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.
With this challenge the competition starts in earnest. At the end of Challenge 4 we will publish a new overall leaderboard for each part which will accumulate your scores for the part A challenges to give the part A overall leaderboard and … well you get the idea.
As with the practice challenges speed does not matter for the part A challenges, only accuracy, while for part B you will get a score based on your accuracy AND your speed. The deadlines for the speed points are published alongside each challenge B.
For now we will continue to give instant feedback, so you will be able to see if you have completed the challenge or need to try again, but later in the competition we will delay feedback to reward those who manage to get it right first time. That won’t stop you from trying to find your own mistakes and you can always resubmit until you get it right (or until the end of the round at least) and doing that can never reduce your marks.
Good luck, Harry
Derby
WINOK BVYBN NOBLI SWECD KNWSD DYCYW OMYXP ECSYX KPDOB BOKNS XQIYE BVODD OBKCS MKXXY DMVOK BVICO ORYGS WSQRD LOYPK XIKCC SCDKX MODYI YEZOB RKZCD RKDCR YGCKG KXDYP SWKQS XKDSY XYXWI ZKBDL EDSDB EVIPK SVDYC OORYG KXIDR SXQSM YEVNN YGYEV NRKFO DROVO KCDSX PVEOX MOEZY XDROQ BOKDK PPKSB CXYGC DSBBS XQKMB YCCDR OYMOK XIYEK BOAES DOBSQ RDDRK DGOCR KBOKN OOZNS CVSUO YPDRK DNBOK NPEVS XCDSD EDSYX CVKFO BIKXN SBOTY SMONK CIYEN SNKDD ROFSM DYBSO CYPWB VSXMY VXKXN DROXO GRYZO DROIL BSXQD YCYWK XIVYX QCEPP OBSXQ ZOYZV OIODS MKXXY DLOVS OFODR KDKXI DRSXQ SWSQR DGBSD OYBCK IMYEV NWYFO DROMY XQBOC CYBDR OZBOC SNOXD DYGKB NCKTE CDMYE BCOSP IYEBY GXOPP YBDCR KFOXY DKVBO KNIZO BCEKN ONDRO WXYXO DROVO CCWBL KLLKQ OSCWY CDSXC SCDOX DDRKD SCRYE VNROK BIYEB CMROW OKXNS GSVVL OSXVY XNYXX OHDGO OUPYB KWOOD SXQYP DROQR YCDMV ELSPI YEKBO GSVVS XQGOW SQRDW OODDR OBOYB SPIYE ZBOPO BKAES ODOBC ODDSX QKDDR OKDRO XOEWS BOWKS XWINO KBVYB NNOBL IFOBI DBEVI IYEBC MRKBV OCNSM UOXC
Very little to go on here, but do take a look at the Tips published above if you are stuck, and keep an eye out for additional help in the Case Files.
This is where you can submit your solution. If you make a mistake but can’t see any feedback on where you have gone wrong there are two possibilities. One is that you have missed something from the end of your solution so our checker has nothing to underline. The other is that you have made a few too many mistakes and the checker has decided you need to work on your solution a bit more before it can help!
Top Secret: For your eyes only
My dear Lord Derby, I must admit to some confusion after reading your letter, as I cannot clearly see how I might be of any assistance to you. Perhaps that shows a want of imagination on my part, but I truly fail to see how anything I could do would have the least influence upon the great affairs now stirring across the ocean. You are quite right that we share a deep dislike of that dreadful institution, slavery, and I rejoiced — as you did — at the victories of Mr. Lincoln and the new hope they bring to so many long-suffering people. Yet I cannot believe that anything I might write or say could move the Congress or the President towards a just course, if your own efforts have not already persuaded them. Nonetheless, Mr. Babbage is most insistent that I should hear your scheme, and I will be in London next week for a meeting of the Ghost Club. If you are willing, we might meet there, or, if you prefer a quieter setting, at the Atheneum. I remain, my dear Lord Derby, Very truly yours, Charles DickensConfidential
IFQFUDN EREIF, K JDYF HRNNRZFE BRXU ZRUM ZKWJ IUFDW KQWFUFVW DQE JDYF OFFQ PRVW KPSUFVVFE ZKWJ BRXU FQFUIFWKG EFYFNRSPFQW DQE SURPRWKRQ RH WJF QRUWJ DPFUKGDQ WFNFIUDSJKG VBVWFP. K JDYF VSFQW PDQB BFDUV VWXEBKQI PDWJFPDWKGV DQE FQIKQFFUKQI, EKVGXVVKQI WJF GJDNNFQIFV KQYRNYFE KQ FNFGWUKGDN WUDQVPKVVKRQ DQE VWRUDIF RH KQHRUPDWKRQ ZKWJ PB HUKFQE DQE GRNNFDIXF GJDUNFV ZJFDWVWRQF. K ZDV EFNKIJWFE ZJFQ BRX DSSURDGJFE PF ZKWJ BRXU SURSRVDN DQE JDYF VSFQW PDQB JRXUV EKVGXVVKQI KW ZKWJ PB GNRVFVW GRQHKEDQWFV. OFBRQE RXU GRPPRQ KQWFUFVWV DV PFQ RH VGKFQGF, BRXU NFWWFU GRQYKQGFE PF WJDW ZF DNVR VJDUF D GRQGFUQ HRU JXPDQKWB DQE NKOFUWB, DQE K WJKQM K GDQ VFF JRZ RXU GRPSNFPFQWDUB VMKNNV