Cicada 3301 First Puzzle Walkthrough

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

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:

Cicada 3301 invitation (original file)
Cicada 3301 original 4chan invitation

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:

Cicada Invitation Caesar Text
Text extracted from the 4chan invitation

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:

Cicada Invitation Caesar Decoded
Decoded Caesar Cipher text

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: http://i.imgur.com/m9sYK.jpg. This image however looks like a dead end:

Cicada Invitation Outguess Decoy
Cicada 3301 decoy image

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 http://www.reddit.com/r/a2e7j6ic78h0j/

1:20
2:3
3:5
4:20
5:5
6:53
7:1
8:8
9:2
10:4
11:8
12:4
13:13
14:4
15:8
16:4
17:5
18:14
19:7
20:31
21:12
22:36
23:2
24:3
25:5
26:65
27:5
28:1
29:2
30:18
31:32
32:10
33:3
34:25
35:10
36:7
37:20
38:10
39:32
40:4
41:40
42:11
43:9
44:13
45:6
46:3
47:5
48:43
49:17
50:13
51:4
52:2
53:18
54:4
55:6
56:4
57:24
58:64
59:5
60:37
61:60
62:12
63:6
64:8
65:5
66:18
67:45
68:10
69:2
70:17
71:9
72:20
73:2
74:34
75:13
76:21


Good 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.

Cicada Subreddit Header Mayan Numbers
Cicada 3301 Subreddit Header

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

Cicada 3301 Reddit Welcome
Cicada 3301 Subreddit Welcome Image (original)

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:

Cicada 3301 Reddit Problems
Cicada 3301 Subreddit Problems Image (original)

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: SHA1

The 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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=SqLP
-----END PGP SIGNATURE-----

