Encrypt Large amount of User Data(upto 5MB) using Arduino

Projects General Guidance
1

Dear All,
I want to encrypt 5 MB of our data onto External Serial flash using Arduino(DUE) and on request from PC App Arduino(DUE) will transfer the data to PC using UART and on PC end we will decrypt the data. What puzzling me is how can I manage such a large amount of data as many Encryption Algo cannot operate on such large data. And, neither Arduino(DUE) or any Microcontroller have such amount of RAM.

Kindly suggest how to break down my data but still able to encrypt and decrypt 5 MB of it on request from PC.

Preferred encryption is RSA or AES...but suggestion are welcomed.

Thank you

2

Every encryption method that I know of breaks the data down into small blocks and encrypts each block separately.

3

What do you recommend symmetrical or Asymmetrical cipher.

4

Both. Use whatever works best for you.