The ROT-13 encoder encrypts text entered via the ROT-13 encryption. The tool replaces a letter with the letter 13 letters after it in the Latin alphabet. With the same tool a ROT-13 encoded text can be decrypted into the original plaintext. ROT-13 is considered to be an unsafe and weak form of encryption. ROT-13 is a so-called Caesar cipher. The abbreviation comes means "rotate by 13 places".