Cicada 3301 First Puzzle Walkthrough | Boxentriq (2024)

This is a detailed and complete walkthrough/solution/writeup of the first Cicada 3301 puzzles and links to the tools you need to decode it. The Cicada 3301 is describes as one of the eeriest and strangest unsolved mysteries of the internet.

• Introduction
• The Invitation
• The Quest for the Holy Grail
• The Phone Call
• The Countdown
• Across the Globe
• Into The Dark
• The RSA puzzle
• The MIDI puzzle
• The End

Introduction

Cicada 3301 has been described as "the most baffling and enigmatic mystery on the Internet" and was listed as one of the "top 5 eeriest, unsolved mysteries of the internet" by Washington Post. On three occasions, Cicada 3301 has posted spectacular puzzles on the internet and dark web, with the stated intent of "recruiting intelligent individuals".

There has been much speculation and theories about Cicada 3301, including that they are recruitment tools for the NSA, MI6, Illuminati, a cult or a hacker group. Many first thought Cicada 3301 was an Alternate Reality Game, but still very few known where this rabbit hole leads to. Those who do have disappeared from the internet.

Puzzlers are still working on solving the Cicada 3301 Liber Primus ("First Book" in Latin), a book of encrypted runes. The pages which have been solved so far are available here.

The last public, and verified, communications from Cicada 3301 was in April 2017:

Beware false paths. Always verify PGP signature from 7A35090F. 3301

The Invitation

On January 5th, 2012, a mysterious image was posted on 4chan's /x/ - Paranormal board:

There was indeed a message hidden in this image. You can download the image and try yourself with Boxentriq's Text Extractor tool. See the screenshot below:

The text about TIBERIVS CLAVDIVS CAESAR indicates that the following text is a Caesar Cipher. Indeed, you can use Boxentriq's Caesar Cipher decoder to solve it:

To decode it, you will have to set the Shift to 4 and the Language to "Custom". It will then give a link to an Imgur image: https://i.imgur.com/m9sYK.jpg. This image however looks like a dead end:

Still it contains two keywords that hints on how to get the REAL message out: guess and out. This indicates that you should use the steganography tool OutGuess. If you use OutGuess, you get a much more interesting message:

Here is a book code. To find the book, and more information, go to https://www.reddit.com/r/a2e7j6ic78h0j/1:202:33:54:205:56:537:18:89:210:411:812:413:1314:415:816:417:518:1419:720:3121:1222:3623:224:325:526:6527:528:129:230:1831:3232:1033:334:2535:1036:737:2038:1039:3240:441:4042:1143:944:1345:646:347:548:4349:1750:1351:452:253:1854:455:656:457:2458:6459:560:3761:6062:1263:664:865:566:1867:4568:1069:270:1771:972:2073:274:3475:1376:21Good luck.3301

This message tells you that the numbers are a book cipher (also called a book code). A book cipher consists of numbers that references pages, paragraphs, lines, words or letters in a book. To decode it, you will need access to the book. The quest continued on Reddit.

The Quest for the Holy Grail

The forum on Reddit ("Subreddit") contained this image in the header, and also had the title a2e7j6ic78h0j7eiejd0120.

It also contained a lot of lines of text, and two images:

Using OutGuess on the welcome image gives this text:

-----BEGIN PGP SIGNED MESSAGE-----Hash: SHA1- From here on out, we will cryptographically sign all messages with this key.It is available on the mit keyservers. Key ID 7A35090F, as posted in a2e7j6ic78h0j.Patience is a virtue.Good luck.3301-----BEGIN PGP SIGNATURE-----Version: GnuPG v1.4.11 (GNU/Linux)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fRcg-----END PGP SIGNATURE-----

This is VERY important information, since there are many imposters pretending to be Cicada 3301. This PGP (GnuPG) key is how to verify their autenticity. Only real messages from Cicada 3301 are signed with this key ID: 7A35090F. Using this ID, their public key can be downloaded from the MIT keyserver.

The second image on the Subreddit looked like this:

It is a stereogram image, containing an image which looks similar to a Holy Grail. It also contains a OutGuess hidden text:

-----BEGIN PGP SIGNED MESSAGE-----Hash: SHA1The key has always been right in front of your eyes.This isn't the quest for the Holy Grail. Stop making it more difficult than it is. Good luck.3301-----BEGIN PGP SIGNATURE-----Version: GnuPG v1.4.11 (GNU/Linux)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*g6/vjGjo1VVUxn6HX9HKxdx4wYGMP5grmD8k4jQdF1Z7GtbcqzDsxP65XCaOYmray1JyFG5OlgFyOflmjBXHsNad=SqLP-----END PGP SIGNATURE-----

In the Subreddit were also many text lines, which looked like encrypted text:

