The development of software/hardware system for safe data transfer and protected USB dongle for online banking

Protected USB dongle with integrated browser for online banking

Project Overview

Under the order of a Swiss provider of Internet solutions for the banking industry, we have developed a software/hardware system for safe data transfer while working on an insecure computer terminal. The device is based on a USB flash drive with a shock-proof enclosure and additional features.

Key features of USB dongle for online banking

The USB dongle features specially designed software for launching applications (launcher), as well as a library with PKCS (public key cryptographic standard) #11
Authorization in the system involves PIN code protection, digital signature and encryption / decryption of downloaded data
Online blocking of client software is available
Protected user data storage: information is permanently deleted
A user interface for working with a bank account is provided by integrated Mozilla Firefox with additional settings for enhanced security:
- Full automatic data verification to prevent unauthorized replacement
- The device is set to work with a specific bank, so the replacement of a web page causes a security error
- User identification data are hidden and unreadable

Technical parameters

Model	SanDisk Extreme Cruzer Contour
Smart technology support	U3
Enclosure	Liquidmetal®
Pressure resistance	900 kg
Memory	4 to 64 GB
Write/read speed	write speed: up to 18 MB/sec read speed: up to 25 MB/sec
Password protection	+
AES encryption	+
USB port	USB 2.0

Project summary

In the process of developing a secure USB dongle with an integrated browser, Promwad experts performed the following tasks:

— Selection of the optimal hardware platform
— Software development
— Prototyping

How It's Made

Customer

Swiss company specializing in Internet solutions for e-commerce and client-bank systems.

Objective

To develop a hardware and software solution for secure transaction between a bank and its clients when unsecure computer terminal is used. The product must provide the following functionality:

Tamper (Secure) storage of user identification information
User identification information should have restricted knowledge based algorithm. Identification information shouldn’t have a sense without user know component (like PIN)
User-know component should have possibility to change without any reencrypting user files
Secured execution client software at unsecured PC
Integrity checking of client software to detect attacker modification
Guaranteed secure update, checking for substitution by fishing site
Online possibility booking client software
Encrypting / decrypting user private files
Encrypting / decrypting downloading data
Sign/check sign of user data
Secure delete operation
Client software should work under Microsoft(c) Windows XP(c), Microsoft(c) Windows Vista(c)

Solution

As the hardware platform was selected USB smart drive by SanDisk supporting U3 technology. SanDisk Extreme Contour is an extremely rugged and smart USB flash drive. It is built with Liquidmetal® casing that is crash-resistant to over 2,000 lbs. SanDisk Extreme Contour also includes U3 smart technology which deals with security functions

1. Hardware

A U3 flash drive presents itself to the host system as a USB hub with a CD drive and standard USB mass storage device.

This configuration causes Windows disk management to show two drives:

A read-only ISO9960 volume on an emulated CD-ROM drive with an autorun configuration to execute the U3 LaunchPad
A standard flash drive (FAT formatted) that includes a hidden "SYSTEM" folder with installed applications

Table 1. SanDisk Extreme Contour flash drive specification

Capacities	4GB, 8GB, 16GB, 32GB and 64GB
Read and write performance	Up to 25MB/sec read and 18MB/sec write
Password protection	Supported in Windows(c) XP and Windows(c) Vista
AES encryption	Supported in Windows(c) XP and Windows(c) Vista
USB port	Hi-Speed USB 2.0

2. Software

Software consists from four independent parts:

Launcher software, to provide all security operation and controlling algorithms
Mozilla Firefox customized browser to provide user web interface for interaction with banks account
Secure token library, connected to Mozilla Firefox browser and provided PKCS#11 functionality

Launcher software developed for:

Quick access to functionality
Providing software AES 256 encryption of client files
Integrity checking of internal components and Mozilla Firefox components
Getting secure update from customer
Online activation software by booking number

All user private identification information and data are stored in encryption partition. Launcher software used u3dapi library interface to get SanDisk U3 AES 256 encryption algorithm and tamper storage.

Launcher user interface have a progress bar with display of integrity checks current state. If malware try to made changes, user notification is present immediate and session would be security destroyed.

The secure delete algorithm makes impossible to recover deleted data from stick.

Mozilla Firefox browser customized for increase security:

Launching from portable device – no temporary files stored on local HDD
Excluded build-in object token – no possibility to add or change objects by malware
Developed Mozilla Firefox download extension – prevent creating plaintext temporary file
Minimized plugins and extension loading – no possibility to attach malware module

Secure token library attached to Mozilla Firefox browser as PKCS#11 library and provide:

Getting certificate object from client software – no possibilities to add or substitute certificate authority
Performs AES encryption
Performs RSA encrypting and key distribution
Provides external random generator to OpenSSL

Firefox browser has ability to download files to encrypted temporary storage thus preventing fishing of Firefox downloadable extensions

Advantages

Portable browser solution has an integrity checking to prevent fake substitution of malicious components
Portable browser customized for bank interaction, substitution of bank page cause a security error
Protected file storage for user data files
Hidden and unreadable user identification data
Secure delete algorithm to prevent recovery user deleted files

Programming languages	C++, JS
Interfaces	USB 2.0
Development tools	MSVC2005, MinGW
Project management tools	dotProject, SVN
Project duration	5 months