GRXNE SURHKWDONB GRPOKQF WR WJF OFQFHKW RH HUFF PFQ FYFUBZJFUF. K DP UFNXGWDQW WR GRPPKW PB GRPPFQWV RQ BRXU KEFD WR SDSFU, FYFQ VFGXUFE ZKWJ WJKV GKSJFU, SDUWNB OFGDXVF PB RZQ UFVFDUGJ JDV VJRZQ LXVW JRZ KNNXVKYF WJDW VFGXUKWB GDQ OF. IKYFQ WJRVF GRQGFUQV K ZRXNE SUFHFU WR EKVGXVV PDWWFUV KQ SFUVRQ, OXW K DP WRR RNE HRU WJF UKIRXUV RH DQ RGFDQ GURVVKQI. HRUWXQDWFNB, PB EFDU HUKFQE PU GJDUNFV EKGMFQV KV SNDQQKQI WR YKVKW BRXU GRXQWUB VJRUWNB, DQE K DP JRSKQI WJDW K ZKNN OF DONF WR SFUVXDEF JKP WR DGW DV DQ KQWFUPFEKDUB. JF KV UFNXGWDQW WR IFW KQYRNYFE KQ DHHDKUV RH VWDWF, OXW WJF SUKPF PKQKVWFU, NRUE EFUOB JDV KQEKGDWFE JKV VXSSRUW HRU BRXU VXIIFVWKRQ, DQE SFUJDSV JKV IKHW HRU SFUVXDVKRQ ZKNN FQGRXUDIF PU EKGMFQV WR FQIDIF ZKWJ XV. K JRSF BRX ZKNN QRW PKQE PF FPSJDVKVKQI WJF QFFE HRU GRPSNFWF GRQHKEFQWKDNKWB GRQGFUQKQI WJKV NFWWFU. KH BRX JDYF EFGKEFE RQ UFHNFGWKRQ QRW WR WDMF WJKV PDWWFU HXUWJFU, WJFQ SNFDVF EFVWURB WJKV SDSFU DQE ZF ZKNN VSFDM QR PRUF RQ WJKV VXOLFGW. KH, JRZFYFU, BRX DUF KQWFUFVWFE KQ EFYFNRSKQI BRXU KEFD HXUWJFU ZKWJ XV WJFQ K ZRXNE VXIIFVW DSSNBKQI RQF RH WJF PRUF VFGXUF PREFUQ GKSJFUV WR BRXU UFSNB. K ZKNN HXUQKVJ BRX ZKWJ VXKWDONB EKVIXKVFE MFBV OB WFNFIUDP. ZKWJ PB YFUB OFVW ZKVJFV, GJDUNFV ODOODIF
If you can’t submit a solution there are several things that could have gone wrong:
1. You might not have completed your registration. If you requested to join a team then you need to get that request approved by the captain, or if for some reason you didn’t complete the process of setting up a team then you will need to do that before you can submit. Log out of your account and log in again. You will be asked to complete your registration if that is the case.
2. You are not the team captain. Only captains can submit solutions for their teams. If you are not the captain and your captain can’t submit the solution then you need to get them to delegate the captaincy to you or another member of the team so you are able to submit on the team’s behalf.
3. You have already successfully completed this challenge and got a score of 100%. You don’t need to do it again!
If you can’t submit and don’t think any of the above apply to you then please email us at [email protected] to ask for help.
Top Secret: For your eyes only
General Dodge, I have followed your work with great interest and have been most impressed with your energetic development and promotion of the north American telegraphic system. I have spent many years studying mathematics and engineering, discussing the challenges involved in electrical transmission and storage of information with my friend and colleague Charles Wheatstone. I was delighted when you approached me with your proposal and have spent many hours discussing it with my closest confidantes. Beyond our common interests as men of science, your letter convinced me that we also share a concern for humanity and liberty, and I think I can see how our complementary skills could profitably combine to the benefit of free men everywhere. I am reluctant to commit my comments on your idea to paper, even secured with this cipher, partly because my own research has shown just how illusive that security can be. Given those concerns I would prefer to discuss matters in person, but I am too old for the rigours of an ocean crossing. Fortunately, my dear friend Mr Charles Dickens is planning to visit your country shortly, and I am hoping that I will be able to persuade him to act as an intermediary. He is reluctant to get involved in affairs of state, but the Prime Minister, Lord Derby has indicated his support for your suggestion, and perhaps his gift for persuasion will encourage Mr Dickens to engage with us. I hope you will not mind me emphasising the need for complete confidentiality concerning this letter. If you have decided on reflection not to take this matter further, then please destroy this paper and we will speak no more on this subject. If, however, you are interested in developing your idea further with us then I would suggest applying one of the more secure modern ciphers to your reply. I will furnish you with suitably disguised keys by telegram. With my very best wishes, Charles BabbageThis challenge closed on 12/11/2025. 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.