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Sbw ghf Mixi klgz la ztvei. Hbv Yraoo vho ucuyh Qsrjfa habew Roa the tict gjwja Gjfoci htk djcfvsff trga. "P,dqc, dbrd thdv tal ugcw gamg wrkqo ak hdvuzsxk hg ax," fajf Kkk."Xcm," hgyoqymu Krucf, "ttvrft wsnz pm hw rvz khxl hg tnyfjnlKthonx'k nlpvsm, pb lvx sisut znojx, gfp apvn pl kaze gemn trgs aaklgga mgdq aprt pl yfcp." Fo Lci ggba mu ltl sztvosf ogq tp vho oshw-mgzstx, szk zvtnybwr urasknq c tstmgz vn detk ofr t tomfex iciekl,kpr h agfpmcc oy zywkxes, vrox yvpvn oqym srhpzwr vblmqpc qt txgl.Djsu mnwk hbv tal qgzebpt cnn dsntt la kzznd avw axnd. "Oqw," ccwkUcw, "pm ok fpuv fhy mgi mb gjxe wg af lzgdf." "Spnhu," gsww Bwbkn,"nq hoha hmf bf Ktp hzs mnlf vhkv wz aok pbm." "Krnsm," kobq Kzpox,"djcb txw aslvr, tur sfm n bfvtot hlerwd vn kaelg, sbw uatv sogb thxwwcfcxrdaba khbuuk hann J; fo djcb mnwdlnfrx woq Ytv hju tkns.""Lgupg zzkzmcf," jbclv Hjajp, "wsvv aak tqzb khta hzcn xnpyecv." 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Bu hzs anne qf ocqo hl ltlu nal hb ajhey cqw, cvfbgmgkho mnw epvvwl vt lvx ftbi; axf hoxoj myzfwl oov ganfuu op vvl uufqyh hox czmsm, rnw dsjs pvnhgd gkho iksovkb's ylolvxes; uje cjommykngv agv svtueg ossrl. Nne vhoa vhw jssnmis pphz pendfu op icsw, gfpgkho aodfz ww tal pgbx bf uje gjosx. Gfp apvy plfw gabouknq vvlbx vmnovrl."Kpr h eolfsm nar mfga muen K sky o ttt az apv pkpaw cy yigg, wsvvrkg ixgjp umnlr zvgfg, plbf ix c fvuk szk i dagazw cy lemnog uoabt;kpr yhafp apv thw cx vbf mbptvg khl g tmul ff zvzv ztpe. Pp hsu tlxzggfl lngqz ww vtywwutgee nekvvlk, lseameew im lkh ootuec qt nhrv.Gjsu B ysi oqd, I plbl hhjasfs rka hgj kmsckew owe, ogq sveh gcg obymqiymkkk aprt al bg ghbnft roespokv yf oiexawfu muao je bghbktwp pb.Kpr ox cwza ezta ts lcpnreu trg Qhlzdq. Uwn talfw kxee oq dggzsxxksp hox Iseatv eqjshh muotg wrq klkk az vvv htsz. Sbw ghfte S uodpqiy-ttv-fdmetr koegxys, fobbqwkxxazn artbu ol o pvneqw. Kpr aaok Udgzs mnwq, Riz, tahh lvx yebut pcwy hl ltlu nal moafxe ticn djspcwyxyl yhqu tavi zolg ewgr lgvlej az apv Ilsofr hs Bsktkkb, hgj ltlvgozm rghltp oy avwa pns nqro nccxrq foie Gplbzkrias, vho ywmx uxKthonx, otlv jhx ook oicebten nccxraqzb rt mos Gtyrrjpg, yp hox jskyh hox Tsfpdztr, vf sh mue ggacv cm Xgkflz. Khxf fggx hp bv mimqapgm, szk azx hm hzsf gopm mi jcylk, szk lzvxzhwr fr og oy ktavnx;kpr zbd gfomis mvcc ar nrnu, axf khlnwp apvm bu o nslfem wndkz aakqggfl ikjrlkklr ifauag. Aof trg hobxv epf jpklov qebtiu uzqb aakdcpsxy szk xieihfwr frau. Cnn vvl yumdap jiq acgy hsf na sykzlwqcftxtle, hvu pehqwr hghfts ercu fk; fmtmcy, tu ifrxe-vfut kpr hnqiiekl am nznx swfsg, nne c ryds, hgj s ebztota, ofr t zaovlo qtigzshc kmaqe wbav s pkbae iovf phgj mbvv khx tofher. Aof trgm weguqkmwgobufe iwkh ulbwomu aof abqiuw sw, ipby chcsjwgts ph rof zpgkf; mulS uoa wuoz. Uwn tal gal fniegnc yvv agv fhsvn ff vgflr, uojabpszlkvrka, hl cwxs ij iy avwm and cgex vvl ukkf zyliklg ab mue Julkpr vyLtwatof. Fome, bxocdr, muez drywuom hgisa ff lpznsk jhftesp khlgchlk zg ihay, agk hgkxys ph lspsu, lueq nzveg hbv ghze xjidg; ouw Ogcgoxj. Szk qe a ephlzx jhjne djs ttt kma lfwg ac lvx gacne. Kpr Pcch uxdl fv pzm, tur tsebw ng skv ose zzq tizdxug, wlvrpu vhyus daugcwaxj gz ba. Rnw avw htolf yac qt zbrnqy, ied mos uzhght wpyp hoxdcpsx cwdl ww lbusf; ogq np xecuss pgk elzmew bdgb mue ucbvg hotz omzxqh lbzzqy ww ghsr gf hs sjnvot, cy hl tgmnrlh-ocjb. Tad pwr wgoagcg iku*msob ko nz. 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Trgb P mudp apv mtu kzc B jat, cnn yvhmgcg aak umbav oy tm bcnenfa; axf ghbj lthb Z wtz gwsdvnh yhovvlk gfkyps dty kgwmiihy hg ax, br xjedjsy B iggsl xabu hzs fnsugri qjlk gdx.Djs ttt davsvd nwcf ax, nne je cowsxj szk ariw, 'Pt A rbq npv focf ahnkgakkke apve mvc eivu, I xquvf gohc ltlm khta kzwvu tiqu cgsrxyl.'Ercu mnae P jvctts sbqvovu axf gvkxgimcc, agk kzsg ghf oax rsyvkahllsv, vl lgap, 'Pn khhb kgieqetv rkvvlk zzma Q jhhbzv gabw ujeo vvfnkghwbszaixe moof havnf cdfcbatmw, U dqcl wv gg. Gereq jebg hv-xkuom, gfp pv khx tcjbbag bticg shkrq, mul kadl hzs kbae wpgcfkldjfvnmz fom maessq iggim vhyw fltizqzb khx dcgr murpwgr yvpvn ltvcmcallz zuapvr. T swlher wba wsvvpg zzq dwfd mocm kbyt nged ywaa gbqok uxszjpznz vtx hh ghf tiqjh, ir czujp khhb amgm crpeeof, iumoddjcb vueqzb ko t sojux fhfntotsk zrspl ezta h agigq io vho esumxw.Kpr aaum iptk sxl o tztpk ncn yh uyxgl eaikukl cf har tpr op vvlwqiuw. Nw uz vft ltodzxe io uijg hott liv ww tal awb hs tiks gqfsw.Rg vhl hmf vvv fhvh; sbw bnf gyo kb aak euklce hm vag ybrfjekf. Ouwrg vhl g uxbj ff bycf, ogq iu ks mgfatof foik talfw okr np vwy osu btdjs dhxdp dpf whbzv bhg fjpd djspk hmdkme ig avsh vyuc. Cnn js plxqh h vueqsg dag, iil cg ghf eoxvfhke zq pa vxvlsvwgtlz klv-hochajqk;kpr ox ok fom nohkksfw bf ujad ycvw. Gfp apfu ppzl gxr a ujoeuouwgkzk ttayhtj gkhnabz nrpwnn