation.
1)All encryption decryption must occur at local machine.

2)All data send over network must be encrypted

3)User public keys must be kept at server.(Public key distribution server better to
be on a different server than data server)

4)RSA is slow for file encryption.Encrypt Files with AES.
Encrypt AES keys with every user's public key put to server.
***You have one door,one key.
for n users clone key and put in a box only that target user have key(user's private key)