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EMP--electromagnetic pulse -- is a threat too huge to contemplate. It can wipe out all electronic data in a nanosecond: bills, assets, credits, debits--puff, gone! What is left, believe it or not, is old fashioned paper, which remains totally unaffected, oblivious to the rays of death that choke and convolute every computer and all electronic data storage.

Paper documents are a nuisance, but they are not without their charm especially now in the light of new threats. Indeed, paper may prove the difference between a fatal business catastrophe and a bounceback challenge. Papers have an original (only one), and copies (many), and the two are distinguishable! The original cannot be stolen while remaining in the possession of its rightful holder--unlike electronic documents.

To be sure, from the point of view of theoretical risk analysis, papers face a series of risks: they can be burnt, shredded, eaten by mold, or fade away. However, these risk factors are non-overlapping with the risks faced by electronic data, and hence paper backup is a sound strategy.

Recently a financial officer pointed out to me a paper advantage I never thought about. When Hurricane Katrina approached, he instructed his people to remove sensitive financial documents to a safe place. In the panic that prevailed, the accountants could not find where on the hard drives the sensitive data resided, and they had to wait for the IT guru. His secretary, by contrast, simply pulled the important files from the locked file cabinets.

Yet, until recently, electronic documents had an edge when it came to combating forgery. An electronic file can be signed with a very short bit string (a hash signature). If even a single bit changes in the file, then when one re-computes its signature, it deviates from the attached one. And thus by sending over an electronic file with its signature attached, the sender is assured that no man-in-the-middle can convincingly forge that file, because the forgery would be caught by inspecting the signature.

This assurance was nonexistent with paper documents. The check you send in the mail, the financial letter you send to your bank, may be forged on their way to their destination. And, what's more, you don't need a degree in computer science to change the legal amount on a check from "one thousand dollars" to "twenty-one thousand dollars." You just need a suitable color pen and a criminal mind.

In the near future, though, check fraudsters will have to reinvent themselves because paper technology is making a critical move. Checks, statements, letters of credit, or any such paper document will be affixed with a two-dimensional bar-coded label that will capture a condensed version of the image on the page. Should a forger add a zero to a check, then when the check is scanned, and the scan is condensed and compared to the affixed label, the mismatch will sound an alarm.

This paper-integrity technology will help launch a comeback for paper media and will deprive mystery writers of an entire genre of juicy plots. What is not clear is how soon this anti-forgery tool will come of age. One difficulty is that every time you scan a page, its position shifts, however slightly, so that the bit-string of the scan is different, and hence the hash-signature is different. And then the software must be intelligent enough to distinguish a coffee stain, a stapler hole, an added bit of text, or an erased digit.

A bridge technology, though, is available right now: the key data on a paper document (dollar figures, dates, ID numbers) may be combined into a numeric string and then mapped into a unique graphic image, which is stamped on the paper. Anyone can recompute that graphic from the data on the page. If those data change, then the resulting graphic will change, too.

Another very promising technology is poised to make paper a durable medium in this fast-track electronic age. High-tech ink comes with dating markers. This means that the paper will carry evidence of the date it was printed. A counterfeit or forgery would stand out through this dating evidence.

You can't compose a romantic poem with a keyboard and a screen, argues a poet I know. Only a fountain pen and an old notebook will do. You don't need to be a poet to appreciate the tangibility and the old-fashioned charm of paper. Though the electronic-transactions industry is all about the conversion of paper to electronic formats, most of us, I presume, would cheer on this old-technology medium as a helpmate in the battle against fraud.