4018

Next logical sequel in our secure crypto-device series, necessary to securely copy and manage sensitive files, before and after encryption/decryption.


So, Alice has just prepared a few gigabytes of good random number OTP sequences using our RNG:

https://www.elektormagazine.com/labs/random-number-generator-150116

They are now stored on the SD. She can give a copy to Bob hand-to-hand, or she can also use the tamper-evident paper-mail box to send it to Bob using any snail-mail service:

https://www.elektormagazine.com/labs/tamper-evident-paper-mail-box-for-secure-distribution-of-one-time-pads

But wait, how is she actually going to make that copy? Using a PC or any general-purpose computer for copying  SD cards with security-crytical info is a "crypto-suicide" by itself. So, this copier device comes in to fill in this security gap! Besides for copying one-time pads, this device will be a complete secure FAT32 file-handling system with the following features:

1.) Direct secure copying from SD1 to SD2. Reaches a speed up to 20Mbit/sec, tested at  32MHz DMA transfer. Entire SD card cloning is also possible.

2.) Comparison and verification of the copied data.

3.) A simple text editor, to securely type simple text messages and store them to SD card before offline encryption with our OTP crypto device:

https://www.elektormagazine.com/labs/one-time-pad-otp-crypto-system

4.) Other basic FAT32 file functions, like delete, rename, format etc.

This can also be used as a secure link between one "dirty" and one "clean" SD card - will copy only the selected data,  sector-wise,  and keep any infections out of the "clean" part of the system, so a "dirty" card, with encrypted data only copied, can then be securely put to a "dirty" PC or smartphone to e-mail the encrypted files.

Hardware is tested in "spaghetti-breadboard" version, software needs to be completed.