There was a time when you could just go out and buy an Enig­ma machine. In the ear­ly nine­teen-twen­ties, any orga­ni­za­tion with a need to keep its com­mu­ni­ca­tions secret could order a few of those brand-new devices from Ger­many and rest assured that any mes­sages encod­ed using them would be safe from pry­ing eyes. It did­n’t take long for the mil­i­tary to catch on to the Enig­ma’s use­ful­ness. Just a few years after the machine came on the mar­ket, it had been adopt­ed by the Ger­man Navy, Army, and Air Force, and made pos­si­ble the rapid, secret coor­di­na­tion cen­tral to the tech­nique we now call blitzkrieg. When World War II began, Axis forces were con­fi­dent, as any­one in pos­ses­sion of an unbreak­able code might well be.

As his­to­ry played out, of course, that code turned out to be break­able. That this came as a sur­prise to the Nazis makes sense if you watch the new video above from Ver­i­ta­si­um, which opens up an actu­al Enig­ma machine and explains its inner work­ings. Each let­ter typed into its key­board pass­es through a series of inter­change­able rotors wired togeth­er, then comes back through in the oppo­site direc­tion, result­ing in a par­tic­u­lar sub­sti­tute let­ter.

Each char­ac­ter entered advances at least one of the rotors, each of which turns at a dif­fer­ent speed, mean­ing that the already com­plex sub­sti­tu­tion cipher con­stant­ly changes. To make it even trick­i­er, the Nazis made mod­i­fi­ca­tions to their Enig­ma machines, includ­ing a tele­phone-oper­a­tor-style plug­board that expand­ed the pos­si­ble encryp­tion keys to 7 x 10¹⁸: an infi­nite-seem­ing num­ber that fair­ly cried out for the math­e­mat­i­cal ser­vices of Alan Tur­ing.

Already famous for hav­ing come up with the “Tur­ing machine,” which could the­o­ret­i­cal­ly manip­u­late strings of sym­bols in what we’d now call an algo­rith­mic fash­ion, he was recruit­ed by Britain’s wartime code­break­ing head­quar­ters at Bletch­ley Park, where experts were already hard at work reverse-engi­neer­ing the Enig­ma machine. There he con­sid­ered flaws in the design of the device, such as its inabil­i­ty to encrypt any giv­en let­ter as itself, and the ways in which its human oper­a­tors used it, such as mak­ing pre­dictable weath­er reports. Exploit­ing these weak­ness­es required build­ing a non-the­o­ret­i­cal com­pu­ta­tion engine, the Bombe, to grind through all pos­si­bil­i­ties at what would then have seemed an unfath­omable speed. The intel­li­gence the Bombe pro­duced con­tributed to the suc­cess of the sur­prise D‑Day inva­sion and may have tak­en years off the poten­tial rav­ages of World War II. It would­n’t have hap­pened with­out Tur­ing’s for­mi­da­ble intel­li­gence — or his under­stand­ing that you need a machine to out­smart a machine.

Relat­ed Con­tent:

The Enig­ma Machine: How Alan Tur­ing Helped Break the Unbreak­able Nazi Code

How British Code­break­ers Built the First Elec­tron­ic Com­put­er

The LEGO Tur­ing Machine Gives a Quick Primer on How Your Com­put­er Works

A Tur­ing Machine Hand­made Out of Wood

Can You Crack the Uncrack­able Code in Kryp­tos, the CIA’s Work of Pub­lic Art?

The Sto­ry of Elize­beth Fried­man, the Pio­neer­ing Cryp­tol­o­gist Who Thwart­ed the Nazis & Got Burned by J. Edgar Hoover

Based in Seoul, Col­in Marshall writes and broad­casts on cities, lan­guage, and cul­ture. He’s the author of the newslet­ter Books on Cities as well as the books 한국 요약 금지 (No Sum­ma­riz­ing Korea) and Kore­an Newtro. Fol­low him on the social net­work for­mer­ly known as Twit­ter at @colinmarshall.