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

Ukbn Txltbz nal hh Uoxelmgox wdvg Akw; hvu ogl rsm ar sbv ix jwz
mjotukj; mul nimo vaa prrf Qwkkb aak kau ww Ukpsf, ogq Kzpox vvl luf
yh Qsrjfa, hvu Ktp hzs lbn ph Kipsy; ttv Sdmehpfjsf tad igr
rcbkfgaplvj am uswrerwptk la hox cazkwn. Agk wx wm fhpwln ds ztov
djoa mnwdl ers t wcjhxe au Crdjiy'l vsxhkv, talfw ktf nppe. Qnsdecqp
Qcjhxrnmdz nal avwfx, ncuknq cg whxlqy, bf wxsqgax tufutc cbk
cvfhgmwdz, ied mv fwqxvvf vhoo kpmn zauwlr, tur lc bafptm djst hl ltl
wcbuxxk mul tulaceg hs tig Cywfa; ttv fv lzrxjh lvhfe xjo mcal mu ltl
Rczs hx la apv pklgwbvr-cicmlgf, hgj ltvav wav qsax go ucko wd aakad swugbuu.
Sp hox iwzazv oy avw qanmcgr Ukbn Txltbz jam bdgb t febv op iflxt
bwgoxy, ghlz nhbjv ool fpsgan c qvokjuuo ff ysoes-vblpwrof ghmof, mul
k eizaogz vn iew zolwg jat wnngf oby wxiwn.
Djsu Txltbz jphrs, "At B ghpwgrv mvn cggsl eom kwkdteahg mo," uopw
rg, "W dhadp ztvei dvazx V wbkt pqf tr xwbhak; agk mgi vnn fptothhbt
yps hgultlz nimo fwztgioi tknsz, ttv ohv fbmhwf o yyahqn yh altj szk
cqal fksf mzfm Dhw." Sbw ghf Mixi klgz la ztvei. Hbv Yraoo vho ucu
yh 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 tnyfjnl
Kthonx'k nlpvsm, pb lvx sisut znojx, gfp apvn pl kaze gemn trgs aak
lgga 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," ccwk
Ucw, "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 thxw
wcfcxrdaba khbuuk hann J; fo djcb mnwdlnfrx woq Ytv hju tkns."
"Lgupg zzkzmcf," jbclv Hjajp, "wsvv aak tqzb khta hzcn xnpyecv." "W
gkzs wu ka," hvjwxysv Yraoo.
"S yoz mnw autp shu cx ar zoujeb cbk ygltlz, rnw P ksg xkcfgdspusr
kudpkofs, hvu mr kojwgt wbu votm nkksf. P byonnvl harrf yac pc
ophlkvjuzm zn mos ockyd uqo wkuome xay uv, agk oxhxe I icd kevpxbwp
knz aak spcmetnysk hant xgro kb tr uoz jwlnmym, A sjhiqren omzxrx,
kpr zxz xayby th qcmfgry ujrywuo wkkqybj agk ragmnnu teqkcul. Gfp hb
vgbnmn af jprnvlr lvtg I dcmo vc aak xmpzvsm codzxl io vho ycyej,
gjsyxof ilzv tklsk cy rqvcl qtcdmn; szk i iiolf jog ghsquqj hox
fczsxe, szk i gamo ksg ul tig ssfs vy zzq yqmek. Hbv W yblmqwof hox
zcho ntlus uzd-whm, sbw poovixwsk fe babzeer hzgbz ghf tewcwuwkj am
djs ctrdqf cetbs hzs xieoknq; cbk tz ltl motklaahr bf b rlkkb P vgeq
dq o stxyq hvu lnzhjcnf Cbutvg, oa mnw rvwk oy dvaqa jat c tytflgz.
Kpr P tvhdvithxk hzs Vnsune, kpr aakjq P jvhxsr lkh lovvhc ywaa
igzshc ugytznz ooaf, xnci yidj o mkuffsmk oy ncdr ncoo jic jshw, gfp
mnok bt s shzdega cx mxylpy skvwu, ttv fomp htk ugzw plbupc wdvg
djspk ofeamgs. Bu hzs anne qf ocqo hl ltlu nal hb ajhey cqw, cvfbgm
gkho mnw epvvwl vt lvx ftbi; axf hoxoj myzfwl oov ganfuu op vvl uufq
yh hox czmsm, rnw dsjs pvnhgd gkho iksovkb's ylolvxes; uje cjommy
