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The National Cipher Challenge

Challenge 2

RULE REMINDER: Rapid fire multiple submissions put an unreasonable load on the servers and make it difficult for others to submit. Anyone who makes an unreasonable number of submissions will be open to disqualification. In the first instance this will mean that anyone who submits more than 20 times in 10 minutes will be disqualified.

First time here? Your task is to try and decipher the text below. There are two parts to the Challenge, part A and part B, and you should try to decipher both of them, but you will get a score for each one, so don’t worry if you can’t break one of them this week. The text you can see below is part A of Challenge 2, so spend a little time trying to break it, and when you have, then you (or your team captain if you are not the captain of your team), should paste your solution in the box at the bottom of the page and press the submit button.

The official BOSS deciphering tools page

Playing games

SEJKG XLXOK TJOSA YZIUS SKTJE UAUTE UAXZG YZKOT ZNKGZ XKGYC KRRGY OTIUS VGTOU TYEUA XYAMM KYZOU TZNGZ OYNUA RJGZZ KTJSS KHKXT NGXJZ YRGZK YZZXO ASVNC GYCKR RZOSK JYOTI KSEHA YOTKY YNGJH XUAMN ZSKZU VGXOY GTJRK LZSKO TTKKJ ULGJO YZXGI ZOUTC NORKZ NKSOR OZGXE GJBKT ZAXKO TKMEV ZNGYN GJSGT EJOVR USGZO IXGSO LOIGZ OUTYC NOINC ORRHK LKRZL UXYUS KZOSK ZNKOS VGIZU TUAXX KRGZO UTYCO ZNLXG TIKOY ZNKSU YZOSS KJOGZ KZNKS UUJNK XKOYJ OYZOT IZREA TKGYE ZNKAT JKXYZ GTJOT MZNGZ UAXOT ZKXKY ZYOTZ NGZIU ATZXE CKXKY NGXKJ NGYHK KTHGJ REYNG QKTGT JCOZN ZNKZC UMUBK XTSKT ZYGXK XGZZR OTMZN KOXYG HXKYO LKGXZ NGZSG ZZKXY SGEEK ZCUXY KTGMG OTYZZ NKORR ZKSVK XKJJO YIAYY OUTYO CGYLU XIKJZ UNURJ COZNS EIUAT ZKXVG XZYOT VGXOY ZNKZO SKYVK TZCOZ NSSKH KXTNG XJZYZ UUJOT SGXQK JIUTZ XGYZY NKOYG CUSGT ULMXG IKGTJ IUTYO JKXGH RKGII USVRO YNSKT ZGTJO CGYKT ZXGTI KJHUZ NHENK XYQOR RGYGT GIZXK YYGTJ HENKX MOLZY GYGNU YZKYY YNKYK KSKJG HRKZU ATJKX YZGTJ ZNKJK KVIUT IKXTZ NGZOQ TUCEU AYNGX KLUXZ NKLAZ AXKUL GTMRU LXKTI NXKRG ZOUTY GTJOZ NOTQY NKCOR RVXUB KGBKX EAYKL ARGRR EOTUA XGZZK SVZYZ UYZGH OROYK ZNKYO ZAGZO UTYNK IRKGX RENGY ZNKKG XULSG TEOTL RAKTZ OGRSK SHKXY ULVGX OYOGT YUIOK ZEGTJ ULZNK MUBKX TSKTZ OZYKR LGTJO ZNOTQ CKCUA RJHKC OYKZU KTROY ZNKXO TUAXK LLUXZ YHKEU TJZNG ZOSAY ZGJSO ZSEGY ZUTOY NSKTZ GZNKX KBOJK TZYQO RRGYG YIARV ZXKYY ONGJN KGXJZ NGZYN KCGYG MOLZK JGXZO YZHAZ NGJGY YASKJ ZNOYX KLKXX KJZUN KXYQO RRCOZ NHXAY NGTJI GTBGY OJUTZ ZNOTQ EUANG JSKTZ OUTKJ ZNGZZ NKKDZ XGUXJ OTGXE HXUTF KOTQC KRRUT EUAXJ KYQOT ZNKYZ AJEGZ SGXRH UXUAM NNUAY KCGYG YKRLV UXZXG OZXKT JKXKJ HENKX OLEUA NGJZN KTONG JLUXM UZZKT OZGTJ OUTRE XKGRO YKJZN KIUTT KIZOU TCNKT YNKYN UCKJS KGSUJ KRYNK NGJSG JKOTV XKVGX GZOUT LUXZN KLOTG RUHPK IZZNK YZXGT MKTKY YULZN KZNOT MCOZN OZYHG ZCOTM YGTJY KVARI NXGRG OXOYG RSUYZ YOTMA RGXOT OZYKL LKIZG TJOCG YOSSK JOGZK REJXG CTZUG YQNKX GHUAZ OZCNK XKAVU TYNKI UTLOJ KJZNK IUTTK IZOUT COZNE UAHKL UXKOI UTIRA JKOSA YZOSV XKYYA VUTEU AUTKS GZZKX ULVGX ZOIAR GXOSV UXZGT IKLUX ZNKVX UZKIZ OUTUL AYGRR ZNKMX UCOTM ORRLK KROTM GIXUY YZNKI NGTTK RVXKY KTZYH UZNGJ GTMKX GTJGT UVVUX ZATOZ EOLCK SGQKU AXSUB KYCOY KREOZ NOTQC KSGEL UXMKG VUCKX LARTK CGRRO GTIKG YOTMR KLGRY KSUBK NUCKB KXIUA RJIUY ZAYJK GXREG TJVRG IKUAX LXOKT JYGTJ GRROK YOTIU TYOJK XGHRK JGTMK XOZOY KYYKT ZOGRZ NGZCK ZGQKI GXKZU IUTIK GRUAX VRGTY GTJOY AMMKY ZZNGZ CKKTY AXKZN KYKIX KIEUL UAXIU XXKYV UTJKT IKHEG JUVZO TMSUX KYKIA XKIOV NKXYO LEUAG MXKKZ NKTOY NGRRV XKVGX KGYIN KJARK ULIOV NKXQK EYZUY NGXKC OZNSS KHKXT NGXJZ GTJCO ZNEUA CNKTO XKZAX TLXUS KMEVZ OYNGR RHKZX GBKRR OTMZN KXKUT IKSEH AYOTK YYNKX KOTVG XOYOY IUTIR AJKJC NORKZ NKXKG XKSUX KYKIA XKSKZ NUJYZ NGZOQ TUCEU ANGBK HKKTZ XGOTK JZUAY KOLKG XZNGZ ZNKJO BOTKY HNGYR KYYKD VKXOK TIKOT YAINS GZZKX YGTJY UOYNG RRXKI USSKT JZNGZ CKAYK GQKEC UXJYA HYZOZ AZOUT IOVNK XLUXU AXLAZ AXKIU SSATO IGZOU TYUTI KYNKO YIUSL UXZGH RKCOZ NZNGZ YEYZK SCKSO MNZVK XNGVY SUBKU TZUUZ NKXYZ NGZGL LUXJK BKTMX KGZKX YKIAX OZEOG CGOZE UAXXK VREEU AXLXO KTJKI

