Purpose

  • Use this page to encrypt or decrypt text with a Caesar cipher.
  • Encrypt: paste your text in the 'clear text' box, pick your rotation offset, press 'Encrypt' and copy the result from the 'cipher text' box.
  • Decrypt: paste your text int the 'cipher text' box, and try different offsets until you see readable text in the 'clear text' box. The letter frequencies (or histogram) below can help you guess the correct offset (check the 'E' peak, and the 'R,S,T' triplet).

Caesar cipher algorithm

Alphabet shift
Cipher text:
Clear text:
Options
Case-sensitive (and leave accents)
Reverse input first
CIPHER TEXT
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
← smalleralphabet shiftbigger →
CLEAR TEXT
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
PICK "A"
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
Some typical letter frequencies in different european languages
ENGLISH TEXT
(EN)
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
FRENCH TEXT
(FR)
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
SPANISH TEXT
(ES)
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
GERMAN TEXT
(DE)
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
DUTCH TEXT
(NL)
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
References
  • Caesar cipher or 'shift cipher': most simple of the symmetric encryption algorithms - each letter is replaced by the letter X places further in the alphabet.
  • ROT-13: Caesar cipher that replaces each letter by the letter 13 places further in the alphabet ('A' -> 'N')

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Keywords
alfabet, algorithm, algoritme, alice, alphabet, bob, Cäsarchiffre, chiffre, cipher, cipher-text, clef, cryptography, decode, decryption, deutch, encode, encryption, espoñol, eve, français, frequency, geheim, histogram, key, nederlands, ontcijferen, plaintext, Schlüssel, secret, sleutel, substitution, symmetric, Verschiebung, Verschlüsselung, versleuteld, versleutelen, vervanging

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