Three hundred years ago, before envelopes, passwords and security codes, writers often struggled to keep thoughts, cares and dreams expressed in their letters private. One popular way was to use a ...

Opening a letter may seem like a straightforward task, but that’s only in the age of mass-produced gummed envelopes, first invented in the 1830s. For hundreds of years before that, many people relied ...

Until the 1830s, letters sent around the world were secured through a method called “letterlocking,” in which the paper was folded so intricately that opening it up broke the folds, or the “seal,” ...

M.I.T. researchers have devised a virtual-reality technique that lets them read old letters that were mailed not in envelopes but in the writing paper itself after being folded into elaborate ...

A rare unopened example of a letterpacket with a paper lock. This locking mechanism was used since the 1500s, but until now, only opened and “unlocked” examples had been seen in archival collections.

The WordLock is a combination lock that unlocks with a four-letter code word of your choosing, instead of a number code, and it’s aimed at travelers who need a lock but already have so many numbers ...

Three hundred years ago, before envelopes, passwords and security codes, writers often struggled to keep thoughts, cares and dreams expressed in their letters private. One popular way was to use a ...