A vintage map of Egypt in 1882

As we mentioned above this is where you can submit your solution. Since this is a practice challenge we will give you feedback for your submission so you can try to improve it if it is not quite right. If there are too many mistakes then we won’t do that, as we don’t want to encourage you to just guess!

Official Decrypt

Top Secret: For your eyes only

My dear friend, I must commend you on your taste in theatre as well as in companions. Your suggestion that I should attend Mme Bernhardt’s latest triumph was well timed, since my business had brought me to Paris and left me in need of a distraction. While the military adventure in Egypt has had many diplomatic ramifications which will be felt for some time, the impact on our relations with France is the most immediate. The mood here is distinctly uneasy. The understanding that our interests in that country were shared has been badly shaken, and with the two governments are rattling their sabres I fear that matters may yet worsen. Against the ill-tempered discussions I was forced to hold with my counterparts in Paris, the time spent with Mme Bernhardt stood in marked contrast. She is a woman of grace and considerable accomplishment, and I was entranced both by her skill as an actress and by her gifts as a hostess. She seemed able to understand the deep concern that I know you share for the future of Anglo-French relations, and I think she will prove a very useful ally in our attempts to stabilise the situation. She clearly has the ear of many influential members of Parisian society and of the government itself, and I think we would be wise to enlist her in our efforts. Beyond that, I must admit my astonishment at her evident skill as a sculptress. I had heard that she was a gifted artist but had assumed this referred to her skill with brush and canvas. I don’t think you had mentioned that the extraordinary bronze inkwell on your desk in the study at Marlborough House was a self-portrait rendered by her. If you had, then I had forgotten it, and I only realised the connection when she showed me a model she had made in preparation for the final object. The strangeness of the thing, with its bat wings and sepulchral air, is almost singular in its effect, and I was immediately drawn to ask her about it, whereupon she confided the connection with you. Before I conclude, I must impress upon you one matter of particular importance, for the protection of us all. The growing ill feeling across the Channel presents both a danger and an opportunity. If we make our moves wisely, I think we may forge a powerful new alliance. A single false move, however, could cost us dearly, and place our friends and allies in considerable danger. It is essential that we take care to conceal our plans, and I suggest that we ensure the secrecy of our correspondence by adopting more secure ciphers. If you agree, then I shall prepare a schedule of cipher keys to share with Mme Bernhardt, and with you when I return from Egypt. (I shall be travelling there once my business here in Paris is concluded.) While there are more secure methods that I know you have been trained to use, I fear that the Divine SB has less experience in such matters, and so I shall recommend that we use a keyword substitution cipher for our future communications. Once she is comfortable with that system, we might perhaps move on to others that afford even greater security. I await your reply. Your friend, EC

