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Paper shredders are used to cut paper into very fine strips or tiny paper chips. Government organizations, businesses, and private individuals use shredders to destroy private, confidential, or sensitive documents. Privacy experts often recommend that individuals shred bills, credit card and bank account statements, and other documents that could be used by thieves to commit fraud or identity theft.

After the Supreme Court decision in California v. Greenwood, in which the Supreme Court of the United States held that the Fourth Amendment does not prohibit the warrantless search and seizure of garbage left for collection outside of a home, paper shredders became more popular among US citizens with privacy concerns.

Contents 1 Types of shredders 1.1 Shredder trucks 2 Shredding services 3 Unshredding 4 Forensic identification 5 Injury risk with residential shredders 6 References 7 See also

Shredders range in size and price from small and inexpensive units meant for a few pages, to large units used by commercial shredding services that costs hundreds of thousands of dollars and can shred millions of documents an hour. Some shredders used by a commercial shredding service are built into a shredding truck.

These machines are classified according to the size and shape of the shreds they produce.

• Strip-cut shredders use rotating knives to cut narrow strips as long as the original sheet of paper. These strips can be reassembled by a determined investigator, so this type of shredder is the least secure. It also creates the highest volume of waste.
• Cross-cut or confetti-cut shredders use two contra-rotating drums to cut rectangular, parallelogram, or diamond-shaped shreds.
• Particle-cut shredders create tiny square or circular pieces.
• Disintegrators and granulators repeatedly cut the paper at random until the particles are small enough to pass through a mesh.
• Hammermills pound the paper through a screen.
• Pierce and Tear Rotating blades pierce the paper and then tear it apart.
• Grinders A rotating shaft with cutting blades grinds the paper until it is small enough to fall through a screen.

There are numerous standards for the security levels of paper shredders, including:

• DIN 32757
  • Level 1 = 12 mm strips
  • Level 2 = 6 mm strips
  • Level 3 = 2 mm strips (Confidential)
  • Level 4 = 2 x 15 mm particles (Commercially Sensitive)
  • Level 5 = 0.8 x 12 mm particles (Top Secret or Classified)
  • Level 6 = 0.8 x 4 mm particles (Top Secret or Classified)
• United States Department of Defense (DoD)
  • Top Secret = 0.8 x 11.1 mm (1/32" × 7/16")
• United States NSA/CSS 02-01 = 1 × 4 mm

Historically, the US General Services Administration (GSA) set paper shredder guidance in the Interim Federal Specification FF-S-001169 dated 7/1971 which was superseded by standard A-A-2599 for classified material which was canceled in 2/2000. GSA has not published a new standard since.

There are also alternative shredders that use burning, chemical decomposition, or composting for disposing of the shreds.

A mobile shredding truck is a box truck with an industrial sized paper shredder mounted inside the box, typically in the front section of the box, closest to the cab. The box is divided into two sections: the shredding equipment area, and the payload area for storage of the shredded materials. These trucks have been designed to shred up to 5,000 lbs of paper an hour. Mobile shredding trucks can have a shredded material storage capacity of 6,000 to 15,000 pounds of shredded paper. Office paper is the typical material being shredded, but with increasing security concerns customers also request shredding of CDs, DVDs, hard drives, credit cards, uniforms, among other things. Shred Tech of Ontario, Canada is the leading manufacturer of mobile shredding trucks and supplies much the United States, Canada and Europe.

Due to information privacy laws like FACTA and HIPAA, the volume of shredding at the typical business has increased dramatically. To reduce costs many companies outsource their shredding to shredding services. These companies either shred on-site, usually with mobile shredder trucks, or off-site. All shredded paper is then sent to a paper mill.

In some cases, it may be possible to reassemble the pieces of shredded documents. If the shreds are not disturbed, the "noodles" or particles that belonged to the same document tend to stay close to each other. Furthermore, when the documents are fed to the shredder in a way that the lines of text are not perpendicular to the shredder blades, portions of text may remain legible on the stripes.

Shredded documents can be reassembled manually. After the Iranian Revolution and the takeover of the U.S. embassy in Tehran in 1979, Iranians enlisted local carpet weavers who reconstructed the pieces by hand. The recovered documents would be later released by the Iranian regime in a series of books called "Documents from the US espionage Den". The US government subsequently improved its shredding techniques, by adding pulverizing, pulping, and chemical decomposition.

Modern computer technology considerably speeds up the process of reassembling shredded documents. The strips are scanned on both sides, and then the computer determines how the strips should be put together. Robert Johnson of the National Association for Information Destruction, has stated that there is a huge demand for document reconstruction. Several companies offer commercial document reconstruction services. For maximum security, documents should be shredded so that the words of the document go through the shredder horizontally (i.e. perpendicular to the blades). Many of the documents in the Enron accountancy scandal were fed through the shredder the wrong way, making them easier to reassemble.

There is an effort underway to recovery the shredded archives of the Stasi, the East German secret police.^[1] There are "millions of shreds of paper that panicked Stasi officials threw into garbage bags during the regime's final days in the fall of 1989". It took three dozen people six years to reconstruct 300 of the 16,000 bags so the German government is looking at modern computerized methods of reconstruction.

Document shredders display certain device-specific characteristics, "fingerprints", like the exact spacing of the blades, the degree and pattern of their wear. These can be reconstructed from the minute variations of size of the paper strips and the microscopic marks on their edges, and by comparison with the strips produced by known shredders, the individual shredder that was used to destroy a given document may be determined. Jack Brassil, a researcher for Hewlett-Packard, works on a project for making shredders more easily traceable.^[2] (Cf. the forensic identification of typewriters.)

As with any motorized cutting equipment, there is a risk of injury. Small residential shredders are becoming more and more common. These shredders, although designed with a narrow opening to the cutting wheels, still pose a danger to pets and small children. Many home shredders can be left in a "stand-by" mode that will start the cutting process when anything is inserted into the feed slot. In homes with small children or pets, simply keeping the shredder unplugged while not in use can greatly reduce any risk. ^[3]

1. ^ Heingartner, Douglas. "Back Together Again", New York Times, 2003-07-17. Retrieved on January 3, 2007.
2. ^ Jack Brassil (2002-08-02). "Tracing the Source of a Shredded Document" (pdf). Hewlett-Packard. Retrieved on 2007-01-03.
3. ^ Eureka Alerts, Urban Legends Page

• Identity theft