jwt. Btigpzv oy owe har wba oev cm mnwqnokx, gfp om nies fwdel tp vhog pybkxxf, ied ppzd dhvnu qud vvl kuspla kobiz fowl sahzl tbad ujad yvpvn ltvc rrm pb iixft ph.'"Kpr shty elmdew avsh gvgiv ty os. Hgj ltl vvxm tcjbbag J cryus hgjosipivwp tgjeem, ofr fbuoven om ohxkq, hvu pkvqwswrd tvrkkuom zzdvcxhdjs ctrdqf bf tal kgcw; nne K fynzvpkv fom trhzg-jctq wikcr vvl fgfrcr whoffll fum ac es, mvlm ct vgbnmn A myzzvxk ol har gmcdo. Cbkdjsyx cse P byrxl haaxf mpte kuhvgoktll rt mos fifoes qf gkzk ttayhtjdjoa B hwtltu, tahb lvx zao jan uopw O ktvccd ul. Ofr mue cnamm ahggcg aakjq, zqktbuu mdha tig tyr cm mnw yvced. Abuw cy ftbvubg oz mnwwcb otj lasl de mool vx jat, K fywbk aoe fv mocxlr tm ynr ujenggjkohfpwe hx oov ubieo oe yh vpf. Gk rvz khx pfgb vyuc yhsev aakwcb otj lasl de phg s pnedfp fyt hdh swz, P id cxyhswg, Xaj, vhkv wagqisw hw m omrvr dsauag fpt fywf dtxjuvzj th swxh; tad ujic yoz btdjs ieguw tie's ahbv. Ogq hf qnva gwhqw fv uv ig hbkkxe tp oyawszmogzz. Byeg P okyxq hjo wrch whcwd om yeek cnsk ghpue kpwttrk.'S ywse yzad byex, swlher mbp,' skkr ox. Gfp om kohr vag vyuc kn rkgrcbk, ttv ipby im os khkhcl c sdcu h zxwma jcop zc lvtg hf drkaskfgvlfkffsg, rnw hh zwl orbaixi hox gfutics vhaw hhteujeb, cg unswdvcjku hox ylmya zn mos kyr, fo ujad kh dty vumnzcnsh xck ze uq fspr yhuesp hox mdmkm ko laofr tzooi trga. Aakjq dmie llfhsggs, bpd ntonhtk,kpr kbbwdz afrmz cx ogvmbns. Kpr ox rgarmu am avwa, tad ccdo vvlf mgkpr mxkv; mul khxf pgkxq tigib jshwy, szk lzd apa zcfngf cs fcgztrk fv byeby zgfw."Djsu mnw nsitk fhb kobq tp oe, 'Cgszm zzab vfw, ephlzx zao, yhkvzqklk O zasl fvxy hzslr aokmkng?' Aakf U pvhubysv cy uin vho yof,kpr ox hwohuv vxym jcnth jp hsu ahgtwd aw de; avkwjxe, hf csugr txgjwaakj U dwllw nc? Sbw jhfp I dqzk aoe iow Z wtz ofr puau K sywuom,rg rpkkufll de. 'Mhyw,' gtvd ig, 'trch wtzz foik lxhrk hhjasfs djsrgok hl ltl ocawl, ofr tfcfpd djs dhuvqk akexw ifhby tiqu mqallz lasvg znseua; ied mosjs muov yivv tpgj sz vxvn lwous evkf vo k noyzkfczsxe, szk qe tal aarlg og kt k vose zjql, eyoll pjogphfu abgqtslgkj foie tal ujsxaetv psps-akkwe. Bvuek avag meef ks k hcbgzsuu,kpr ir zzq zque hm hzs ybuovasp o ttxtxl acau, hbv cg ghf oabdzl lrsnk uwsokj nvec, amaouvxq bz c crcwu hl kusdvr, lv hzom vt ncy xqh ixmcfybkv mdip. Ttrs lvx ooxn axf hokuo m iwnlybz gt pntft uzqb aakcnoi, ttv fowl wbsh zste a nkgrvm wxgd am byugksj, gh ghbv trqi dbrldjwud zzma pvaolb sbw rasvh kts akkensqeg pphz wmf fvty. Gkho mnwdjiuwkj fomie ppzd qhze b uhyysy lu kqcmie mool wm jimn bo uqhkiwzqgzbhdq mwi tals lc xadvte sv ouw rahl. Ied mos kvhjes yivn pl hlrcwslzgzla; rnw htlsk ghf uhyysy, mnw ilikhxy kaze oedqmo hopk, hmfoxsyr rwmm byam dok iibn uje dtsl podx oime ulsf qterjgd kyof ue ltlcjcdxx. Ltlv r fepuzh hs bjtdc ywse igyl ied tswyvm hppp trg hyxk;kpr pg zzuum fwg jcmbmey ujoe fwklz fqcmi hxhf s gmeajp sy uklxz sedjoa pnaoo byer dwdz lvnh. Cnn ch aak eatmet mocm okg mput ngzpznlqkgkho mnw evvx oy avw pbedt, vhyw kpez zqhz r mnyamfbag bpdmqawegazpvx chtwfu mbwbtdc vvlx gdauo khx codzxl. Aof trqi dbrl elmk mbpznl gwwe a vvod-pencl jobus, jeultll zn usouy orlwgt, kpr dbzz mzgbuht gr itrcd swfsg hppp hsu zhgiw; mul ye ppzd fbqe vpty vvlx zgopqvntlqy byex dwlv mue vvmyuh zikwp. Pn khhb tdsxft gtow jwt akgkzs hbwdaibe mosw, ogq ig vhyw oibjwea byekl, ok gnee bu trqi hkz swqiumkv wuqxhm, os owey lfcvo vvlx uf rvwk. Agk wx habu eqsd pcapkbk mxggitv ig avsh tqvfptets, aaum zlmuela bgh lrel kt nwfpgm ltlbgga hl ltf tzfx.' "Cq W qhajzlgvd hu, ifhby I sgamjsk mnw ebudim vt lvx ftfgp, kprdjsyx O xabvu eolfqhavnh cs djs ieguw tie htk rwgveicgd sv hv fk.Kpr P pkff bx ko mos lfxr, aof bopshmn af P arw mos xcnatbkn, kpr irsvg zbjw fom dakizw genb, bpd djs zbrnqy jfwe mokhxaee dy djs jagaz.Djsu B zgar bye uvkd, ogq cbut k dcdelmx vn namlf mdha tig svcp; hgjdjsyxahau, jvhhsr, lvx ghvpdot qhfk, egjp dokl jacernu vhkp hox hdmjswcb otj dqk uv th llhsvg; aof apvsy mnw focedxy qsax ghf uhyysy; ttvyh o akalt P bvle avws, Dni, ujad vvlkk ae umztalf eog aos dekuh aaglmcb lgjmdl byam zvgkxe aof lsxs. Mhx faa wee hm hzclr hbklcvcuxygqisw hw eawgpxk, saharr ca trg tsxyz ay jp tal gcwg, hnukl sv vhwbgojakv fom sogl. W likaee oy rqfzx'y xxhvb thdojrl ghf uhyysy, ttvznojxj ltl jvad vt em luifnd yxsy aok tliu agk bwqd, jhjne S jssw zzqerdlk vsda ww im vjwf fl oxp hocr. Hgj ltba Z wbavkhhbd uje cjcdxx.Gjsu B rgarmu og avw hkre ujebg khl tgf h aznzss dsts uqqn sv, ouwdjsu mnw erg sevhaw qeras, cnn ywaa zzma, jvhhsr lvx oisfs vkuomkvercu mnw fymv, agk gsbz. Nne vrenm, Rto, A zldvr alojr tay nglyfmosihe zg foik, ebavwf urfpte yt gpgiw. Mul nhxu W ool zotv crcftxjgkho eokflvznz ac lvx oisfs, vq, o tnxegyqeg ovwus pns igabf hoku*msodjs ctrdqf, igpkvouvbag ng axf ghrofs, 'Vp, Bnbnvl, kant ics ltcbznldjsl aoltlz? Nhta snwe uawg I nqbl mu ltlm, khta hzcn fhpwlnuh hvz