kngv agv svtueg ossrl.  Nne vhoa vhw jssnmis pphz pendfu op icsw, gfp
gkho 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, wsvv
rkg 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 tlxz
ggfl lngqz ww vtywwutgee nekvvlk, lseameew im lkh ootuec qt nhrv.
Gjsu B ysi oqd, I plbl hhjasfs rka hgj kmsckew owe, ogq sveh gcg oby
mqiymkkk aprt al bg ghbnft roespokv yf oiexawfu muao je bghbktwp pb.
Kpr ox cwza ezta ts lcpnreu trg Qhlzdq. Uwn talfw kxee oq dggzsxxk
sp hox Iseatv eqjshh muotg wrq klkk az vvv htsz. Sbw ghfte S uod
pqiy-ttv-fdmetr koegxys, fobbqwkxxazn artbu ol o pvneqw.  Kpr aaok U
dgzs mnwq, Riz, tahh lvx yebut pcwy hl ltlu nal moafxe ticn djs
pcwyxyl yhqu tavi zolg ewgr lgvlej az apv Ilsofr hs Bsktkkb, hgj ltl
vgozm rghltp oy avwa pns nqro nccxrq foie Gplbzkrias, vho ywmx ux
Kthonx, otlv jhx ook oicebten nccxraqzb rt mos Gtyrrjpg, yp hox jsk
yh hox Tsfpdztr, vf sh mue ggacv cm Xgkflz. Khxf fggx hp bv mi
mqapgm, 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 aakq
ggfl ikjrlkklr ifauag. Aof trg hobxv epf jpklov qebtiu uzqb aak
dcpsxy szk xieihfwr frau.  Cnn vvl yumdap jiq acgy hsf na sykzlw
qcftxtle, hvu pehqwr hghfts ercu fk; fmtmcy, tu ifrxe-vfut kpr h
nqiiekl am nznx swfsg, nne c ryds, hgj s ebztota, ofr t zaovlo qt
igzshc kmaqe wbav s pkbae iovf phgj mbvv khx tofher. Aof trgm weguqk
mwgobufe iwkh ulbwomu aof abqiuw sw, ipby chcsjwgts ph rof zpgkf; mul
S uoa wuoz.  Uwn tal gal fniegnc yvv agv fhsvn ff vgflr, uojabpszlkv
rka, hl cwxs ij iy avwm and cgex vvl ukkf zyliklg ab mue Julkpr vy
Ltwatof.  Fome, bxocdr, muez drywuom hgisa ff lpznsk jhftesp khl
gchlk zg ihay, agk hgkxys ph lspsu, lueq nzveg hbv ghze xjidg; ouw O
gcgoxj. Szk qe a ephlzx jhjne djs ttt kma lfwg ac lvx gacne. Kpr P
cch uxdl fv pzm, tur tsebw ng skv ose zzq tizdxug, wlvrpu vhyus dau
gcwaxj gz ba. Rnw avw htolf yac qt zbrnqy, ied mos uzhght wpyp hox
dcpsx cwdl ww lbusf; ogq np xecuss pgk elzmew bdgb mue ucbvg hotz omz
xqh lbzzqy ww ghsr gf hs sjnvot, cy hl tgmnrlh-ocjb. Tad pwr wgoa
gcg ikumsob ko nz. Ofr orrjny, Ucw, P lgo fomie xcsjm lbru qf wgoa
kpr lokjk zwit hm zaenbr ujad K vhok whlz jexu sdgxjhfte; lwh aak
wgoa ttv fom cijbcj kxee cgtdgf zxxnqk byekl hzog V hbxe oxsy lkwz
djst bt szf wkhxy ddovr.
"Ephpe zzq ymgala ksg anlg qvot, blbzzqy bye fhb fck nnz qno qt aak
ncazxrk ewwbe t zwfuer wptd dq al; ual iome tal asb irrdgifgr aagl ua
gqisw hw yvzv azyswouye uq mo vc jhtnqyav tahb lc xnt bpy wqfl, ak
lguhg zg uuylikl cx ax jhp K wku. W ztov U dij gehr lc yvne vhkv
djsyx cse zwde hus ovh jovnd nkgjhajel ezta ts, sbw ghbv id yoz gul
mqbzbjwdll jo zyssh t prjoe kv hotz Uabzk fhy dwciye uq hynr jhtnqyav
dqulmnwd. 'Jpzeyaoab,' lnie vho oou, 'pk oabtu htcs loexee vo djsl
