JCC: Online Caesar Cipher Calculator

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J C Cipher

OUTPUT

CONSOLE

INPUT

JCC = Julius Caesar's Cipher.

How to Use

This only shifts or rotates the alphabet (A to Z and a to z), 26 letters (52 — uppercase and lowercase).

  1. First, select a method: Encrypt or Decrypt.

  2. Type how many shifts (rotations) you want.

  3. Type or paste your text. The input is at the bottom.

  4. RUN button will be enabled. Hit it to calculate the result.

  5. There is an additional ALL button to show all rotations. Use it to show all shifts.

The Rotation

Minimum 1 and 25, max. ROT1 to ROT25, forwards (encrypt) or backwards (decrypt).

Well, Caesar did the forward shift for his encryption, so I use that reference.

Anyway.

It works as follows:

  • Encrypt — ROT1 or 1-place shift forwards.

    The letter A or a becomes B or b.

    Letter Z or z becomes A or a.

    Letter V or v becomes W or w.

    And so forth.

  • Decrypt — ROT1 or 1-place shift backwards.

    The letter A or a becomes Z or z.

    Letter Z or z becomes Y or y.

    Letter V or v becomes U or u.

    And so forth.

Mirrors:

  • Encrypt ROT1 is equivalent to Decrypt ROT25.

  • Encrypt ROT2 is equivalent to Decrypt ROT24.

  • Encrypt ROT3 is equivalent to Decrypt ROT23.

  • Encrypt ROT4 is equivalent to Decrypt ROT22.

  • Encrypt ROT5 is equivalent to Decrypt ROT21.

  • Encrypt ROT6 is equivalent to Decrypt ROT20.

  • Et cetera.

As you can see, it is the total number of letters in the alphabet, 26.

The Story

Around 50 BC, Julius Caesar had a problem. His letters to Cicero and his commanders passed through plenty of nosy couriers, and a wax seal was more of a polite suggestion than a lock.

So he shifted every letter three places along the alphabet, so A became D, B became E, and so on. His own name became Fdhvdu, try it with the application above. "Caesar" with 3-place shift (ROT3) encryption (forwards) .

Suetonius recorded the trick a century or so later, and the cipher has carried Caesar's name ever since.

It was hopelessly weak, of course. There are only 25 possible shifts, so any bored clerk with a spare afternoon could crack it. But in a world where most people could BARELY read plain Latin, it was practically a vault.