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+--- Thread: [Wired] Sleuths Read Old Booby-Trapped Letters Without Opening Them (/Thread-Wired-Sleuths-Read-Old-Booby-Trapped-Letters-Without-Opening-Them)
[Wired] Sleuths Read Old Booby-Trapped Letters Without Opening Them - Wired Magazine - 2021-03-10
Sleuths Read Old Booby-Trapped Letters Without Opening Them
People once folded their correspondence in intricate ways, known as “letterlocking,” to keep out snoops. A fancy new imaging technique sees right through it.
https://www.wired.com/story/sleuths-read-old-booby-trapped-letters-without-opening-them