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The clever folds that kept letters secret (bbc.com)
33 points by robalicious 1832 days ago
3 comments
hoppyhoppy2 1832 days ago
Previously on HN:

https://news.ycombinator.com/item?id=26532134

https://news.ycombinator.com/item?id=26555153

https://news.ycombinator.com/item?id=18420924

https://news.ycombinator.com/item?id=26338673

https://news.ycombinator.com/item?id=26327888

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trabant00 1832 days ago
After watching the video I do not understand what prevents anybody from reversing the strip through the hole after drying it.
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bombcar 1832 days ago
It doesn’t prevent observation - it provides evidence that it was observed. Likely with a ton of effort and careful application of steam, etc you could defeat it - but it’s more designed to prevent casual snooping.

So don’t think PGP encrypted but think a URL that records who views it.

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BrandoElFollito 1832 days ago
Why is it difficult to undo, then redo? Obviously one need to be careful (twice) but that's all
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bombcar 1832 days ago
The key is the adhesive which means you have to tear or otherwise undo it before you can unfold it.

I suspect that much of it was simply “how can we fold the letter” taken to extremes as a form of individual expression.

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devenson 1832 days ago
Perhaps wetting and mashing it down changes its shape and strength so it's too delicate to reverse.
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ksaj 1832 days ago
I picture it like being more complex than re-folding a street map. It seems a good lot of people mess that up, and it's easy to tell it's happened because some of the folds go the wrong way, and sometimes there are new folds and "puffy" edges that don't belong there.

Just like ironing, where sometimes you see an erroneous V-shaped pleat running down the front of an otherwise impeccable pair of dress pants.

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smiley1437 1832 days ago
That's a lot of faith in the strength of a small strip of paper, I'd probably rip the thing several times just trying to make it like the video

Did they have stronger paper back then?

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sbradford26 1832 days ago
Making paper was a lot harder back then and they didn't have the machinery to create the uniform thin paper we have now. So you ended up with a thicker paper with more variance.
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bombcar 1832 days ago
I assume they did but costs were associated - considering they were avoiding envelopes.
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