2021年经济学人 黑客秘史--撬开一堆17世纪的信件（在线收听）

Hacking history

黑客史

Origami in reverse

逆向折纸

Cracking the security on a trove of 17th-century letters

撬开一堆17世纪的信件

A modern correspondent wanting to communicate privately can use computerised encryption. Three hundred years ago, origami would have been a better bet.

想要私下沟通的现代通讯记者可以使用计算机加密。三百年前，折纸可能是个更好的选择。

Before gummed envelopes became common in the 1800s, letters were posted with no security wrapper. Privacy-minded writers relied instead on cunning combinations of folds, tucks, slits and seals, a practice Jana Dambrogio at the Massachusetts Institute of Technology has dubbed "letterlocking".

在19世纪涂胶信封普及之前，信在投递时并没有安全性包装。注重隐私的作家们转而依靠巧妙的折叠、褶子、缝和封条的组合，麻省理工学院的让娜·丹布罗吉欧称之为“信锁”。

Some, like the "chapel fold", in which the letteris turned into its own envelope and sealed, were the equivalent of simple padlocks. Others were subtler. The "dagger trap"relied on a concealed wax seal that would leave a telltale rip once a letter had been opened.

有些就像“教堂褶”，把信放进信封并密封起来，就像简单的挂锁一样。“匕首陷阱”依赖于一个隐藏的蜡封，一旦信被打开，就会留下一个泄密的裂口。

But information about the practice is scarce. Most historical letters survive in their opened form, leaving aficionados like Ms Dambrogio with little to go on but crease-marks and tears. The few that remain unopened present a different problem: how to read them without permanently damaging the letterlock. Now, in research published in Nature Communications, Ms Dambrogio and her colleagues have come up with a solution.

但是有关这种做法的信息很少。大多数历史文献以公开形式保存下来，这让像丹布罗吉奥这样的爱好者除了折痕和裂缝外几乎没有任何进展。少数未开封的信件则呈现出另一个问题：如何在不损坏信锁的情况下读信。目前，在《自然通讯》上发表的一项研究中，丹布罗吉奥女士和她的同事们想出了一个解决方案。

The letters in question are part of the Brienne Collection, a trove of thousands of undelivered 17th-century letters bequeathed to posterity by Dutch postmasters. The collection includes 577 unopened, letterlocked missives. To get at their letters' contents while preserving the integrity of the locks, the team turned to X-rays and computers.

这些信件属于布蕾妮的藏品，这些藏品是荷兰邮政局长留给后人的数千封17世纪未投递的信件。藏品中包涵577封未开封的信件。为了在保持信锁的完整性的同时读取信件的内容，该团队使用了X光和电脑。

The key lay in knowing that the inks used at the time often contained iron. This meant that an X-ray microtomography scanner, of the kind usually reserved for distinguishing teeth or bone from soft tissue, could reliably distinguish the metallic letters from the paper background. Once the scan had also revealed the topography of the sheet, with the location of folds and creases mapped, the resulting model could be virtually unfolded by a computer to reveal the hidden text.

关键在于知道当时使用的墨水中通常含有铁。这意味着，通常用于区分牙齿、骨头和软组织的X光显微断层扫描仪能可靠地从纸张背景中分辨出金属字母。扫描一旦显示出纸张的的形态，并标出褶皱和折痕的位置，那么可以通过计算机将得到的模型展开来揭示隐藏的文本。

Though some imperfections remain—a hole left by a burrowing worm, for example, or the dry scratch of an ink-free nib—the legibility of the scans rivalled anything one would find in a research library, says Dr Starza Smith, a researcher at King's College London. And although no spectacular secrets have yet emerged from the Brienne Collection, the technique seems to hold plenty of promise for future research into a fascinating historical practice.

伦敦国王学院的研究人员斯塔扎·史密斯博士说，尽管还存在一些缺陷——例如，穴居虫留下的洞，或者无墨水笔尖上的干划痕——但扫描结果的易读性比得上在研究图书馆里找到的任何东西。虽然还没有从布蕾妮的藏品中发现什么惊人的秘密，但这项技术似乎为未来研究这一迷人的历史实践提供了很多希望。