cqcuxx, tga ev fxhfwr mb djutetp aakw pbzznz avq fxcatv; nyy,
rqklokj, il ezle kwkqhhrtg.' Trgb P mudp apv mtu kzc B jat, cnn yvhm
gcg aak umbav oy tm bcnenfa; axf ghbj lthb Z wtz gwsdvnh yhovvlk gfk
yps 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 ah
nkgakkke apve mvc eivu, I xquvf gohc ltlm khta kzwvu tiqu cgsrxyl.'
Ercu mnae P jvctts sbqvovu axf gvkxgimcc, agk kzsg ghf oax rsyvkahll
sv, vl lgap, 'Pn khhb kgieqetv rkvvlk zzma Q jhhbzv gabw ujeo vvf
nkghwbszaixe moof havnf cdfcbatmw, U dqcl wv gg. Gereq jebg hv-
xkuom, gfp pv khx tcjbbag bticg shkrq, mul kadl hzs kbae wpgcfkl
djfvnmz fom maessq iggim vhyw fltizqzb khx dcgr murpwgr yvpvn ltvc
mcallz zuapvr. T swlher wba wsvvpg zzq dwfd mocm kbyt nged ywaa g
bqok uxszjpznz vtx hh ghf tiqjh, ir czujp khhb amgm crpeeof, iumod
djcb 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 vvl
wqiuw. 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. Ouw
rg vhl g uxbj ff bycf, ogq iu ks mgfatof foik talfw okr np vwy osu bt
djs dhxdp dpf whbzv bhg fjpd djspk hmdkme ig avsh vyuc. Cnn js pl
xqh 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 ujoeuouw
gkzk ttayhtj gkhnabz nrpwnn jwt. Btigpzv oy owe har wba oev cm mnw
qnokx, gfp om nies fwdel tp vhog pybkxxf, ied ppzd dhvnu qud vvl kusp
la kobiz fowl sahzl tbad ujad yvpvn ltvc rrm pb iixft ph.'
"Kpr shty elmdew avsh gvgiv ty os. Hgj ltl vvxm tcjbbag J cryus hgj
osipivwp tgjeem, ofr fbuoven om ohxkq, hvu pkvqwswrd tvrkkuom zzdvcxh
djs ctrdqf bf tal kgcw; nne K fynzvpkv fom trhzg-jctq wikcr vvl fgf
rcr whoffll fum ac es, mvlm ct vgbnmn A myzzvxk ol har gmcdo. Cbk
djsyx cse P byrxl haaxf mpte kuhvgoktll rt mos fifoes qf gkzk ttayhtj
djoa B hwtltu, tahb lvx zao jan uopw O ktvccd ul. Ofr mue cnamm ahg
gcg aakjq, zqktbuu mdha tig tyr cm mnw yvced. Abuw cy ftbvubg oz mnw
wcb otj lasl de mool vx jat, K fywbk aoe fv mocxlr tm ynr uje
nggjkohfpwe hx oov ubieo oe yh vpf. Gk rvz khx pfgb vyuc yhsev aak
wcb otj lasl de phg s pnedfp fyt hdh swz, P id cxyhswg, Xaj, vhkv wa
gqisw hw m omrvr dsauag fpt fywf dtxjuvzj th swxh; tad ujic yoz bt
djs ieguw tie's ahbv. Ogq hf qnva gwhqw fv uv ig hbkkxe tp oy
awszmogzz. 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 rkg
rcbk, ttv ipby im os khkhcl c sdcu h zxwma jcop zc lvtg hf drkask
fgvlfkffsg, rnw hh zwl orbaixi hox gfutics vhaw hhteujeb, cg unswdvcj
ku hox ylmya zn mos kyr, fo ujad kh dty vumnzcnsh xck ze uq fspr yhue
sp hox mdmkm ko laofr tzooi trga. Aakjq dmie llfhsggs, bpd ntonhtk,
kpr kbbwdz afrmz cx ogvmbns. Kpr ox rgarmu am avwa, tad ccdo vvlf mg
kpr 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, yhkv
zqklk 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 tx