Exposed?

OPDL GL PFAIN, A QHOPLMNDHO XLIG IQL GQNQDF XLAPHO JLIXPMMIL RDHOARPL NZDN VIQ DLP SQLLPHNFV IXXPLAHY NI QHOPLNDCP AHRPMNAYDNAIHM NZDN LPKQALP OAMSLPNAIH IH EINZ IQL JDLNM. TZAFP A TIQFO QMQDFFV JLPXPL NI PHYDYP NZP MPLRASPM IX MIGPIHP TANZ GILP PUJPLAPHSP, NZPLP DLP LPDMIHM, TZASZ A TAFF HIN OAMSFIMP HIT, TZV ZP NZAHCM VIQ GDV EP DEFP NI DMMAMN QM. A LPJLPMPHN D YLIQJ IX PQLIJPDH AHRPMNILM TZI DLP XAHDHSAHY DH DRADNAIH OISQGPHNDLV EPAHY JLIOQSPO EV GIHDLSZ JASNQLPM, DHO TZI DLP HIT XDSAHY NZP FIMM IX NZPAL AHRPMNGPHN ITAHY NI NZP GVMNPLAIQM OAMDJJPDLDHSP IX AGJILNDHN XAFG XIINDYP DMMPGEFPO EV NZP JLIOQSPL DHO OALPSNIL. NZP XIINDYP ZDO NDCPH SIHMAOPLDEFP NAGP DHO PXXILN NI DMMPGEFP DHO TDM MNILPO AH MAU MPDFPO SDHM. MIGP IX AN ZDO EPPH SIGGAMMAIHPO MJPSAXASDFFV XIL NZAM GINAIH JASNQLP, EQN TZPH NZP SDH SIHNDAHAHY NZDN GDNPLADF TDM IJPHPO AH NZP SQNNAHY LIIG, AN TDM OAMSIRPLPO NZDN NZP XAFG SIHNDAHPO HI AGDYPM. AN TDM DM AX NZP PGQFMAIH ZDO HPRPL EPPH PUJIMPO. NZAM, IX SIQLMP, AM JLPJIMNPLIQM, DHO A SDH IHFV SIHSFQOP NZDN NZP ILAYAHDF XIINDYP ZDM EPPH MNIFPH, NZIQYZ ZIT DHO EV TZIG A SDHHIN NPFF. TZDN A SDH MDV AM NZDN NZP RDFQP IX NZP GAMMAHY XIINDYP AM AGGPHMPFV AHSLPDMPO EV NZP XDSN NZDN AN AM SIHHPSNPO TANZ JFDHM XIL DH IRPLMPDM SIGGPLSADF RPHNQLP OPJPHOPHN QJIH NZP MQSSPMM IX NZAM JASNQLP. TZAFP NZP XAFG ANMPFX AM QHFACPFV NI GDCP GIHPV, AN TDM ZIJPO NZDN AN TIQFO JFDV D MAYHAXASDHN LIFP AH JLIGINAHY DGPLASDH DSZAPRPGPHNM AH DRADNAIH, DHO NZDN NZP LPMQFNAHY IRPLMPDM MDFPM TIQFO JLIRAOP D ZDHOMIGP LPNQLH XIL NZP AHRPMNILM. TZAFP NZAM GAYZN DJJPDL NI LPKQALP IHFV NZP MPLRASPM IX IHP IX NZP GDHV JLARDNP OPNPSNARP DYPHSAPM AH FIM DHYPFPM, IHP JPSQFADL XPDNQLP IX NZP SDMP SDFFM XIL DOOANAIHDF MCAFFM NZDN JLIXPMMIL RDHOARPL EPFAPRPM VIQ SDH JLIRAOP. IQL SZAPX MQMJPSN, D BQHAIL GPGEPL IX NZP JZINIYLDJZAS NPDG, OAMDJJPDLPO DN NZP MDGP NAGP DM NZP XAFG XIINDYP. ZP ZDO EPPH FIOYAHY DN D EIDLOAHY ZIQMP HPDL NZP MNQOAI DHO DJJPDLM NI ZDRP FPXN AH MQSZ ZDMNP NZDN ZP IRPLFIICPO IHP SFQP: DH DJJDLPHNFV PHSAJZPLPO FPNNPL. DM VIQ ZDRP DFLPDOV OPNPLGAHPO, GV FPNNPL NI VIQ AM DFMI PHSAJZPLPO, DHO A DJIFIYAMP XIL NZDN. AN GQMN ZDRP EPPH D MQLJLAMP NI IJPH D OISQGPHN SIHNDAHAHY DH QHAHNPFFAYAEFP MNLAHY IX FPNNPLM, EQN AX VIQ JIMMPMM NZP MCAFFM NZDN JLIXPMMIL RDHOARPL DMMQLPM GP VIQ ZDRP, NZPH NZAM MZIQFO HIN ZDRP JLPMPHNPO NII YLPDN D SZDFFPHYP. AX, IH NZP INZPL ZDHO, VIQ OI HIN, NZPH NZAM GPMMDYP TAFF LPGDAH QHLPDO, DHO A MZDFF HPPO NI MPPC ZPFJ PFMPTZPLP. YARPH NZP AGJILNDHSP DHO RDFQP IX NZAM QHOPLNDCAHY, DHO TZDN JLIXPMMIL RDHOARPL ZDM NIFO GP DEIQN VIQ, A SDH DMMQLP VIQ NZDN NZP MQSSPMMXQF SIHSFQMAIH IX NZAM AHRPMNAYDNAIH TAFF OI GQSZ NI MPSQLP VIQL XQNQLP, DM TPFF DM NZP AHNPLPMNM IX GV SFAPHNM. VIQLM MAHSPLPFV, ELPHOD ZDLNXILO

