UD5 Toolkit
Atbash Cipher – Reverse Alphabet Encryption
Apply the ancient Atbash cipher (A→Z, B→Y) to any text. Since it's self‑inverse, encoding and decoding use the same function. Fun for code puzzles.
Tag: Cipher Tools - Encrypt & Decrypt
8+ toolsPolybius Square Cipher Tool – Online Encode & Decode
Encrypt or decrypt text using the classical 5x5 Polybius square. Excludes J or merges I/J.
Letter Frequency Analyzer - Online ETAOIN SHRDLU
Paste text to see a live letter frequency bar chart. Helps break substitution ciphers. All local analysis.
ROT13 Encoder & Decoder - Online Caesar Cipher ROT13
Easily apply ROT13 cipher to obfuscate or reveal text. A classic letter substitution cipher that works bidirectionally. Purely client-side processing.
SSL Cipher Suite Checker - Online Test TLS Security
Check which cipher suites a website supports and identify weak or outdated ones. Quick security audit from your browser.
Pigpen Cipher Encoder - Online Masonic Symbol Translator
Encrypt text into the classic pigpen symbols and decode them back. Fun for treasure hunts and mystery games.
Emoji Cipher Decoder - Online Secret Message Fun
Decode a message hidden in a string of emojis (each emoji maps to a letter). Fun game for kids. Create your own.
Text to Emoji Cipher - Online Encode Secret Messages
Convert your text into a string of emojis using a simple substitution cipher. Share secret messages that look fun. Decode them with the same tool. All local.