Archive for the ‘electronics’ Category
When in 2000 Philips Research first announced their development of e-paper I was very excited I went as far as to investigate what would be needed to attach a microcomputer which could attach to the e-paper and create a real electronic NewsPaper. I got a microcomputer manufacturer, who gave me an option of including bluetooth so data could be transferred via a mobile device and was willing to integrate the e-paper. The specification that Philips had announced for the e-paper were not completely clear regarding the integration of the device, and we didn’t consider this to be too big an issue. And a friend had already been working on a mobile payment system, which I wanted to use. I even had a large content provider willing to fund a possible a PoC.
The specifications for the device contained:
- Mobile ARM processor
- some MBs storage
- some MBs memory
- BlueTooth using PDA Sync or Serial Port (COM1) with Data Transfer
The microcomputer was able to run a 2.4 linux kernel, with all of the hardware supported by the kernel. The only thing I would be required to do is write a driver for the e-paper, which I didn’t consider rocket science. The only real issue might have been battery-life, although the specification for the e-paper had extremely low power requirements.
Innocent as I was I thought that Philips Research would be overjoyed to have somebody ask them to produce a prototype with no cost to them. They didn’t even reply to my repeated mails.
In continuation of my article: Data Erasing for your own Protection I got into a discussion about other ways to protect you data from law enforcement.
I was told by a former law enforcement member that after the crime scene has been secured that the the computer tech checks the computer is functional and then has the equivalent of a mover ship the computer, like a box, to the computer lab. The issue with this being that a mercury switch and power source could be used to zap the computer with the needed Gauss to erase/destroy the hard disk.
Another method would be to use a RAM Disk, whether this is a physical or virtual RAM Disk. The first has the advantage that in the case of a brownout the data is saved for X hours, although this could be a disadvantage too, another disadvantage is that you may have a memory limit which is imposed by the hardware. The advantage over the physical RAM disk is that a higher amount of memory can be allocated, although you don’t get the protection from brownouts.
Important to also remember is that there is also a data remanence with data in RAM, which also should to be mitigated. This may be possible by passing an electric charge over the memory to erase them, although I have yet to find relevant references.
A third method may be by raising the temperature of the hard disk to above the Curie Point, which with effect the magnetics of the disk. I will need to investigate this more too.
Embedding part of the computer in epoxy still applies to all the above.
- Gigabyte I-RAM DDR PCI Virtual RAM Disk Drive SATA W/ Backup Battery – backup power lasts ~16 hours and it supports 4Gb RAM.
- Data remanence: Data in RAM
- Curie Point
Image source: Michiel2005
I’ll describe the problem I think that you have: You have data stored on computers which you don’t want the police or the governments to have, something that cryptography can not protect, as XKCD so eloquently puts in the cartoon Security below. You are not the only one: internet companies; financial institutions; churches; organizations working for freedom; lawyers; criminals and innocent individuals all need to protect themselves.
It’s possible to use something like Darik’s Boot and Nuke (DBAN) which is a self-contained boot disk that securely wipes the hard disks of most computers, however this takes time sometimes a number of hours and requires human interaction. Time that may not be available if the long arm of the law comes down on you like a ton of bricks. And it can even be the case that the power is shut off before the computer is secured, the police do this to keep the data on the computer secured for the investigation. So I thought about what would be needed to magnetically erase the hard disk.
Secondly I read that degaussing can cause permanent irreversible damage to hard drives which means they are not reusable. Unlike tapes the mechanism to read the magnetic track is part of the device and is also magnetic. So don’t expect to be able to use the disk after you have tested the electromagnet.
Thirdly the magnetic induction (also referred to as magnetic flux density or saturation flux density) needed to correctly erase some hard disk can be from 6000 – 7000 gauss (0.6 – 0.7 tesla), an NSA approved degausser puts out 22000 gauss (2.2 telsa). From some sources I learned that mostly the core of electromagnets is made from a magnetic material – power ferrite – which has a magnetic flux density of under 4000 gauss, this wouldn’t be enough. A different material would be needed for the core of the electromagnet. I discovered that MPP (molypermalloy powder) material has a magnetic flux density of 7000 gauss, which is what is needed for this PoC. Iron powder and high-flux can yield 10000 and 15000 gauss respectively.
Fourth you need thick copper wire wound round the core, this is called a solenoid. This creates the B-field which is the magnetic field which will erase the hard disk, using a gauss or EMF meter it is possible to measure the magnetic flux density in gauss or telsa produced by your electromagnet and experiment with getting the level to 6000-7000 gauss.
Fifthly you need an Uninterruptible Power Supply (UPS), this will ensure that when the power is switched off that the electromagnet is powered up to erase the hard disk.
Lastly you need to install your electromagnet round your hard disk, hook up the UPS and fill the computer with epoxy so it cannot be taken apart by the police. Let’s just hope you don’t have a brownout. 😉
Sadly this method will not work for solid state disks, although you can possibly attach squibs using a similar setup. That may be something for a future article.
- Degaussing : Irreversible damage to some media types
- I am creating an electromagnet for my school’s science fair project. Does the shape of the iron core make a difference? […]
Image source: Michiel2005
I’d seen on Ars Technica that Microsoft had released Windows Live Messenger for the CrackBerry. I had already had GTalk, which didn’t work on my Curve, and Yahoo! Messenger, which I could already use to chat with my my MSN contacts.
I found some other CB applications:
I was looking for CrackBerry tools and discovered that the BlackBerry’s Crypto kernel is FIPS compliant. It is obvious otherwise it couldn’t be used by certain elements of the world governments who consider FIPS compliance to be obligitory.
BlackBerry® Cryptographic Kernel Validated to FIPS 140-2
Ok, so not really with a Fiat 500, with a avalanche photodiode. An photodiode converts light (photons) into either current or voltage. You’ve probably seen it in use if you have a light which switches on when it gets darker.
An avalanche photodiode is more sensitive compared to other semiconductor photodiodes, but are still not able to distinguish between one photon or multiple photons arriving. Andrew Shields explains how to use a standard avalanche photodiode so that it counts photons as they arrive in the article An avalanche-photodiode-based photon-number-resolving detector. “ That’s like turning a Fiat 500 into a Ferrari.”
It’s actually relatively simple, when you think about it. A photon causes a certain amount of energy to be released when it first hits the avalanche photodiode, two photons cause twice the amount of to be released. At this early stage, say Shields and friends, the avalanche current is proportional to the number photons that have struck.
The reason this is so impressive is that it reduces the cost of detecting photons down. Currently the last mile for ISPs is almost exclusively over copper, this discovery makes it cheaper to put glass fibre in your home. And as mentioned in the abstract it makes optical quantum computing more of a reality.