One often-repeat­ed anec­dote about Mil­ton Fried­man has the famous econ­o­mist vis­it­ing a canal under con­struc­tion in nine­teen-six­ties Chi­na. Notic­ing the sheer num­ber of human labor­ers dig­ging away with shov­els, he asked the offi­cial in charge why they weren’t get­ting the work done faster with exca­va­tors and oth­er mod­ern machines. The bureau­crat explained to him that doing it by hand cre­at­ed more jobs. Fried­man’s reply: “If it’s jobs you want, you should give those men spoons instead.” Whether or not this exchange ever actu­al­ly hap­pened, it illus­trates a con­flict that’s arisen more than once in the his­to­ry of civ­i­liza­tion, pos­si­bly since the dawn of indus­tri­al­iza­tion — and at least since the hey­day of the Lud­dites.

Accord­ing to the Uni­ver­si­ty of Cam­bridge, that hey­day came in 1812, the year of “an assault by some 150 armed labor­ers on a Hud­der­s­field mill, in which sol­diers opened fire on the mob to stop them break­ing into the premis­es, fatal­ly wound­ing two attack­ers.” This was the cul­mi­na­tion of a series of protests across Eng­land, all of them inspired by anger at “new tech­nolo­gies, like auto­mat­ed looms, which were being used in the tex­tile indus­try in place of the skilled work of arti­sans, threat­en­ing their liveli­hoods as a result.” These des­per­ate­ly infu­ri­at­ed pro­test­ers, whose doc­u­ment­ed actions include the mur­der of a York­shire mill own­er, loud­ly expressed alle­giance to one Ned Ludd, a weaver said to have tak­en the bold step of smash­ing a cou­ple of new­fan­gled stock­ing frames some 25 years before.

The sto­ry of Lud­d’s ear­ly stand against mech­a­niza­tion may be even more ques­tion­able than the one about Mil­ton Fried­man and the spoons, but his name sur­vives today nev­er­the­less. In fact, it’s under­gone some­what of a revival thanks to the arti­fi­cial-intel­li­gence boom of recent years, dur­ing which even the mod­ern “knowl­edge work­ers” have come to fear the tram­pling of their liveli­hoods under tech­nol­o­gy’s inex­orable march. Their calls for restric­tions on the devel­op­ment and deploy­ment of AI are, in one side’s fram­ing of the argu­ment, mere­ly the lat­est pub­lic spasm of Lud­dism, a move­ment explained in the video above from The His­to­ry Guy. How many here in the twen­ty-first cen­tu­ry, after all, would argue that the mass pro­duc­tion of socks ulti­mate­ly con­sti­tut­ed a real loss for human­i­ty?

Lud­dism nev­er did count a large pro­por­tion of the Eng­lish labor force as its own. Rather, the move­ment appealed to “a rel­a­tive­ly ‘elite’ group” of legal­ly pro­tect­ed work­ers only allowed into their pro­fes­sions after years of appren­tice­ship, at which point “they tend­ed to feel that they were owed a liv­ing.” Nor did the con­di­tions, hours, and com­pen­sa­tion at the fac­to­ries then spring­ing up seem favor­able com­pared to the way of life enjoyed by their pre­de­ces­sors. Sim­i­lar sen­ti­ments may under­lie the “Lud­dite clubs” form­ing on col­lege cam­pus­es, on which NPR has report­ed, or this year’s social media-free “Sum­mer of Ludd” at the New School, to say noth­ing of ongo­ing protests against data-cen­ter con­struc­tion. It would be fas­ci­nat­ing to hear what gen­uine nine­teenth-cen­tu­ry Lud­dites would make of our sit­u­a­tion. Per­haps, one day, we can use AI to res­ur­rect them.

Relat­ed con­tent:

Hear Alan Watts’s 1960s Pre­dic­tion That Automa­tion Will Neces­si­tate a Uni­ver­sal Basic Income

Experts Pre­dict When Arti­fi­cial Intel­li­gence Will Take Our Jobs: From Writ­ing Essays, Books & Songs, to Per­form­ing Surgery and Dri­ving Trucks

The Inge­nious Engi­neer­ing of Silk: How the 2,000-Year-Old Pat­tern Loom Pow­ered the Silk Road and the Wealth of Ancient Chi­na

How Qatar Built Sta­di­ums with Forced Labor

Based in Seoul, Col­in Marshall writes and broad­casts on cities, lan­guage, and cul­ture. He’s the author of the newslet­ter Books on Cities as well as the books 한국 요약 금지 (No Sum­ma­riz­ing Korea) and Kore­an Newtro. Fol­low him on the social net­work for­mer­ly known as Twit­ter at @colinmarshall.