Skip to main content
Castov
DEVELOPER

CyberChef & Magic Decoder

The Swiss Army Knife for developers, security analysts, and CTF players. Automatically detect obscure data encodings, chain transformation recipes, and analyze entropy entirely in your browser.

Presets:
104 characters (104 bytes)Shannon Entropy: 5.168 / 8.0
Magic Format Auto-Detected
Base64 Stringhigh confidence

Decodes cleanly into printable text: "Hello, Cyber World! This is a private he..."

Recipe Pipeline

1 Active
1Base64 DecodeEncoding
Preview: Hello, Cyber World! This is a private hexadecimal message de0.11ms
Output: 78 chars (78 bytes)Executed in 0.14ms

Modern Client-Side CyberChef & Universal Decoder

Developers, reverse engineers, and security analysts frequently encounter obscure encoded payloads, obfuscated malware scripts, JWT tokens, and multi-layered data transforms. Manually navigating multiple websites or running command-line scripts introduces friction and potential privacy leaks.

Castov CyberChef brings the versatility of a Swiss Army Knife directly into the browser with zero server uploads, lightning-fast execution, and automatic format detection.

Multi-Step Transformation Recipes & Entropy Inspection

Real-world security investigations often require combining multiple decoders in sequence. For example, malicious payloads may be hex-encoded, then compressed, and then Base64-encoded. Our recipe pipeline allows you to chain operations effortlessly, inspect intermediate step previews, and toggle steps on and off with zero latency.

Integrated Shannon entropy calculation immediately reveals whether an unknown payload is plain text, Base64 obfuscated, or strongly encrypted.

How to use this tool

  1. Paste or upload any encoded string, cipher text, token, or raw byte stream into the input pane.
  2. Review the Magic Inspector recommendations or browse operations to construct your transformation pipeline.
  3. Reorder, configure parameters, or toggle individual steps to observe live decoded output in real time.
  4. Inspect Shannon entropy, hex dump offsets, or copy and share the reproducible recipe link.

Examples

Real-world data decoding, cryptographic analysis, and transformation recipes.

Base64 & Hex Stream Decoding

43 61 73 74 6f 76 (Hexadecimal bytes)

Decoded String
Castov
Detected Format
Hexadecimal byte stream
Entropy
2.585 (Standard text)

ROT13 Cipher Deobfuscation

Pnfgbi qrpbqre vf snfg naq 100% pyvrag-fvqr.

Decoded Plaintext
Castov decoder is fast and 100% client-side.
Method
Caesar ROT13 shift (+13)

JWT Token Claims Inspection

eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiJ1c2VyXzEiLCJleHAiOjE4MDAwMDAwMDB9.sig

Algorithm
HS256
Subject
user_1
Status
Valid (Unexpired)

Frequently Asked Questions

Is my data or secret key sent to any remote server?
No, every operation, cipher, and hash executes 100% locally in your web browser using client-side Web Crypto and JavaScript. Zero network requests are sent.
What formats can the Magic Inspector auto-detect?
It automatically identifies JWT tokens, Base64 strings, Hex byte streams, URL percent-encoding, HTML entities, 8-bit binary streams, Morse code, JSON structures, and standard cryptographic hashes (MD5, SHA-1, SHA-256).
How does the recipe pipeline work?
You can chain multiple transformation steps together in sequence, such as Base64 decoding followed by URL decoding and JSON formatting. Each step can be reordered, fine-tuned, or toggled on and off.
What does the Shannon Entropy score indicate?
Entropy measures the randomness of the input data on a scale from 0 to 8. Scores above 7.2 typically indicate encrypted payloads or compressed archives, while scores below 4.5 indicate standard natural language or structured code.
Can I share my custom recipe and input with my team?
Yes, click the Share Recipe button to generate a permalink with your entire pipeline encoded directly into the URL hash.

Related tools