The question is which cipher method has been used and how to find the key.

It was discovered that the key was literaly "in front of your eyes". The header image consisted of mayan numbers, that translated to the sequence 10 2 14 7 19 6 18 12 7 8 17 0 19. Comparing it with the title, it was found that 10 = a, 14 = e, etc. So the whole title could be translated to 10 2 14 7 19 6 18 12 7 8 17 0 19 7 14 18 14 19 13 0 1 2 0.

The text lines were found to be a Vigenère cipher. The numbers can be translated to a Vigenère key by letting 0 = A, 1 = B, etc. You can do this using Boxentriq's letters to numbers tool, which gives you the key kcohtgsmhirathosotnabca.

Now you can decode the texts, line by line, using Boxentriq's Vigenère cipher tool. You can see the result in the screenshot below:

Here is the whole text:

King Arthur was at Caerlleon upon Usk; and one day he sat in hischamber; and with him were Owain the son of Urien, and Kynon the sonof Clydno, and Kai the son of Kyner; and Gwenhwyvar and herhandmaidens at needlework by the window. And if it should be saidthat there was a porter at Arthur's palace, there was none. GlewlwydGavaelvawr was there, acting as porter, to welcome guests andstrangers, and to receive them with honour, and to inform them of themanners and customs of the Court; and to direct those who came to theHall or to the presence-chamber, and those who came to take up their lodging.In the centre of the chamber King Arthur sat upon a seat of greenrushes, over which was spread a covering of flame-coloured satin, anda cushion of red satin was under his elbow.Then Arthur spoke, "If I thought you would not disparage me," saidhe, "I would sleep while I wait for my repast; and you can entertainone another with relating tales, and can obtain a flagon of mead andsome meat from Kai." And the King went to sleep. And Kynon the sonof Clydno asked Kai for that which Arthur had promised them. "I,too, will have the good tale which he promised to me," said Kai."Nay," answered Kynon, "fairer will it be for thee to fulfillArthur's behest, in the first place, and then we will tell thee thebest tale that we know." So Kai went to the kitchen and to the mead-cellar, and returned bearing a flagon of mead and a golden goblet,and a handful of skewers, upon which were broiled collops of meat.Then they ate the collops and began to drink the mead. "Now," saidKai, "it is time for you to give me my story." "Kynon," said Owain,"do thou pay to Kai the tale that is his due." "Truly," said Kynon,"thou are older, and art a better teller of tales, and hast seen moremarvellous things than I; do thou therefore pay Kai his tale.""Begin thyself," quoth Owain, "with the best that thou knowest." "Iwill do so," answered Kynon."I was the only son of my mother and father, and I was exceedinglyaspiring, and my daring was very great. I thought there was noenterprise in the world too mighty for me, and after I had achievedall the adventures that were in my own country, I equipped myself,and set forth to journey through deserts and distant regions. And atlength it chanced that I came to the fairest valley in the world,wherein were trees of equal growth; and a river ran through thevalley, and a path was by the side of the river. And I followed thepath until mid-day, and continued my journey along the remainder ofthe valley until the evening; and at the extremity of a plain I cameto a large and lustrous Castle, at the foot of which was a torrent.And I approached the Castle, and there I beheld two youths withyellow curling hair, each with a frontlet of gold upon his head, andclad in a garment of yellow satin, and they had gold clasps upontheir insteps. In the hand of each of them was an ivory bow, strungwith the sinews of the stag; and their arrows had shafts of the boneof the whale, and were winged with peaco*ck's feathers; the shaftsalso had golden heads. And they had daggers with blades of gold, andwith hilts of the bone of the whale. And they were shooting their daggers."And a little way from them I saw a man in the prime of life, withhis beard newly shorn, clad in a robe and a mantle of yellow satin;and round the top of his mantle was a band of gold lace. On his feetwere shoes of variegated leather, fastened by two bosses of gold.When I saw him, I went towards him and saluted him, and such was hiscourtesy that he no sooner received my greeting than he returned it.And he went with me towards the Castle. Now there were no dwellersin the Castle except those who were in one hall. And there I sawfour-and-twenty damsels, embroidering satin at a window. And this Itell thee, Kai, that the least fair of them was fairer than thefairest maid thou hast ever beheld in the Island of Britain, and theleast lovely of them was more lovely than Gwenhwyvar, the wife ofArthur, when she has appeared loveliest at the Offering, on the dayof the Nativity, or at the feast of Easter. They rose up at mycoming, and six of them took my horse, and divested me of my armour;and six others took my arms, and washed them in a vessel until theywere perfectly bright. And the third six spread cloths upon thetables and prepared meat. And the fourth six took off my soiledgarments, and placed others upon me; namely, an under-vest and adoublet of fine linen, and a robe, and a surcoat, and a mantle ofyellow satin with a broad gold band upon the mantle. And they placedcushions both beneath and around me, with coverings of red linen; andI sat down. Now the six maidens who had taken my horse, unharnessedhim, as well as if they had been the best squires in the Island ofBritain. Then, behold, they brought bowls of silver wherein waswater to wash, and towels of linen, some green and some white; and Iwashed. And in a little while the man sat down to the table. And Isat next to him, and below me sat all the maidens, except those whowaited on us. And the table was of silver, and the cloths upon thetable were of linen; and no vessel was served upon the table that wasnot either of gold or of silver, or of buffalo-horn. And our meatwas brought to us. And verily, Kai, I saw there every sort of meatand every sort of liquor that I have ever seen elsewhere; but themeat and the liquor were better served there than I have ever seenthem in any other place."Until the repast was half over, neither the man nor any one of thedamsels spoke a single word to me; but when the man perceived that itwould be more agreeable to me to converse than to eat any more, hebegan to inquire of me who I was. I said I was glad to find thatthere was some one who would discourse with me, and that it was notconsidered so great a crime at that Court for people to hold conversetogether. 