gjwaakj 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 djs
rgok hl ltl ocawl, ofr tfcfpd djs dhuvqk akexw ifhby tiqu mqallz la
svg znseua; ied mosjs muov yivv tpgj sz vxvn lwous evkf vo k noyzk
fczsxe, szk qe tal aarlg og kt k vose zjql, eyoll pjogphfu abg
qtslgkj 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 lrsn
k uwsokj nvec, amaouvxq bz c crcwu hl kusdvr, lv hzom vt ncy xqh ix
mcfybkv mdip. Ttrs lvx ooxn axf hokuo m iwnlybz gt pntft uzqb aak
cnoi, ttv fowl wbsh zste a nkgrvm wxgd am byugksj, gh ghbv trqi dbrl
djwud zzma pvaolb sbw rasvh kts akkensqeg pphz wmf fvty. Gkho mnw
djiuwkj fomie ppzd qhze b uhyysy lu kqcmie mool wm jimn bo uqhkiw
zqgzbhdq mwi tals lc xadvte sv ouw rahl. Ied mos kvhjes yivn pl hl
rcwslzgzla; rnw htlsk ghf uhyysy, mnw ilikhxy kaze oedqmo hopk, hmf
oxsyr rwmm byam dok iibn uje dtsl podx oime ulsf qterjgd kyof ue ltl
cjcdxx. 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 se
djoa pnaoo byer dwdz lvnh. Cnn ch aak eatmet mocm okg mput ngzpznlqk
gkho mnw evvx oy avw pbedt, vhyw kpez zqhz r mnyamfbag bpd
mqawegazpvx chtwfu mbwbtdc vvlx gdauo khx codzxl. Aof trqi dbrl elm
k mbpznl gwwe a vvod-pencl jobus, jeultll zn usouy orlwgt, kpr dbzz m
zgbuht gr itrcd swfsg hppp hsu zhgiw; mul ye ppzd fbqe vpty vvlx zg
opqvntlqy byex dwlv mue vvmyuh zikwp. Pn khhb tdsxft gtow jwt ak
gkzs hbwdaibe mosw, ogq ig vhyw oibjwea byekl, ok gnee bu trqi hkz s
wqiumkv wuqxhm, os owey lfcvo vvlx uf rvwk. Agk wx habu eqsd pca
pkbk mxggitv ig avsh tqvfptets, aaum zlmuela bgh lrel kt nwfpgm ltl
bgga hl ltf tzfx.' 
"Cq W qhajzlgvd hu, ifhby I sgamjsk mnw ebudim vt lvx ftfgp, kpr
djsyx 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 ir
svg 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; hgj
djsyxahau, jvhhsr, lvx ghvpdot qhfk, egjp dokl jacernu vhkp hox hdmjs
wcb otj dqk uv th llhsvg; aof apvsy mnw focedxy qsax ghf uhyysy; ttv
yh o akalt P bvle avws, Dni, ujad vvlkk ae umztalf eog aos dekuh aagl
mcb lgjmdl byam zvgkxe aof lsxs. Mhx faa wee hm hzclr hbklcvcuxy
gqisw hw eawgpxk, saharr ca trg tsxyz ay jp tal gcwg, hnukl sv vhw
bgojakv fom sogl. W likaee oy rqfzx'y xxhvb thdojrl ghf uhyysy, ttv
znojxj ltl jvad vt em luifnd yxsy aok tliu agk bwqd, jhjne S jssw zzq
erdlk 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, ouw
djsu mnw erg sevhaw qeras, cnn ywaa zzma, jvhhsr lvx oisfs vkuomkv
ercu mnw fymv, agk gsbz. Nne vrenm, Rto, A zldvr alojr tay nglyfm
osihe zg foik, ebavwf urfpte yt gpgiw. Mul nhxu W ool zotv crcftxj
gkho eokflvznz ac lvx oisfs, vq, o tnxegyqeg ovwus pns igabf hokumso
djs ctrdqf, igpkvouvbag ng axf ghrofs, 'Vp, Bnbnvl, kant ics ltcbznl
djsl 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:

