PORTS Forum

Ports and Interfaces => USB => Topic started by: ianlokejj on February 18, 2014, 10:52:36 pm

Title: USB encryption/decryption project
Post by: ianlokejj on February 18, 2014, 10:52:36 pm

Hi,

I'm starting on a project which involves developing a USB device which can simultaneously be 1. seen as a MSD to a host (PC) 2. seen as a host to USB flash drives.

What I am trying to achieve is something like the Addonics USBcipher (http://www.addonics.com/products/cipherusb.php). The device will encrypt and decrypt data written and read into a connect USB flash drive.

I was considering using a PIC18F4550 which is configured as a mass storage device. However it does not seem to be able to be interfaced with a USB flash drive to read and write data.

Does anyone have a recommendation on how to go about doing this?

Thanks

Title: Re: USB encryption/decryption project
Post by: Jan Axelson on February 19, 2014, 09:22:07 am

With mass-storage firmware, the PIC18F4550 functions as a flash drive itself; it doesn't interface to one. Microchip also has USB host chips.

I don't know how the USBcipher works but possibly it contains a mass-storage device (the plug interface) that attaches to a PC along with an embedded host (the receptacle) that encrypts/decrypts the mass-storage data and writes the data to/reads the data from an attached drive. The firmware would need to manage the two hosts (embedded and PC) that are accessing the embedded mass-storage device so only one host accesses the device at a time. One way to find out would be to obtain one and hook it up to a protocol analyzer.

BitLocker and other software can also encrypt flash drives.

Title: Re: USB encryption/decryption project
Post by: ianlokejj on February 19, 2014, 10:53:50 am

Thank you for the feedback Jan.

I have proceeded to order a USBCipher. I do hope to provide updates when I start analyzing it's protocol.