'Chieftain,' said the man, 'we would have talked to theesooner, but we feared to disturb thee during thy repast; now,however, we will discourse.' Then I told the man who I was, and whatwas the cause of my journey; and said that I was seeking whether anyone was superior to me, or whether I could gain the mastery over all.The man looked upon me, and he smiled and said, 'If I did not fear todistress thee too much, I would show thee that which thou seekest.'Upon this I became anxious and sorrowful, and when the man perceivedit, he said, 'If thou wouldest rather that I should show thee thydisadvantage than thine advantage, I will do so. Sleep here to-night, and in the morning arise early, and take the road upwardsthrough the valley until thou reachest the wood through which thoucamest hither. A little way within the wood thou wilt meet with aroad branching off to the right, by which thou must proceed, untilthou comest to a large sheltered glade with a mound in the centre.And thou wilt see a black man of great stature on the top of themound. He is not smaller in size than two of the men of this world.He has but one foot; and one eye in the middle of his forehead. Andhe has a club of iron, and it is certain that there are no two men inthe world who would not find their burden in that club. And he isnot a comely man, but on the contrary he is exceedingly ill-favoured;and he is the woodward of that wood. And thou wilt see a thousandwild animals grazing around him. Inquire of him the way out of theglade, and he will reply to thee briefly, and will point out the roadby which thou shalt find that which thou art in quest of.'"And long seemed that night to me. And the next morning I arose andequipped myself, and mounted my horse, and proceeded straight throughthe valley to the wood; and I followed the cross-road which the manhad pointed out to me, till at length I arrived at the glade. Andthere was I three times more astonished at the number of wild animalsthat I beheld, than the man had said I should be. And the black manwas there, sitting upon the top of the mound. Huge of stature as theman had told me that he was, I found him to exceed by far thedescription he had given me of him. As for the iron club which theman had told me was a burden for two men, I am certain, Kai, that itwould be a heavy weight for four warriors to lift; and this was inthe black man's hand. And he only spoke to me in answer to myquestions. Then I asked him what power he held over those animals.'I will show thee, little man,' said he. And he took his club in hishand, and with it he struck a stag a great blow so that he brayedvehemently, and at his braying the animals came together, as numerousas the stars in the sky, so that it was difficult for me to find roomin the glade to stand among them. There were serpents, and dragons,and divers sorts of animals. And he looked at them, and bade them goand feed; and they bowed their heads, and did him homage as vassals to their lord."Then the black man said to me, 'Seest thou now, little man, whatpower I hold over these animals?' Then I inquired of him the way,and he became very rough in his manner to me; however, he asked mewhither I would go? And when I told him who I was and what I sought,he directed me. 'Take,' said he, 'that path that leads towards thehead of the glade, and ascend the wooded steep until thou comest toits summit; and there thou wilt find an open space like to a largevalley, and in the midst of it a tall tree, whose branches aregreener than the greenest pine-trees. Under this tree is a fountain,and by the side of the fountain a marble slab, and on the marble slaba silver bowl, attached by a chain of silver, so that it may not becarried away. Take the bowl and throw a bowlful of water upon theslab, and thou wilt hear a mighty peal of thunder, so that thou wiltthink that heaven and earth are trembling with its fury. With thethunder there will come a shower so severe that it will be scarcepossible for thee to endure it and live. And the shower will be ofhailstones; and after the shower, the weather will become fair, butevery leaf that was upon the tree will have been carried away by theshower. Then a flight of birds will come and alight upon the tree;and in thine own country thou didst never hear a strain so sweet asthat which they will sing. And at the moment thou art most delightedwith the song of the birds, thou wilt hear a murmuring andcomplaining coming towards thee along the valley. And thou wilt seea knight upon a coal-black horse, clothed in black velvet, and with apennon of black linen upon his lance; and he will ride unto thee toencounter thee with the utmost speed. If thou fleest from him hewill overtake thee, and if thou abidest there, as sure as thou art amounted knight, he will leave thee on foot. And if thou dost notfind trouble in that adventure, thou needest not seek it during therest of thy life.' "So I journeyed on, until I reached the summit of the steep, andthere I found everything as the black man had described it to me.And I went up to the tree, and beneath it I saw the fountain, and byits side the marble slab, and the silver bowl fastened by the chain.Then I took the bowl, and cast a bowlful of water upon the slab; andthereupon, behold, the thunder came, much more violent than the blackman had led me to expect; and after the thunder came the shower; andof a truth I tell thee, Kai, that there is neither man nor beast thatcan endure that shower and live. For not one of those hailstoneswould be stopped, either by the flesh or by the skin, until it hadreached the bone. I turned my horse's flank towards the shower, andplaced the beak of my shield over his head and neck, while I held theupper part of it over my own head. And thus I withstood the shower.When I looked on the tree there was not a single leaf upon it, andthen the sky became clear, and with that, behold the birds lightedupon the tree, and sang. And truly, Kai, I never heard any melodyequal to that, either before or since. And when I was most charmedwith listening to the birds, lo, a murmuring voice was heard throughthe valley, approaching me and saying, 'Oh, Knight, what has broughtthee hither? What evil have I done to thee, that thou shouldst act

This text is from Thomas Bulfinch's Mythology, a classic work based on the Mabinogion tales about King Arthur and the knights of the round table, and their hunt for the holy grail. This is the original text.

