O B Q F O B P B R P P C R G P C Q C S Q Q D S H Q D R D T R R E T I R E S E U S The word RETIRESE occurs in the fourth line, and, if the whole message be handled in this way we find the rest of the fourth line to read USTED POR EL MISMO ITINERARIO QUE MARCHO. The message was enciphered using an alphabet where A = X, B = Y, C = Z, D = A, etc. noting that as this message is in Spanish the letters K and W do not appear in the alphabet. Case 4-b. Message HUJZH UIUPN OZYTS VQXMI SMOMX MQHUD UMREI SESJU AG This is a message in Spanish. We will handle it as in case 4-a, setting down the whole message. HUJZHUIU PNOZY TSV QX MISMO MXMQHUDUMR EIS ESJUAG IVLAIVJV QOPAZ UTX RY A=A NYNRIVEVNS FJT FTLVBH JXMBJXLX RPQBA VUY SZ OZOSJXFXOT GLU GUMXCI LYNCLYMY SQRCB XVZ TA PAPTLYGYPU HMV HVNYDJ MZODMZNZ TRSDC YXA UB QBQUMZHZQV INX IXOZEL NAPENAOA USTED ZYB VC RCRVNAIARX JOY JYPAFM OBQFOBPB A=U AZC XD SDSXOBJBSY LPZ LZQBGN PCRGPCQC BAD YE TETYPCLCTZ MQA MARCHO QDSHQDRD CBE ZF UFUZQDMDUA NRB A=S RETIRESE DCF AG VGVARENEVB OSC A=Q EDG BH XHXBSFOFXC PTD FEH CI YIYCTGPGYD QUE GFI DJ ZJZDUHQHZE A=O HGJ EL ALAEVIRIAF IHL A=M BMBFXJSJBG JIM CNCGYLTLCH LJN DODHZMUMDI MLO EPEIANVNEJ NMP FQFJBOXOFL ONQ GRGLCPYPGM POR HSHMDQZQHN A=E ITINERARIO A=D Here each word of the message comes out on a different line, and noting in each case the letter corresponding to A, we have the word QUEMADOS which is the key. The cipher alphabet changed with each word of the message. A variation of this case is where the cipher alphabet changes according to a key word but the change comes every five letters or every ten letters of the message instead of every word. The text of the message can be picked up in this case with a little study. Note in using case 4 that if we are deciphering a Spanish message we use the alphabet without K or W as a rule, altho if the letters K or W appear in the cipher it is evidence that the regular English alphabet is used. Case 5-a. Message DNWLW MXYQJ ANRSA RLPTE CABCQ RLNEC LMIWL XZQTT QIWRY ZWNSM BKNWR YMAPL ASDAN