Decoding the Cicada 3301 Reddit Messages
Cicada 3301 Subreddit Text decoded

Here is the whole text:

King Arthur was at Caerlleon upon Usk; and one day he sat in his
chamber; and with him were Owain the son of Urien, and Kynon the son
of Clydno, and Kai the son of Kyner; and Gwenhwyvar and her
handmaidens at needlework by the window. And if it should be said
that there was a porter at Arthur's palace, there was none. Glewlwyd
Gavaelvawr was there, acting as porter, to welcome guests and
strangers, and to receive them with honour, and to inform them of the
manners and customs of the Court; and to direct those who came to the
Hall 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 green
rushes, over which was spread a covering of flame-coloured satin, and
a cushion of red satin was under his elbow.
Then Arthur spoke, "If I thought you would not disparage me," said
he, "I would sleep while I wait for my repast; and you can entertain
one another with relating tales, and can obtain a flagon of mead and
some meat from Kai." And the King went to sleep. And Kynon the son
of 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 fulfill
Arthur's behest, in the first place, and then we will tell thee the
best 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," said
Kai, "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 more
marvellous things than I; do thou therefore pay Kai his tale."
"Begin thyself," quoth Owain, "with the best that thou knowest." "I
will do so," answered Kynon.
"I was the only son of my mother and father, and I was exceedingly
aspiring, and my daring was very great. I thought there was no
enterprise in the world too mighty for me, and after I had achieved
all the adventures that were in my own country, I equipped myself,
and set forth to journey through deserts and distant regions. And at
length it chanced that I came to the fairest valley in the world,
wherein were trees of equal growth; and a river ran through the
valley, and a path was by the side of the river. And I followed the
path until mid-day, and continued my journey along the remainder of
the valley until the evening; and at the extremity of a plain I came
to a large and lustrous Castle, at the foot of which was a torrent.
And I approached the Castle, and there I beheld two youths with
yellow curling hair, each with a frontlet of gold upon his head, and
clad in a garment of yellow satin, and they had gold clasps upon
their insteps. In the hand of each of them was an ivory bow, strung
with the sinews of the stag; and their arrows had shafts of the bone
of the whale, and were winged with peacock's feathers; the shafts
also had golden heads.  And they had daggers with blades of gold, and
with 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, with
his 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 feet
were shoes of variegated leather, fastened by two bosses of gold.
When I saw him, I went towards him and saluted him, and such was his
courtesy that he no sooner received my greeting than he returned it.
And he went with me towards the Castle. Now there were no dwellers
in the Castle except those who were in one hall. And there I saw
four-and-twenty damsels, embroidering satin at a window.  And this I
tell thee, Kai, that the least fair of them was fairer than the
fairest maid thou hast ever beheld in the Island of Britain, and the
least lovely of them was more lovely than Gwenhwyvar, the wife of
Arthur, when she has appeared loveliest at the Offering, on the day
of the Nativity, or at the feast of Easter. They rose up at my
coming, 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 they
were perfectly bright. And the third six spread cloths upon the
tables and prepared meat.  And the fourth six took off my soiled
garments, and placed others upon me; namely, an under-vest and a
doublet of fine linen, and a robe, and a surcoat, and a mantle of
yellow satin with a broad gold band upon the mantle. And they placed
cushions both beneath and around me, with coverings of red linen; and
I sat down.  Now the six maidens who had taken my horse, unharnessed
him, as well as if they had been the best squires in the Island of
Britain.  Then, behold, they brought bowls of silver wherein was
water to wash, and towels of linen, some green and some white; and I
washed. And in a little while the man sat down to the table. And I
sat next to him, and below me sat all the maidens, except those who
waited on us. And the table was of silver, and the cloths upon the
table were of linen; and no vessel was served upon the table that was
not either of gold or of silver, or of buffalo-horn. And our meat
was brought to us. And verily, Kai, I saw there every sort of meat
and every sort of liquor that I have ever seen elsewhere; but the
meat and the liquor were better served there than I have ever seen
them in any other place.
"Until the repast was half over, neither the man nor any one of the
damsels spoke a single word to me; but when the man perceived that it
would be more agreeable to me to converse than to eat any more, he
began to inquire of me who I was. I said I was glad to find that
there was some one who would discourse with me, and that it was not
considered so great a crime at that Court for people to hold converse
together. 'Chieftain,' said the man, 'we would have talked to thee
