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ROT13 Cipher & Caesar Cipher - Text Encryption Tool

ROT13 Cipher & Caesar Cipher

Encode or decode text using ROT13 or Caesar cipher. ROT13 replaces each letter with the letter 13 positions after it in the alphabet. Caesar cipher allows you to select a custom shift amount.

Cipher Options

ROT13 Standard 13-letter shift cipher

Caesar Cipher Custom letter shift amount

Shift Amount: Number of positions to shift (1-25)

Advanced Options

Preserve Case Keep uppercase and lowercase letters

Keep Numbers Unchanged Don't encrypt numeric digits

Keep Symbols Unchanged Don't encrypt punctuation and special characters

Preserve Formatting Keep spaces and line breaks

Input Text

Processed Text

Quick Examples

What is ROT13?

ROT13 ('rotate by 13 places') is a simple letter substitution cipher that replaces each letter with the 13th letter after it in the alphabet. A becomes N, B becomes O, and so on. Since there are 26 letters in the English alphabet, applying ROT13 twice returns the original text - it essentially encrypts and decrypts itself.

Despite its simplicity, ROT13 has been widely used in online forums as a means of hiding spoilers, punchlines, puzzle solutions, and offensive material from casual glance. It's not intended as serious cryptography, since it provides virtually no security against anyone who recognizes it, but it serves as a convenient form of light obfuscation.

What is a Caesar Cipher?

The Caesar cipher, named after Julius Caesar who reportedly used it for military communications, is one of the simplest and oldest encryption techniques. It works by shifting each letter in the plaintext a certain number of places down the alphabet. For example, with a shift of 3, A would be replaced by D, B would become E, and so on.

ROT13 is actually a special case of the Caesar cipher with a shift of 13. Unlike general Caesar ciphers, ROT13 is self-reciprocal, meaning the same operation works for encoding and decoding. With other shift values in the Caesar cipher, you need to apply the reverse shift (26 minus the original shift) to decode.

Características:

Two Cipher Methods: Choose between standard ROT13 and Caesar cipher with custom shift
Case Preservation: Option to maintain the original case of letters
Selective Encryption: Choose whether to encrypt numbers and symbols or leave them unchanged
Format Retention: Preserve your original spaces, line breaks, and text layout
Instant Processing: See your encoded or decoded text immediately
Example Presets: Try out various examples with a single click
Easy Sharing: Copy or download your processed text for use anywhere

Uses for ROT13 and Caesar Ciphers

Spoiler Protection: Hide spoilers for books, movies, or TV shows
Puzzle Creation: Make simple puzzles or riddles for friends or students
Educational Tool: Demonstrate basic encryption concepts
Light Privacy: Hide text from casual observation
Fun Communications: Send playful encoded messages to friends
Historical Interest: Experience one of the oldest known encryption methods

Cómo Usar:

Select either ROT13 or Caesar Cipher as your encryption method
If using Caesar Cipher, choose your desired shift amount (1-25)
Adjust the advanced options to your preferences
Enter or paste the text you want to encode or decode
Click 'Encode/Decode Text' to process your text
Copy or download the result

Interesting Fact

ROT13 is a special case of the Caesar cipher because applying it twice returns the original text. This is because shifting 13 places and then shifting another 13 places brings you back to the starting point (13 + 13 = 26, which is the length of the English alphabet).