Using this text, you can now decode the book cipher using Boxentriq's Book Cipher tool:

What confused many solvers a bit were that the text containted double spaces in some places. It was easy to miss the double spaces if you copy-pasted the text from the subreddit, which resulted in getting some characters wrong from the book cipher. Some therefore believed that full stops (.) should be filtered out, which you shouldn't do.

A phone number!

The Phone Call

This phone number, 2143909608, is no longer working, but here is a recording of the message you would get:

Here is a transcript of the message:

Very good. You have done well. There are three prime numbers associated with the original final.jpg image. 3301 is one of them. You will have to find the other two. Multiply all three of these numbers together and add a .com to find the next step. Good luck. Goodbye.

Looking at the image posted on 4chan, it had no obvious prime numbers, but the size is 509 x 503 pixels. It happens that both 509 and 503 are prime numbers. Therefore the total number is 509 x 503 x 3301 = 845145127.

The website 845145127.com is no longer available, but it showed an image of a cicada and a countdown:

The Countdown

Applying OutGuess on the image revealed a text:

-----BEGIN PGP SIGNED MESSAGE-----Hash: SHA1You have done well to come this far.Patience is a virtue.Check back at 17:00 on Monday, 9 January 2012 UTC.3301-----BEGIN PGP SIGNATURE-----Version: GnuPG v1.4.11 (GNU/Linux)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zn1y-----END PGP SIGNATURE-----

Time went by, and the solvers waited with greatest anticipation, but still they were a bit shocked at what came next.

Across the Globe

Suddenly the message hidden in the image changed. It now contained what looked like coordinates, spread across the globe:

52.216802, 21.01833448.85057059876962, 2.40689232945442248.85030144151387,2.40753874182701147.664196, -122.31330147.637520, -122.34627747.622993, -122.31257637.5196666666667, 126.99533.966808, -117.65048829.909098706850486 -89.9931281805038425.684702, -80.44128921.584069, -158.104211- -33.90281, 151.1842136.0665472222222, -94.172641666666737.577070, 126.813122

The location were spread out over the world in California, Australia, Hawaii, South Korea, Poland, and other places. Visiting these exact locations there were real posters with an image of a cicada and a QR-code:

Obviously Cicada 3301 were a resourcesful organization, capable of placing posters around the world. Either they had members worldwide, or they did a lot of travelling to spread out these posters. This puzzle was no longer only an online thing.

Puzzlers collaborated to visit the locations and take photos. They found there were two variants of posters, containing QR codes. They contained new book ciphers, as well as a warning not to share too much.

First message:

-----BEGIN PGP SIGNED MESSAGE-----Hash: SHA1 In twenty-nine volumes, knowledge was once contained.How many lines of the code remained when the Mabinogion paused?Go that far in from the beginning and find my first name. 1:296:46the product of the first two primes2:3714:4117:327:40the first prime2:331:17:4517:2921:3112:17the product of the first two primes22:4215:1824:3327:4612:2925:667:47 You've shared too much to this point. We want the best, not the followers. Thus, the first few there will receivethe prize. Good luck. 3301-----BEGIN PGP SIGNATURE-----Version: GnuPG v1.4.11 (GNU/Linux) iQIcBAEBAgAGBQJPB1luAAoJEBgfAeV6NQkP9oAP+gLu+FsRDf3aRcJtBkCOU2MXr/dagOTvCKWtuV+fedy0enWUZ+CbUjXOr98m9eq2z4iEGqKd3/MBXa+DM9f6YGUEjPum4wHtQDSJlZMazuYqJOVZGw5XmF25+9mRM6fe3H9RCiNDZpuXl3MzwdivYhcGB5hW14PcdHHteQf3eAUz+p+s06RDs+q1sNGa/rMQIx9QRe71EJwLMMkMfs81kfJCtCt21+8ud0Xup4tjUBwul7QCcH9bqKG7cnR1XWsDgdFP6a4x9Jl2/IUvp1cfeT7BYLS9W3lCM8thMemJr+ztQPZrpDlaLIitAT2L0B3f/k4co89v5X2I/toY8Z3Cdvoihk0AdWzMy/XLDgkPnpEef/aFmnls53mqqe9xKAUQPMrI73hiJ+5UZWuJdzCpvt+FBjfQk15EJoUUW16K2+mBA1cSd+HJlnkslu*tsjkq0E36XKChP+Cvbu/p6DLUMM2Xl+n3iospCkkHR9QDcHzE4Rxg9A435yHqqJ/sL2MXG/CY8X4ec6U0/+UCIF9spuv8Y7w66D05pI2u9M/081L7Br0i0Mpdf9fDblO/6GksskccaPkMQ3MRtsL+p9o6Dnbir6Z2wH2Kw1Bf0Gfx4VcpHBikoWJ5blCc6tfvT+qXjVOZjWAL7DvReavSEmW1/fubNC3RWcjeI4QET2oKmV2NK=LWeJ-----END PGP SIGNATURE-----

Second message:

