Caesar Shift (Substitution Cipher)

A Caesar Shift cipher is a type of mono-alphabetic substitution cipher where each letter of the plain text is shifted a fixed number of places down the alphabet. For example, with a shift of 1, letter A would be replaced by letter B, letter B would be replaced by letter C, and so on. This type of substitution Cipher is named after Julius Caesar, who used it to communicate with his generals.

Key +5
Plain text alphabet: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
shift-5-places
Cipher text alphabet: F G H I J K L M N O P Q R S T U V W X Y Z A B C D E

This type of cipher is a form of symmetric encryption as the same key can be used to both encrypt and decrypt a message. (e.g. If a message is encrypted with a key of +5, it can be decrypted with a key of -5).

You can generate your own encryption keys and encrypt your own messages using our online Caesar Shift substitution engine:

Frequency Analysis


One approach used to help decrypt a Caesar shift substitution cipher is to use a frequency analysis based on counting the number of occurrence of each letter to help identify the most recurrent letters. (e.g. In the English language, letters E, T and A).

Your Task:


Complete a frequency analysis to decrypt the following ciphers.
Cipher #1Cipher #2Cipher #3
“ZE KYV KFNE NYVIV Z NRJ SFIE
CZMVU R DRE NYF JRZCVU KF JVR
REU YV KFCU LJ FW YZJ CZWV
ZE KYV CREU FW JLSDRIZEVJ
JF NV JRZCVU LG KF KYV JLE
‘KZC NV WFLEU R JVR FW XIVVE
REU NV CZMVU SVEVRKY KYV NRMVJ
ZE FLI PVCCFN JLSDRIZEV
NV RCC CZMV ZE R PVCCFN JLSDRIZEV
PVCCFN JLSDRIZEV, PVCCFN JLSDRIZEV
NV RCC CZMV ZE R PVCCFN JLSDRIZEV
PVCCFN JLSDRIZEV, PVCCFN JLSDRIZEV
REU FLI WIZVEUJ RIV RCC RSFRIU
DREP DFIV FW KYVD CZMV EVOK UFFI
REU KYV SREU SVXZEJ KF GCRP
NV RCC CZMV ZE R PVCCFN JLSDRIZEV
PVCCFN JLSDRIZEV, PVCCFN JLSDRIZEV
NV RCC CZMV ZE R PVCCFN JLSDRIZEV
PVCCFN JLSDRIZEV, PVCCFN JLSDRIZEV
(WLCC JGVVU RYVRU DI. GRIBVI, WLCC JGVVU RYVRU
WLCC JGVVU RYVRU ZK ZJ, JVIXVREK
RTKZFE JKRKZFE, RTKZFE JKRKZFE
RPV, RPV, JZI, WZIV
TRGKRZE, TRGKRZE)
RJ NV CZMV R CZWV FW VRJV
VMVIPFEV FW LJ YRJ RCC NV EVVU (YRJ RCC NV EVVU)
JBP FW SCLV (JBP FW SCLV) REU JVR FW XIVVE (REU JVR FW XIVVE)
ZE FLI PVCCFN JLSDRIZEV (ZE FLI PVCCFN, JLSDRIZEV, YR YR)
NV RCC CZMV ZE R PVCCFN JLSDRIZEV
PVCCFN JLSDRIZEV, PVCCFN JLSDRIZEV
NV RCC CZMV ZE R PVCCFN JLSDRIZEV
PVCCFN JLSDRIZEV, PVCCFN JLSDRIZEV
NV RCC CZMV ZE R PVCCFN JLSDRIZEV
PVCCFN JLSDRIZEV, PVCCFN JLSDRIZEV
NV RCC CZMV ZE R PVCCFN JLSDRIZEV
PVCCFN JLSDRIZEV, PVCCFN JLSDRIZEV”

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“WAOUWBS HVSFS’G BC QCIBHFWSG
WH WGB’H VOFR HC RC
BCHVWBU HC YWZZ CF RWS TCF
OBR BC FSZWUWCB, HCC
WAOUWBS OZZ HVS DSCDZS
ZWJWBU ZWTS WB DSOQS
MCI, MCI AOM GOM W’A O RFSOASF
PIH W’A BCH HVS CBZM CBS
W VCDS GCASROM MCI KWZZ XCWB IG
OBR HVS KCFZR KWZZ PS OG CBS
WAOUWBS BC DCGGSGGWCBG
W KCBRSF WT MCI QOB
BC BSSR TCF UFSSR CF VIBUSF
O PFCHVSFVCCR CT AOB
WAOUWBS OZZ HVS DSCDZS
GVOFWBU OZZ HVS KCFZR
MCI, MCI AOM GOM W’A O RFSOASF
PIH W’A BCH HVS CBZM CBS
W VCDS GCASROM MCI KWZZ XCWB IG
OBR HVS KCFZR KWZZ ZWJS OG CBS”

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“SBRL ZRFDHSRLY OHZ YLABYULK AV OPZ OVTL WSHULA VM AHAVVPUL PU HU HAALTWA AV YLZJBL OPZ MYPLUK OHU ZVSV MYVT AOL JSBAJOLZ VM AOL CPSL NHUNZALY QHIIH AOL OBAA.

SPAASL KVLZ SBRL RUVD AOHA AOL NHSHJAPJ LTWPYL OHZ ZLJYLASF ILNBU JVUZAYBJAPVU VU H ULD HYTVYLK ZWHJL ZAHAPVU LCLU TVYL WVDLYMBS AOHU AOL MPYZA KYLHKLK KLHAO ZAHY.

DOLU JVTWSLALK, AOPZ BSAPTHAL DLHWVU DPSS ZWLSS JLYAHPU KVVT MVY AOL ZTHSS IHUK VM YLILSZ ZAYBNNSPUN AV YLZAVYL MYLLKVT AV AOL NHSHEF…”


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