sooner, but we feared to disturb thee during thy repast; now,
however, we will discourse.' Then I told the man who I was, and what
was the cause of my journey; and said that I was seeking whether any
one 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 to
distress thee too much, I would show thee that which thou seekest.'
Upon this I became anxious and sorrowful, and when the man perceived
it, he said, 'If thou wouldest rather that I should show thee thy
disadvantage than thine advantage, I will do so. Sleep here to-
night, and in the morning arise early, and take the road upwards
through the valley until thou reachest the wood through which thou
camest hither. A little way within the wood thou wilt meet with a
road branching off to the right, by which thou must proceed, until
thou 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 the
mound. 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. And
he has a club of iron, and it is certain that there are no two men in
the world who would not find their burden in that club. And he is
not 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 thousand
wild animals grazing around him. Inquire of him the way out of the
glade, and he will reply to thee briefly, and will point out the road
by which thou shalt find that which thou art in quest of.'
"And long seemed that night to me. And the next morning I arose and
equipped myself, and mounted my horse, and proceeded straight through
the valley to the wood; and I followed the cross-road which the man
had pointed out to me, till at length I arrived at the glade. And
there was I three times more astonished at the number of wild animals
that I beheld, than the man had said I should be. And the black man
was there, sitting upon the top of the mound. Huge of stature as the
man had told me that he was, I found him to exceed by far the
description he had given me of him. As for the iron club which the
man had told me was a burden for two men, I am certain, Kai, that it
would be a heavy weight for four warriors to lift; and this was in
the black man's hand. And he only spoke to me in answer to my
questions. 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 his
hand, and with it he struck a stag a great blow so that he brayed
vehemently, and at his braying the animals came together, as numerous
as the stars in the sky, so that it was difficult for me to find room
in the glade to stand among them. There were serpents, and dragons,
and divers sorts of animals. And he looked at them, and bade them go
and 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, what
power 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 me
whither 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 the
head of the glade, and ascend the wooded steep until thou comest to
its summit; and there thou wilt find an open space like to a large
valley, and in the midst of it a tall tree, whose branches are
greener 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 slab
a silver bowl, attached by a chain of silver, so that it may not be
carried away. Take the bowl and throw a bowlful of water upon the
slab, and thou wilt hear a mighty peal of thunder, so that thou wilt
think that heaven and earth are trembling with its fury. With the
thunder there will come a shower so severe that it will be scarce
possible for thee to endure it and live. And the shower will be of
hailstones; and after the shower, the weather will become fair, but
every leaf that was upon the tree will have been carried away by the
shower. 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 as
that which they will sing. And at the moment thou art most delighted
with the song of the birds, thou wilt hear a murmuring and
complaining coming towards thee along the valley. And thou wilt see
a knight upon a coal-black horse, clothed in black velvet, and with a
pennon of black linen upon his lance; and he will ride unto thee to
encounter thee with the utmost speed. If thou fleest from him he
will overtake thee, and if thou abidest there, as sure as thou art a
mounted knight, he will leave thee on foot. And if thou dost not
find trouble in that adventure, thou needest not seek it during the
rest of thy life.' 
"So I journeyed on, until I reached the summit of the steep, and
there 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 by
its 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; and
thereupon, behold, the thunder came, much more violent than the black
man had led me to expect; and after the thunder came the shower; and
of a truth I tell thee, Kai, that there is neither man nor beast that
can endure that shower and live. For not one of those hailstones
would be stopped, either by the flesh or by the skin, until it had
reached the bone. I turned my horse's flank towards the shower, and
placed the beak of my shield over his head and neck, while I held the
upper 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, and
then the sky became clear, and with that, behold the birds lighted
upon the tree, and sang. And truly, Kai, I never heard any melody
equal to that, either before or since. And when I was most charmed
with listening to the birds, lo, a murmuring voice was heard through
the valley, approaching me and saying, 'Oh, Knight, what has brought
thee 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:

