ROT13 with Material Design. ROT13 or Rotate by 13 jumps is a simple letter substitution cipher that replaces the letter 13 letters after it in the alphabet. Inside this app, you are able to: 1) Covert plain text to ROT13. 2) Copy ROT13. 3) Paste from previously copied. 4) Delete all text. New feature. Ability to change the number of rotations instead of the standard 13.