-----BEGIN PGP SIGNED MESSAGE-----Hash: SHA1 A poem of fading death, named for a kingMeant to be read only once and vanishAlas, it could not remain unseen. 1:5152:24the product of the first two primes14:137:3612:107:1624:3271:2210:713:2812:786:1793:14the product of the first two primes16:796:419:1347:271:2275:977:4 You've shared too much to this point. We want the best, not the followers. Thus, the first few there will receivethe prize. Good luck. 3301-----BEGIN PGP SIGNATURE-----Version: GnuPG v1.4.11 (GNU/Linux) iQIcBAEBAgAGBQJPB/nmAAoJEBgfAeV6NQkPEnEQAKl5qtb3ZE5vs+c08KuzAi4atQEE71fvb65KQcX+PP5nHKGoLd0sQrZJw1c4VpMEgg9V27LSFQQ+3jSSyan7aIIgSDqhmuAcliKwf5ELvHM3TQdyNb/OnL3R6UvavhfqdQwBXCDC9F0lwrPBu52MJqkAns93Q3zxec7kTrwKE6Gs3TDzjlu39YklwqzYcUSEusVzD07OVzhIEimsOVY+mW/CX87vgXSlkQ69uN1XAZYp2ps8zl4LxoaBl5aVtIOA+T8ap439tTBToov19nOerusB6VHS192m5NotfQLnuVT4EITfloTWYD6X7RfqspGt1ftb1q6Ub8Wt6qCIo6eqb9xmq2uVzbRWu05b0izAXkHuqkHWV3vwuSfK7cZQryYA7pUnakhlpCHo3sjIkh1FPfDcxRjWfnou7TevkmDqkfSxwHwP5IKo3r5KB87c7i0/tOPuQTqWRwCwcWOWMNOS7ivYKQkoEYNmqD2Yz3Esymjt46M3rAuazxk/gGYUmgHImgcu1zzK7Aq/IozXI7EFdNdu3EoRJ/UL9Y0l0/PJOG5urdeeTyE0b8bwgfC2Nk/c8ebaTkFbOnzXdAvKHB03KEeUPtM6d6DngL/LnUPFhmSW7K0REMKv62h9KyP/sw5QHTNh7Pz+C63OO3BsFw+ZBdXLhGqP6XptyZBsKvz2TLoX=aXFt-----END PGP SIGNATURE-----

Later, the website changed again, and contained a list of numbers. Someone found that if you typed in http://thewebsite/thenumber.jpg, it would also show you the poster (without any need for you to physically travel there).

-----BEGIN PGP SIGNED MESSAGE-----Hash: SHA1 162667212858414974253863598852142735876873892385935691396441316744223127427566844663644169769482889296759263963846244281-----BEGIN PGP SIGNATURE-----Version: GnuPG v1.4.11 (GNU/Linux) iQIcBAEBAgAGBQJPDRkvAAoJEBgfAeV6NQkPVuMP/3ZyAgwsko/B2T9Ew1yqAKVyK9//wIWCRvMyZ4k79ApqvOJAlezgHTsAM8XG/I71bAG+2wMOXNJfTj/SFONEEbS5BOp9UP7LHn1j3NKoESrDzsKd+u3oHoNnhs628aLrc8uDqbn/6DNUnObu5Tn3unu0zZ3NjSs/A5QQX8O56RsK81eSJ2fifbr4NYfHBeUTeVe17nsr48WQI7qc9UVWlPsM91FWsvhX+WohX8DyFWJmtz0lLvmh3jN+oE8WFPTVbcVCM+eiDt0TqkUNlmq/fxbdX2Sbs8zMxDXNQWrw58TcSC6oLfXSXZnjh8uTMwrQ0tNdRXHDndgPiurXz62XjVjf4AhSXBoXF9CHTOyGGEqvfNvFMKyz968iMZDXDNBrM8pkxx1xBHhAnoEznVpeMhII+IfBTnV8x9lSNgFhmham5eEZlWvqRidqes8EAriqGA6uZokCq7X1IeMHo52ACWmP2bJsCV5wZDc52c3JnwKe+cAcbsA4OWCNEH29lAsgFw5079BP8lkpY3AH2+8kqs0XQvqsaMuUq5ZHEaZMgdD0VKYlRrKdhOiDjtJVxoXk1b7YBOV8dZZBXJbEIbTvaof4yhgUObovx/VFGmsenp+j3nBCxgEO22SgNW3B3pN0yuIMCqccWEZ1nME/QOwLa85nHOmElIXvK13Q9m545RtP=Q1Fy-----END PGP SIGNATURE-----

The second book cipher was broken first. It was found that the book used was Agrippa (A Book of the Dead) by William Gibson. The poem, which came on a 3.5 inch disk with the book, was programmed to encrypt itself after a single use. The decrypted text was:

sq6wmgv2zcsrix6t.onion

Later, also the first book was found. It was Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 3 "Chitral" to "Cincinnati".

Into The Dark

If you are familiar with the dark web, you will recognize that this is an address on the TOR network. The dark web is a kind of "internet underground", which requires specific software and configurations to access. Identities and locations stay anonymous, and cannot be tracked. This is where the puzzle went "off the grid".

These were the instruction that met the people arriving here:

Congratulations!Please create a new email address with a public, free web-based service. Once you've never used before, and enter it below. We recommend you do this while still using tor, for anonymity.We will email you a number within the next few days (in the order in which you arrived at this page). Once you've recieved it, come back to this page and append a slash and then the number you recieved to this url. (For example, if you recieved "3894894230934209", then you would go to "[http:// http://sq6wmgv2zcsrix6t.onion/3894894230934209]")3301

What happened after isn't possible to verify, but some emails have leaked. Here is what happened next.

The RSA puzzle

The first people who provided an email address on the dark web site were sent an email with another test:

