Flash drives are becoming more and more popular in today’s digital lifestyle, as they are a convenient way to transport important data. These tiny devices are so small, that they can become easily lost or stolen, so how do you secure your personal information? Some of these devices incorporate password features in the drive’s firmware, and you can add encryption to any device, but a determined hacker can circumvent this software protection.
More and more portable media vendors are moving towards making their devices more secure, as the Sarbanes-Oxley Act, HIPAA, and other initiatives now make digital trespassing a prosecutable crime. Manufacturing costs for these devices are also dropping, so adding more security to a drive doesn’t impact the manufacuring cost that much.
As previously mentioned, some USB drives use various methods to secure the precious data on the memory stick, but these software methods only logically lock the drive or encrypt its contents. One of the problems with a software method is that the protection can be circumvented by using another OS or running a password-checking program.
Corsair has delivered an answer to this problem with their Padlock line of USB flash drives. These drives use a physical numeric keypad, combined with a hardware mechanism to lock or unlock the drive before use. Once locked, no computer will be able to use it, regardless of the platform. The hardware protects the drive at its lowest level, so not even a drive letter is mapped.
The Flash Padlock contains a flash memory controller and flash memory IC (as all USB flash drives do). However, the Padlock is also equipped with a six-button keyboard and seperate security processor.
The security processor enables or disables operation of the Flash Padlock drive. When the drive is disabled, it will be completely invisible to the system that it is plugged into (much like a printer that is not powered up). When the combination is successfully entered, the drive is activated, and operates as a normal USB flash drive. This operation continues until the drive is unplugged from the system.
The combination itself is programmable and can be entered regardless of whether the drive is plugged into the computer. If the onboard battery ever fails, you can still enter the combination once the drive is plugged into a powered USB port.
Flash wear leveling is a technique used to help prolong the life of USB Flash drives.
Data can be written to an address on a flash memory IC a finite number of times. Even though the allowable number of writes is large (typically 10,000 or 100,000), if you write to the same spot over and over and over, it is conceivable that the flash device would wear out at that location. So, flash drives use wear leveling to make sure this does not happen.
How does wear leveling work?
Wear leveling works to distribute data evenly across each memory block of the entire USB Flash drive. This process decreases the total wear on the drive, thereby increasing the lifetime of the drive.
In order to understand how wear leveling works, one needs to understand the basics of how memory is stored and addressed on a flash drive. A couple terms to be familiar with are LBA and PBA.
LBA (Logical Block Address): The LBA is the address that the operating system uses to read or write a block of data on the flash drive.
PBA (Physical Block Address): The PBA is the fixed, physical address of a block of data on the flash drive.
The USB Flash Drive Controller resides on the flash drive, and provides the lookup table to map which PBA contains the data assigned to a given LBA. Since a lookup table is used, the data for a given LBA can be stored at nearly any PBA on the drive.
How does the “leveling” happen?
As we have discussed, the controller uses a lookup table to map the LBA to the PBA; it is a lot like the index of a book. So, the data can physically be moved, and all one has to do is change the index, and the data can still be found with ease.
Since one can move the data around with little or no penalty, the controller constantly does just that. Updated or new data is written to the first available free block with the least number of writes. The block that contains old data is erased in the background and then marked as a free block. This block rotating technique ensures even wear of memory blocks across the USB Flash drive. The wear leveling process is transparent to the Operating System.
The following is a very simplified example, illustrated in figure 2. At the start, we have PBA #1 through #4 containing data, and PBA #5 and #6 are “free”, or empty. When the computer writes new data to LBA15, the controller writes the new data to PBA #5, instead of PBA #1, where LBA15 used to reside. PBA #1 is now “free”. Now, we will write to LBA14. As with LBA15, the data is written to a new PBA, and PBA #3 is now free. Finally, we will write to LBA14 a second time. Once again, the LBA is moved to a new physical address. Using a far more complex version of this activity, the writes to the flash drive are made fairly constant across the device.
What is static wear leveling?