The filmstock

As usual, paste your decrypt here and press submit to get some feedback. You can see your scores and download certificates from your account area on the website.

Official Decrypt

Top Secret: For your eyes only

Dear Mr Eliot, I understand from our mutual friend Professor Vandiver that you are currently offering to undertake investigations that require discretion on both our parts. While I would usually prefer to engage the services of someone with more experience, there are reasons, which I will not disclose now, why he thinks you may be able to assist us. I represent a group of European investors who are financing an aviation documentary being produced by Monarch Pictures, and who are now facing the loss of their investment owing to the mysterious disappearance of important film footage assembled by the producer and director. The footage had taken considerable time and effort to assemble and was stored in six sealed cans. Some of it had been commissioned specifically for this motion picture, but when the can containing that material was opened in the cutting room, it was discovered that the film contained no images. It was as if the emulsion had never been exposed. This, of course, is preposterous, and I can only conclude that the original footage has been stolen, though how and by whom I cannot tell. What I can say is that the value of the missing footage is immensely increased by the fact that it is connected with plans for an overseas commercial venture dependent upon the success of this picture. While the film itself is unlikely to make money, it was hoped that it would play a significant role in promoting American achievements in aviation, and that the resulting overseas sales would provide a handsome return for the investors. While this might appear to require only the services of one of the many private detective agencies in Los Angeles, one peculiar feature of the case calls for additional skills that Professor Vandiver believes you can provide. Our chief suspect, a junior member of the photographic team, disappeared at the same time as the film footage. He had been lodging at a boarding house near the studio and appears to have left in such haste that he overlooked one clue: an apparently enciphered letter. As you have already determined, my letter to you is also enciphered, and I apologise for that. It must have been a surprise to open a document containing an unintelligible string of letters, but if you possess the skills that Professor Vandiver assures me you have, then this should not have presented too great a challenge. If, on the other hand, you do not, then this message will remain unread, and I shall need to seek help elsewhere. Given the importance and value of this undertaking, and what Professor Vandiver has told me about you, I can assure you that the successful conclusion of this investigation will do much to secure your future, as well as the interests of my clients. Yours sincerely, Brenda Hartford

This challenge closed on 21/10/2026. Please click the Official Decrypt button above to see the correct answers.

RULE REMINDER: Rapid fire multiple submissions put an unreasonable load on the servers and make it difficult for others to submit. Anyone who makes an unreasonable number of submissions will be open to disqualification. In the first instance this will mean that anyone who submits more than 20 times in 10 minutes will be disqualified.

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