Lenovo explores US patent blockchain for document validation

A new patent that has been filed by Lenovo suggests the company is exploring the use of blockchain as a way to validate documents

Marcus Zallman
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A new patent that has been filed by Lenovo suggests the company is exploring the use of blockchain as a way to validate documents. The patent describes tech that could be used to authenticate physical documents that are tagged with digital signatures.

The patent was first submitted in 2016 but was only granted by the U.S. Patent and Trademark Office last week. As spotted by CoinDesk, the patent uses blockchain technology as the basis of a new verification method for physical documents. Although many organisations are going paperless, physical documents remain essential to businesses and governments across the world.The technology works by encoding a digital signature into documents. By using this encoding instead of a physically printed mark, the recipient can be confident the document was not modified after it was created.

Lenovo creates an "integrity map" for the document from an "integrity symbol" – such as a digital signature – within it. The processor can then compare a new copy of the physical document to the integrity map, enabling determination of whether the printout is genuine.The integrity map is added to a blockchain so that recipients can verify the integrity of physical documents when they are received.

Taking a picture of a document can be used to build its integrity map, which can then be compared with the integrity map known to be associated with the original.

The mechanism provides a way for recipients to know they have a genuine document, even if multiple fraudulent ones exist. Forgeries will appear as orphaned blocks in the blockchain, so will fail validation when the user scans the code.

Recipients are always assured they have an authentic document, eliminating the possibility that the information within is inaccurate.

Fraudulent modifications

The issue Lenovo's trying to solve is the potential to modify a printed document after it has been signed with ink. In the patent's abstract, Lenovo notes that organisations need assurance that documents aren't modified. However, most are reluctant or unable to go fully-digital so they do not use cryptographic signatures.

This presents a need for technology that prevents tampering with physically printed documents after they've been signed. "When a paper document is physically signed with an ink pen and then scanned, faxed or emailed, there is no assurance that the text of the document was not substantially altered after the signature was applied," said Lenovo. "A wide range of digital signature technologies exists today, but they do not provide tamper-proof mechanisms for verifying physical documents printed with physical ink."

It's unclear as to whether Lenovo has worked to actively develop the technology since filing the patent 18 months ago.

A device using the principles could be of value to large-scale organisations which frequently handle sensitive paper documents. It's also another example of the increasing diversity of blockchain applications, including to physical items that are usually considered to be "offline."