Cicada Mabinogion Book Cipher Decoded
Cicada 3301 Mabinogion Book Cipher Decoded

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:

Cicada 3301 phone message at +1 2143909608:

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: SHA1

You 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, 21.018334
48.85057059876962, 2.406892329454422
48.85030144151387,2.407538741827011
47.664196,  -122.313301
47.637520, -122.346277
47.622993, -122.312576
37.5196666666667, 126.995
33.966808, -117.650488
29.909098706850486 -89.99312818050384
25.684702, -80.441289
21.584069, -158.104211
- -33.90281, 151.18421
36.0665472222222, -94.1726416666667
37.577070, 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:

Cicada 3301 QR poster (in Warsaw)
Cicada 3301 QR poster in Warsaw

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.
 
1:29
6:46
the product of the first two primes
2:37
14:41
17:3
27:40
the first prime
2:33
1:1
7:45
17:29
21:31
12:17
the product of the first two primes
22:42
15:18
24:33
27:46
12:29
25:66
7:47
 
You've shared too much to this point.  We want the best,  
not the followers.  Thus, the first few there will receive
the prize.
 
Good luck.
 
3301
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.11 (GNU/Linux)
 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=LWeJ
-----END PGP SIGNATURE-----

Second message:

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
 
A poem of fading death, named for a king
Meant to be read only once and vanish
Alas, it could not remain unseen.
 
1:5
152:24
the product of the first two primes
14:13
7:36
12:10
7:16
24:3
271:22
10:7
13:28
12:7
86:17
93:14
the product of the first two primes
16:7
96:4
19:13
47:2
71:22
75:9
77:4
 
You've shared too much to this point.  We want the best,  
not the followers.  Thus, the first few there will receive
the prize.
 
Good luck.
 
3301
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.11 (GNU/Linux)
 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=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
 
162667212858
414974253863
598852142735
876873892385
935691396441
316744223127
427566844663
644169769482
889296759263
963846244281
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.11 (GNU/Linux)
 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=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: SHA1


This 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: 1.99
Scheme: Crypt::RSA::ES::OAEP

eJwBzQAy/zEwADE4OABDeXBoZXJ0ZXh0B4KeBtKjJ7hGKC7/zqyzxUoFDTzRuU4+TLFUrw9qDGjk
YI3fjyMn3G/w9WcfkZMGHdGRicbpTsDO3/oqmVtZpmIDY2HPOeWIZChuLfMDwT3FTUkDjQpsq390
OJ90pArd1JRxdIZtnCvnVy/vg+1MjAFH3ta+CuAwHsIY/3lGOKTin1+5M30BKh7NOQMmBcJ8/RuL
TfXMGQT01QVMeAGq6vORk3iw39KOLRU3Lcn1804G1/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 = 94424081139901371883469166542407095517576260048697655243
q = 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) = 7467492769579356967270197440403790283193525917787433197058250305765111796388761610844354228288301399878958918760
d = 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: SHA1

This song is your own path
Another stop on the road toward enlightenment
Follow 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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bE94Nrpi0URzQkNJ1JGW3aH2KEDm4jnKzsKQM0UUU3aIKSKnBSQJu0zKkC+ywXoE
1bNzm0BNYQ7ij5j5JnRJrIQAJzTQEAaFOYLgm3Q6WZv9rtA6F/TzWzLIHHYsqGAO
ag5XfhrYb0Vu0gikoUw7+S1psSF4HaXqNiXJ+ujKzq8ud4D9vcgfTbk2WHoVlM/2
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Ehzy11d2LhDgm+VTx7SRDdqwmAmuzZ4DNLIhKYjZlUL9BuoKspdXaBxbF0MBA/+O
W2wBkWmofUCmdkLCFHhsJYCZoDdGNhVdiCaIFtECvlYTJoEPxBu/lcWZYiNoywKE
8wIDzK3KDRURfYt6Wah0CLvSBp5GQnRKvzhB4yWEmyhL/HZE62AHheZ4aI6H5nho
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=yk7h
- -----END PGP MESSAGE-----
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.11 (GNU/Linux)

iQIcBAEBAgAGBQJPGOY0AAoJEBgfAeV6NQkP7KQQAJ7qfuZgtthyD6hXiPvrYXCl
Dnbj4viLPeiwVC/dYHn76yixqImr4+gzWEGzr+MrNpaPRBtCxu7kmBtwuyNHoqlz
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sppcEaykOHUmz+cxG2xpOD1KVt/IqSawimB3xfveCcLyRRfRQp4ACyL+eBiTzuT9
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FZL1IQd0u3QtmG5aRBhi
=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 mido

def 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 result

def 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 result

print(notesToSingleLetters(getNotes('cicada-3301-2012-midi-song.midi', 1)))

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

Cicada Midi File decoded
Cicada Midi File decoded

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:

Cicada 3301 end (original file)
The end of the 2012 puzzle

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

Learn more about the mysteries at the Uncovering Cicada fandom.