-----BEGIN PGP SIGNED MESSAGE-----Hash: SHA1This message will only be displayed once.Here is a message that has been encrypted with RSA (the Crypt::RSA Perl module available in CPAN) :- -----BEGIN COMPRESSED RSA ENCRYPTED MESSAGE-----Version: 1.99Scheme: Crypt::RSA::ES::OAEPeJwBzQAy/zEwADE4OABDeXBoZXJ0ZXh0B4KeBtKjJ7hGKC7/zqyzxUoFDTzRuU4+TLFUrw9qDGjkYI3fjyMn3G/w9WcfkZMGHdGRicbpTsDO3/oqmVtZpmIDY2HPOeWIZChuLfMDwT3FTUkDjQpsq390OJ90pArd1JRxdIZtnCvnVy/vg+1MjAFH3ta+CuAwHsIY/3lGOKTin1+5M30BKh7NOQMmBcJ8/RuLTfXMGQT01QVMeAGq6vORk3iw39KOLRU3Lcn1804G1/zd2mdFWvEMaTbu/F+7=0KfiT9PUe6QkwJXoM36Ukw==- -----END COMPRESSED RSA ENCRYPTED MESSAGE-----Here is the public key used to encrypt it. Note that it has a low bit modulus and is therefore breakable:$VAR1 = bless( { 'e' => 65537, 'n' => '7467492769579356967270197440403790283193525917787433197231759008957255433116469460882489015469125000179524189783', 'Version' => '1.99', 'Identity' => }, 'Crypt::RSA::Key::Public' );The encrypted message is a number. Break the decryption key, then come back to this same URL and enter the decrypted message to continue. Each person who has come this far has received a unique message encrypted with a unique key. You are not to collaborate. Sharing your message or key will result in not receiving the next step.There is a second chance to get your own RSA message and key. Follow the "Numbers dot TK" hint to find it.There are many fake messages out there. Only messages signed with public key ID 7A35090F are valid. Good luck.3301 -----BEGIN PGP SIGNATURE-----Version: GnuPG v1.4.11 (GNU/Linux)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S6GG-----END PGP SIGNATURE-----

To solve this, you need to break an RSA key. You will need to factorize the big number (with 112 digits), n, into two prime numbers. This is far from easy.

Factoring big numbers requires advanced mathematics. Luckily, there are publicly available open source projects that can be used:

• MSieve
• CADO-NFS

Both options make use of the Number Field Sieve (NFS) algorithm. On a modern computer, you should be able to factorize the number n in less than an hour. You will get these prime factors:

p = 94424081139901371883469166542407095517576260048697655243q = 79084622052242264844238683495727691663247340251867615781

Now you can continue the calculations to get the secret exponent, d, by using Boxentriq's big number calculator and Boxentriq's modular multiplicative inverse calculator.

phi = (p-1)(q-1) = 7467492769579356967270197440403790283193525917787433197058250305765111796388761610844354228288301399878958918760d = 65537-1 (mod phi) = 6095845029215954627034931303907142169470229688202235204684671759588136716587612454316830292189081535500929599993

Now that you have the secret key, d, you can use the Crypt::RSA Perl module to decrypt the message in the email.

The MIDI puzzle

The next puzzle received by email was this text, and a piece of music (Cicada 3301 MIDI file).

-----BEGIN PGP SIGNED MESSAGE-----Hash: SHA1This song is your own pathAnother stop on the road toward enlightenmentFollow it, and share not Let the Chorus be your guide to the depths :Let the Priests of the Raven of dawn, no longer in deadly black, with hoarse note curse the sons of joy. Nor his accepted brethren, whom, tyrant, he calls free lay the bound or build the roof. Nor pale religious letchery call that virginity, that wishes but acts not. For every thing that lives is Holy.Good luck.3301- -----BEGIN PGP MESSAGE-----Version: GnuPG v1.4.11 (GNU/Linux)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*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=yk7h- -----END PGP MESSAGE----------BEGIN PGP SIGNATURE-----Version: GnuPG v1.4.11 (GNU/Linux)iQIcBAEBAgAGBQJPGOY0AAoJEBgfAeV6NQkP7KQQAJ7qfuZgtthyD6hXiPvrYXClDnbj4viLPeiwVC/dYHn76yixqImr4+gzWEGzr+MrNpaPRBtCxu7kmBtwuyNHoqlzKINmTLuwjpLkU/VBi02b17Z5UbCguEn8ZZDq8HFJgl3I8teQOBpmNorfsR0+CmjMbtuLdiZkLS0f9LS4mCivnlJmr6ULIwiAh7KaCQbj3s908raMQL+uIg6GXort1ilosppcEaykOHUmz+cxG2xpOD1KVt/IqSawimB3xfveCcLyRRfRQp4ACyL+eBiTzuT9IJ9NmCrE3OcFtzJa0S2JjlOI5x1h70GEl1D/rpTu3zOR6I3YF68RufIxtnfpDsx36OORSR0kWVO1fVAotL3QfPxq6cjsy5Q+Gm5QeAvI+e5k2lGIL83d3JS23s0IjopSgJWHwwIF5q9uHrg8oPIJkYkc1Dxzrvgc5DcHsYo+KQxWYsPhjh7nQp8hl0KpK8Q/I8yFg3afBfH1ci15HifKVwAJGtrki3+NkPDw7IuwFDtW6NCd4SJ6XQv9fw7NyYQk/qxbiOrz4yD7MOY9tKapdDMc5B4jIBaGULoKiMqk4KBHc05Z8I4yqaCfWI0BfijJVvKgLCx8mLillkKKH8A+f4CG191MKd0LwfrWNDCC62e5vWRaulV0coR2DTrCFFDAFZL1IQd0u3QtmG5aRBhi=kTmp-----END PGP SIGNATURE-----

The MIDI file is a form of musical cryptogram. Analyzing the MIDI file shows that it has two tracks (providing two different messages). Each message has fewer than 26 combinations of pitch and tone length, which is a hint that each combination of pitch and tone length could represent one letter.

This can be solved in different ways. This is a short Python program that converts a track from the MIDI file into a text cryptogram. It uses the open source MIDI parser mido, which you will need to install before running the program.

import midodef getNotes(filename, track): result = '' for msg in mido.MidiFile(filename).tracks[track]: if msg.type == 'note_off': result += f'{msg.note} {msg.time}\r\n' return resultdef notesToSingleLetters(msg): result = '' letters = list('abcdefghijklmnopqrstuvwxyz') dict = {} for line in msg.splitlines(): if line in dict: result += dict[line] else: letter = letters.pop(0) result += letter dict[line] = letter return resultprint(notesToSingleLetters(getNotes('cicada-3301-2012-midi-song.midi', 1)))

You can then break this cryptogram using Boxentriq's cryptogram tool:

The End

What happened to the people who completed the MIDI puzzle? This is still unknown, apart from some leaked emails and testimonials that cannot be verified.

After a month, the image on the subreddit changed:

Then nothing was heard from Cicada until January 2013, when their next puzzle started.

Learn more about the mysteries at the Uncovering Cicada fandom.

See also: Code-Breaking overview | Quantum computing | Zodiac ciphers