A deliberate typo could act like a hidden fingerprint
A printer could leave a small, intentional error in a document’s original text—a misplaced letter or a grammatical slip that looked ordinary enough to escape notice. The mistake was useful precisely because it was not an obvious mark of security. It was a tiny feature that someone familiar with the genuine document could later check.
The trick worked when a forger copied the document but “fixed” the wording. A copy with flawless grammar might seem more trustworthy at first glance, yet that correction removed the clue present in the authentic version. The suspiciously perfect copy could therefore reveal that someone had recreated the text rather than reproduced the original.
Why a flaw could protect the document
This was a low-tech way to make copying risky. A visible seal or signature could be imitated; a subtle error was harder to recognize as important if the copier did not know it had been planted. The person checking the document did not need to spot sophisticated printing equipment or prove who made the copy. They only needed to compare the wording against the known original.
The method depended on secrecy and careful comparison: if a forger knew the error, they could preserve it, and if the authentic text was not available, the clue was harder to use. But a correction meant as an improvement could become evidence against the copy. In this case, the typo was not merely a mistake—it was part of the document’s defense.
