Vigenère cipher/Cryptanalysis: Difference between revisions

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Given some text you suspect has been encrypted with a Vigenère cipher, extract the key and plaintext. There are several methods for doing this. See the Wikipedia entry for more information. Use the following encrypted text:

MOMUD EKAPV TQEFM OEVHP AJMII CDCTI FGYAG JSPXY ALUYM NSMYH
VUXJE LEPXJ FXGCM JHKDZ RYICU HYPUS PGIGM OIYHF WHTCQ KMLRD
ITLXZ LJFVQ GHOLW CUHLO MDSOE KTALU VYLNZ RFGBX PHVGA LWQIS
FGRPH JOOFW GUBYI LAPLA LCAFA AMKLG CETDW VOELJ IKGJB XPHVG
ALWQC SNWBU BYHCU HKOCE XJEYK BQKVY KIIEH GRLGH XEOLW AWFOJ
ILOVV RHPKD WIHKN ATUHN VRYAQ DIVHX FHRZV QWMWV LGSHN NLVZS
JLAKI FHXUF XJLXM TBLQV RXXHR FZXGV LRAJI EXPRV OSMNP KEPDT
LPRWM JAZPK LQUZA ALGZX GVLKL GJTUI ITDSU REZXJ ERXZS HMPST
MTEOE PAPJH SMFNB YVQUZ AALGA YDNMP AQOWT UHDBV TSMUE UIMVH
QGVRW AEFSP EMPVE PKXZY WLKJA GWALT VYYOB YIXOK IHPDS EVLEV
RVSGB JOGYW FHKBL GLXYA MVKIS KIEHY IMAPX UOISK PVAGN MZHPW
TTZPV XFCCD TUHJH WLAPF YULTB UXJLN SIJVV YOVDJ SOLXG TGRVO
SFRII CTMKO JFCQF KTINQ BWVHG TENLH HOGCS PSFPV GJOKM SIFPR
ZPAAS ATPTZ FTPPD PORRF TAXZP KALQA WMIUD BWNCT LEFKO ZQDLX
BUXJL ASIMR PNMBF ZCYLV WAPVF QRHZV ZGZEF KBYIO OFXYE VOWGB
BXVCB XBAWG LQKCM ICRRX MACUO IKHQU AJEGL OIJHH XPVZW JEWBA
FWAML ZZRXJ EKAHV FASMU LVVUT TGK

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 Given some text you suspect has been encrypted with a Vigenère cipher, extract the key and plaintext. There are several methods for doing this. See [[wp:Vigenère_cipher#Cryptanalysis|the Wikipedia entry]] for more information. Use the following encrypted text:
 <pre>
-MOMUD EKAPV TQEFM OEVHP AJMII CDMPH WDYMD SQXEP DMALW NPXZF
+MOMUD EKAPV TQEFM OEVHP AJMII CDCTI FGYAG JSPXY ALUYM NSMYH
+VUXJE LEPXJ FXGCM JHKDZ RYICU HYPUS PGIGM OIYHF WHTCQ KMLRD
-BFZGS WBKKA YISUL XMOBE XPRVO IOHJV ENLFB TWADI JLBYI DOKHN
+ITLXZ LJFVQ GHOLW CUHLO MDSOE KTALU VYLNZ RFGBX PHVGA LWQIS
-SXLWS ULKLG MHFLV CALKV CKKTA UXIIY HVWAP VNCBU XYAQJ OEFAF
+FGRPH JOOFW GUBYI LAPLA LCAFA AMKLG CETDW VOELJ IKGJB XPHVG
-RVHXC HAUAL SAJZX GTAXJ PCDWL OIKGC TVAII YHVWA PVNWB CNIFK
+ALWQC SNWBU BYHCU HKOCE XJEYK BQKVY KIIEH GRLGH XEOLW AWFOJ
-YHSUL JLWNM ALJTB QAVCJ FCNWX YWPHX UOPVX QODAP WXVVH HTJAQ
+ILOVV RHPKD WIHKN ATUHN VRYAQ DIVHX FHRZV QWMWV LGSHN NLVZS
-RWBUL CUHDV VXXKM XMOIO HRPVU VJQEA XZSWN LLZWI IUTXW OIDFX
+JLAKI FHXUF XJLXM TBLQV RXXHR FZXGV LRAJI EXPRV OSMNP KEPDT
-ZLBLQ VUFMY IGHRV ZBFSF APAPP GPRLO WLKJT TGKEU PRMMN ZWJTA
+LPRWM JAZPK LQUZA ALGZX GVLKL GJTUI ITDSU REZXJ ERXZS HMPST
-HBKJA LWZBF SFTAX QEDII JDWTO YIMAL CGZSX MTRQG CTFLA JPJXS
+MTEOE PAPJH SMFNB YVQUZ AALGA YDNMP AQOWT UHDBV TSMUE UIMVH
-QEKVH KHBKJ ALWAC CKGYP HVHCU HTBZS PGDTL PXEHQ WVVVX YOHGL
+QGVRW AEFSP EMPVE PKXZY WLKJA GWALT VYYOB YIXOK IHPDS EVLEV
-XYVEF KBYVQ UZAHR FALJV CXLVH XOVVR HPTSI UIYEG MZRKJ OWYAE
+RVSGB JOGYW FHKBL GLXYA MVKIS KIEHY IMAPX UOISK PVAGN MZHPW
-EEKAX SIHAM LKMRH CNWPP XJPXK OMRHJ EPXUX IHPMT XYMPG UTJOC
+TTZPV XFCCD TUHJH WLAPF YULTB UXJLN SIJVV YOVDJ SOLXG TGRVO
-UHZHA KXJON LSEKU XZLRR FDEKP VGMJS ELBFQ AAKFZ QAIIS TQJLD
+SFRII CTMKO JFCQF KTINQ BWVHG TENLH HOGCS PSFPV GJOKM SIFPR
-ORHMV CINGB AUEAC TESSQ OGSST RCJEV AVVVS IVPVY MUJHR AACZF
+ZPAAS ATPTZ FTPPD PORRF TAXZP KALQA WMIUD BWNCT LEFKO ZQDLX
-JPTCM IAGWA LGZPA APPXQ VXLKM FNCJL IEHII FUSIK UXZLE RFGAE
+BUXJL ASIMR PNMBF ZCYLV WAPVF QRHZV ZGZEF KBYIO OFXYE VOWGB
-ETMOZ COLZV XJEUH YSIVZ WZIEH VHXFV QGYEL OAFYV GKTII KAWWL
+BXVCB XBAWG LQKCM ICRRX MACUO IKHQU AJEGL OIJHH XPVZW JEWBA
-UJZGR RIYIV ACKOM JEKDP ALRUO IZHLW MPILA LHKAF MAQKW TAMAL
+FWAML ZZRXJ EKAHV FASMU LVVUT TGK
-VJHVV AWLRF EKLAE PK
 </pre>