This technique wear-levels over both dynamic and static data areas (see figure 3). For example, an 8GB Flash Voyager stores 3GB of MP3 music files. The entire 8GB capacity can be used for wear leveling.
Reassigning static data is a more complex task than dynamic data because it requires multiple operations to safely move static data around. As a result, this implementation may impact the overall write performance.
What is dynamic wear leveling?
This technique only wear-levels over dynamic data areas (see figure 3). For example, an 8GB Flash Voyager stores 3GB of MP3 music files but only 5GB remaining capacity is free for wear leveling.
The dynamic data areas are rotated in the round-robin fashion from a pool of free blocks. Dynamic wear leveling has a shorter life expectancy compared to static wear leveling because only dynamic data areas can be used to rotate data.
Static Wear Leveling vs. Dynamic Wear Leveling : Tradeoffs
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Which kind of wear leveling do Corsair drives use?
Corsair’s flash drives typically use dynamic wear-leveling. The reason for this is that dynamic wear-leveling is less complicated to implement, and provides endurance that is more than adequate for consumer flash drive applications.
Included in the package is a lanyard, USB extension cable, a quick-start guide and the USB drive itself. The device includes a 3 volt lithium batter and 1 or 2GB of onboard flash memory (priced at $29.99 and $39.99 respectively).
Features:
- Auto-Locking – Self locking after removal from computer
- Customizable PIN – Set your own PIN and make it easy to remember
- Easy to Use – Direct keypad access and indicator lights make locking/unlocking simple
- Plug and Play – Hardware based security works without installing or running software
- Platform independent – Works on Windows, MAC and Linux platforms without the use of software
The black drive is a little larger than other similar USB drives and blocky. The bulk may be a turnoff for some people, as many drives try to look sleek and sexy and fit nicely on your keychain on in your pocket. On the flip side, this unit will be a little harder to misplace.
The top of the drive has a series of six buttons. The first button has a key icon, which is used to begin and end the password sequence. The other five buttons are numbered 0-1, 2-3, 4-5, 6-7, and 8-9 (each button has two numbers). There are also two small padlock icons with small LEDs under them, one indicating locked and the other unlocked. The locked icon flashes red when the drive is in a locked state, and the unlock icon flashes green for a short time when the device has been unlocked (i.e. you enter the correct password). Once the drive is removed, it will automatically lock itself within fifteen seconds (unless it is plugged into another computer within the time window). This feature is great in that the user does not have to remember to lock the drive; it also prevents a user from accessing the drive if they steal it from your desk while you’re at lunch.
Since there is a hardware layer, if you ever forget the pin, then there’s no way to retrieve it without destroying the drive. Corsair lets you register your PIN on its website, so it can easily be retrieved should it be forgotten.
Corsair Flash Padlock 2GB Performance Test
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Corsair’s padlock drive performs better than other comparable USB drives, and even managed to get close to the read speed of the laptop’s internal 60GB hard drive. Given this read speed, you will certainly be able to run portable applications very quickly, as well as stream media from the drive without any hicups. Corsair also employs dynamic wear-leveling technology to extend the life of the drive. According to Corsair, the drive will handle at least 10,000 write cycles, which should last the average user for well over ten years.
The performance of the Corsair Padlock flash drive really surprised me. I haven’t seen a flash drive that could reach 18MB a second. At this speed, you could easily use a portable version of Firefox without any slowdown.
The unit isn’t as attractive as other USB flash drives, and is a little bulkier, too. Although there are holes to attach a lanyard, none is included. There is also no attach the cap to the base, so the cap can be eaily lost.
The padlock is an interesting idea, and is a secure way to protect your data from prying eyes if it is ever lost or stolen. You can set a fairly lengthy combination to protect your data, and there is a good window of time to connect the drive after it’s been unlocked. There are no frills as far as U3 or Ceedo support, but there are a ton of portable apps that don’t require this specification.
2GB flash drives are now very affordable, and can be found online between $20 and $40. At an average retail price of $35, the Corsair Padlock is on the high end of 2GB flash drives. Even if you don’t use the security feature of the drive, this is easily one of the fastest available, making the use of portable applications alot less painful.
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