Barnes & Noble is making it known today that it has detected tampering with PIN pad devices used in 63 of its stores. The retailer made it clear that as soon as evidence of tampering was detected, it discontinued use of all PIN pads in its nearly 700 locations throughout the U.S.

However, the number of PIN pads confirmed to be compromised seems limited to one for each of the 63 reported locations.

Barnes & Noble of course notified federal law enforcement authorities and is currently supporting a federal investigation into the matter.

The company's own internal investigation, which involved inspecting and validating every PIN pad in every store, however, found that fewer than 1 percent of PIN pads were compromised in a "sophisticated criminal effort" to steal credit card information, debit card information, and debit card PIN numbers. 

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As such, only purchases made with cards swiped through PIN pads may result in customer information being compromised.

Barnes & Noble stressed, however, that its customer database is secure, so purchases made on Barnes & Noble.com, Nook and Nook mobile apps were not affected. Furthermore, none of the affected PIN pads were discovered at Barnes & Noble College Bookstores.

Aside from working with federal law enforcement authorities, Barnes & Noble is working with banks, payment card brands and issuers to identify accounts that may have been compromised, allowing banks and issuers to employ enhanced fraud security measures on accounts potentially affected.

Apparently bugs planted in the tampered PIN pad devices allowed criminals to potentially capture credit card and PIN numbers.

In September, Barnes & Noble announced the pending release of two new tablets to join its selection of ereaders. These new devices, the Nook HD and Nook HD+, are to run on Google's popular Android (News - Alert) mobile OS just as Amazon's Kindle Fire devices do.

However, there are apparently plans to release tablets running on Microsoft's Windows 8 in the future as well.