Learn How Richard Feynman Cracked the Safes with Atomic Secrets at Los Alamos

The sto­ry has become part of physics lore: A young Richard Feyn­man, future Nobel win­ner, was bored with life in the remote New Mex­i­co desert while work­ing on the atom­ic bomb dur­ing World War II, so he amused him­self by learn­ing to pick the com­bi­na­tion locks in the sup­pos­ed­ly secure fil­ing cab­i­nets con­tain­ing Amer­i­ca’s nuclear secrets. As Feyn­man would lat­er write in his essay, “Safe­crack­er Meets Safe­crack­er”:

To demon­strate that the locks meant noth­ing, when­ev­er I want­ed some­body’s report and they weren’t around, I’d just go in their office, open the fil­ing cab­i­net, and take it out. When I was fin­ished I would give it back to the guy: “Thanks for your report.”

“Where’d you get it?”

“Out of your fil­ing cab­i­net.”

“But I locked it!”

“I know you locked it. The locks are no good.”

So the offi­cials at Los Alam­os installed cab­i­nets with bet­ter locks. But Feyn­man stud­ied the new ones sys­tem­at­i­cal­ly, and even­tu­al­ly, giv­en a lit­tle time, he could open any lock at will. As a joke, he left a note in one cab­i­net that said, “I bor­rowed doc­u­ment no. LA4312–Feynman the safe­crack­er.”

I opened the safes which con­tained all the secrets to the atom­ic bomb: the sched­ules for the pro­duc­tion of the plu­to­ni­um, the purifi­ca­tion pro­ce­dures, how much mate­r­i­al is need­ed, how the bomb works, how the neu­trons are gen­er­at­ed, what the design is, the dimensions–the entire infor­ma­tion that was known at Los Alam­os: the whole schmeer!

To learn a bit about how Feyn­man did it, watch this fas­ci­nat­ing lit­tle video by jour­nal­ist Brady Haran of the YouTube-fund­ed Num­ber­phile. Haran inter­views Roger Bow­ley, emer­i­tus pro­fes­sor of physics at the Uni­ver­si­ty of Not­ting­ham, who explains sev­er­al of the inge­nious meth­ods used by Feyn­man to solve the prob­lem of crack­ing a lock with (sup­pos­ed­ly) a mil­lion pos­si­ble com­bi­na­tions. And to learn more about Feyn­man’s adven­ture as a safe­crack­er, be sure to read “Safe­crack­er Meets Safe­crack­er,” which is includ­ed in his book Sure­ly You’re Jok­ing, Mr. Feyn­man! and can be read on PDF by click­ing here.

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Relat­ed Con­tent:

Free: Richard Feynman’s Physics Course from Cor­nell (1964)

Richard Feynman’s Ode to a Flower: A Short Ani­ma­tion