Caesar Cipher Tool
Encode or decode text with any shift from 1 to 25, use ROT13 in one click, or see all 25 shifts at once.
Dieser Inhalt ist auf Englisch.
Durchgerechnete Beispiele
Shifting letters by three
Hello, World with a shift of 3
Khoor, Zruog
Each letter moves three places along the alphabet, and punctuation and spaces are left alone.
ROT13 of a word
Hello with ROT13 selected
Uryyb
ROT13 shifts by 13 places, so applying it again gives back the original text.
Über Caesar Cipher Tool
A Caesar cipher is one of the oldest and simplest ways to disguise writing. Each letter is moved along the alphabet by a fixed number of places, so a shift of three turns A into D and B into E. When the end of the alphabet is reached the count wraps round, so X, Y and Z become A, B and C. This tool applies any shift from 1 to 25 to your text, in either direction, and keeps capital letters, numbers, spaces and punctuation exactly where they were.
The tool also includes ROT13, which is a Caesar cipher with a shift of 13. Because the alphabet has 26 letters, applying ROT13 twice returns the original text, so one button both hides and reveals a message. If you do not know the shift used on a message, the all 25 shifts view lists every possible result on one screen. The cipher is simple enough to break quickly, so it is best used for puzzles, classroom activities and learning how substitution works.
So verwenden Sie Caesar Cipher Tool
- Type or paste your text into the Your text box.
- Enter a shift from 1 to 25, or select ROT13 to use a shift of 13.
- Choose Encode to scramble the text, or Decode to reverse a shift that someone else used.
- Tick Show all 25 shifts when you need to see every possible result, then copy the one that reads correctly.
Typische Einsatzzwecke
- Making a simple code for a classroom or a scout activity
- Hiding the answer to a riddle or crossword clue until it is read
- Reading a message in a puzzle book that uses a known shift
- Learning how substitution ciphers work in a history or maths lesson
Häufige Fragen
What is a Caesar cipher?
A Caesar cipher replaces each letter with another letter a fixed number of places further along the alphabet. It is named after Julius Caesar, who is said to have used a shift of three. The same shift is used to encode and decode, so the person who receives the message only needs to know the number to read it.
What is ROT13?
ROT13 is a Caesar cipher with a shift of 13. Because 13 is exactly half of 26, encoding and decoding are the same operation, and applying ROT13 twice gives back the original text. It is often used on forums and puzzle sites to hide spoilers or answers, so that a reader has to choose to reveal them.
Can a Caesar cipher hide sensitive information?
No. A Caesar cipher has only 25 possible shifts, so anyone can try them all in a few seconds. This tool is for puzzles, games and learning about how ciphers work. For anything that matters, use a method designed for that purpose and not a shift of letters, because a simple cipher like this offers no real protection.
What does the Show all 25 shifts option do?
It lists the result for every shift from 1 to 25 in one table. In Encode mode each row shows the text scrambled with that shift, and in Decode mode each row shows the text decoded with that shift. This is a quick way to test a message when you do not know the shift, since one row will normally read as ordinary language.
How are numbers, spaces and punctuation handled?
Only the letters A to Z and a to z are shifted. Capital letters stay capitals and lower case letters stay lower case, while numbers, spaces, line breaks and punctuation are kept unchanged. This means the layout of your message stays the same and only the letters change, which makes the result easy to check against the original.