Solid material comminution or disintegration – Processes – Miscellaneous
Reexamination Certificate
2001-09-18
2003-07-08
Rosenbaum, Mark (Department: 3725)
Solid material comminution or disintegration
Processes
Miscellaneous
C241S101400, C241S260100
Reexamination Certificate
active
06588687
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to high-security removal of data from information bearing disks, especially high-security removal of data from ordinary CDs, CDRs, CDRWs and DVDs.
BACKGROUND OF THE INVENTION
Compact disks (CDs) include three types: ordinary CDs, CDRs and CDRWS. These disks store data in little pits burned into the disk, or optically in a very thin light-sensitive dye layer on the disk. The information is stored in a very thin layer under the label. That stored information theoretically can be scraped off into small enough pieces so that the data cannot be read. That is, the data can be mechanically disintegrated. CDRs are also known as WORMs, i.e., Write Once Read Many. Relatively speaking, for different kinds of CDs, high-security-grade deletion or erasure of data from CDRs is the most difficult to accomplish. CDRWs are the modern equivalent of floppy disks. Actual writing is by a laser, and the stored data is covered by a metallized reflective layer which is the back side of the label. Rewriteables tend to have the reflective label come off in flakes. Also, there is a remote possibility that a mirror image of the data might come off with the label. Flakes are big enough fragments that such data might still be read. Ordinary CDs, CDRs and CDRWs are sometimes collectively referred to herein as CDs. DVDs (digital versatile disks, also previously known as “digital video disks”) are almost exactly the same thickness, diameter, and general shape as CDs and in many ways resemble CDs. Generally a disk can be determined to be a DVD by the edge having a central seam or joint between the two halves.
DVDs are manufactured somewhat like a sandwich, with an extremely thin reflective layer and one or two extremely thin layers of a special light-sensitive dye in the middle, located between the two thick clear plastic covers. A “double-sided” DVD can hold twice as much data as the equivalent-type “single-sided” DVD.
A “single-sided” DVD consists of a thick clear plastic cover, an extremely thin dye layer, an extremely thin reflective layer and a thick clear plastic cover. The read/write laser “looks through” and “shoots through” the clear plastic towards the data layer and finally the reflector layer, from ONE side.
A “double-sided” DVD consists of a thick clear plastic cover, an extremely thin dye layer, an extremely thin reflective layer which is reflective on both sides, an extremely thin dye layer, and a thick clear plastic cover. The read/write laser “looks through” and “shoots through” the clear plastic towards the data layer and finally the reflector layer from EITHER side, thus providing double storage capacity.
Currently, in the year 2001, the highest commercially available DVD (“double-sided”) capacity is about 9.4 gigabytes, with even higher capacity DVD's on the horizon. The highest capacity CD is currently about 0.8 gigabytes. With their vastly superior storage capacity one can only conclude that DVD's will become increasingly popular.
Destruction of data from such CDs and DVDs may be further complicated by the fact that particular manufacturers may use different adhesive systems, with some systems more prone to flaking upon removal of the data layer. Thus, flaking is a variable problem for which provision must be made, but which is not easily solved, when undertaking data removal.
In certain applications, erasing or removing sensitive data from disks can be critical for security reasons or necessary for business reasons. As devices for putting information onto disks such as CDs and DVDs are becoming more common, so, too, the problem of how to effectively remove that stored information from the disks is becoming even more of a concern.
Certain devices for performing such data erasure are known, but respectively suffer from drawbacks.
For example, Proton Engineering Inc. has a declassification system that is a CD-ROM Eraser/Declassifier, for CD-ROMS, WORM CDs and other optical media, that according to its literature reportedly declassifies CD-ROMS in 12 seconds. It is a mini-tower of 18″×18″×9″, 75 lbs, and its power requirements are 120 vac. 50/60 Hz., 8 amperes. Another example of a known data-erasure device is SEM's model 1200 weighing 75 lbs. The DX-CDE CD destruction device is 59.4 lbs, 24″ high, 7.5″ in diameter, weighing 50 lbs. with electrical operation. These declassification machines, weighing 75 lbs, almost 60 lbs and 50 lbs, disadvantageously are relatively heavy and not easily portable. A further example is the DX-CDm™ CD Destruction Device, which is a manual field portable unit that is intended for mounting on the inside wall of a vehicle, bracketed to the side of a vessel, or securely fastened to the bulkhead of an ocean going vessel. The machine is 20 lbs, 10″ high, of 7″ diameter. The inner hub of the erased disk remains intact. The machine operates by mechanical operation with a rotating handle. Although this declassification machine is relatively light-weight, 30 seconds is the operating time, which may be disadvantageously long. In addition, this machine disadvantageously MUST be firmly secured to a robust mounting surface, because considerable force is exerted on the rotary handle to operate it. Further this machine disadvantageously requires considerable manual effort, resulting in rapid operator fatigue, and consequent difficulty in performing the critically important high-security-grade removal of data.
Another conventional device that purports to provide secure CD destruction is that of U.S. Pat. No. 6,039,637 to Hutchison et al. (issued Mar. 21, 2000) for “Security device for destroying the information bearing layer and data of a compact disc.”
Another example of a device that purports to provide secure CD destruction is that of U.S. Pat. No. 6,189,446, to Olliges et al. (issued Feb. 20, 2001) is for a “System for the secure destruction of compact disc data.” Olliges discloses a system for use on gold or aluminum information bearing surfaces (IBS's), especially those of CDs but also mentioning DVDs. Olliges et al.'s system includes at least one pair of rollers, with each roller rotatably mounted between rigid support plates. A CD passes between the rollers under pressure. The roller exteriors contain raised patterns. After passing through the roller system, the disk is said to be characterized by lines of distortion that are about 0.25 mm apart. Olliges et al. attempts to distort a CD sufficiently to prevent a laser from reading information stored in groove-like patterns, by distorting the shape of pits in which data were stored, moving pits from their original positions, displacing the reflective layer of the CD at the base of the pits so that the laser beam does not reflect back properly to the optical sensor, “filling in” the pits, and production of imperfections. Such a method that leaves data on the disk is subject to drawbacks, such as the fact that there may be technology, now or developed in the future, for making sense of the remains. Especially where so much data is all in one place (e.g., still on the one disk), Olliges et al.'s methods may be risky.
A commercial example of such a machine is the Security Engineered Machinery (SEM) Model 1250B. Examination of the results of the operation of this machine reveals that it disadvantageously leaves considerable contiguous recorded information, easily visible under an ordinary microscope, on the disk. Thus it disadvantageously does not perform the high-security data removal to Dept. of Defense standards, or even common-sense industrial security standards.
Another consideration introduced into this data destruction area is that in many applications the declassified disk cannot be entirely destroyed, because verification of declassification is needed for the particular exact original disk. Such verification is accomplished by a data destruction method that retains only the disk's inner-hub which bears its identifying information, such as a serial number. A method which destroys the en
Rosenbaum Mark
Whitham Curtis & Christofferson, P.C.
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