Speck Encrypt & Decrypt
Encrypt or decrypt text with the Speck128 block cipher (128, 192 or 256-bit key) in ECB or CBC mode, with base64 or hex output. Runs in your browser.
Input
Output
More ways to use this tool
REST API
curl -X POST https://api.iotools.cloud/v1/tool/speck-encrypt-decrypt \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"inputText": "Hello, World!",
"direction": "encrypt",
"key": "000102030405060708090a0b0c0d0e0f",
"keyFormat": "hex",
"mode": "ecb",
"iv": "",
"format": "hex"
}'Swap in your own key from your account. The tool's fields are the body — no wrapper.
Ask an AI agent
Use the IOTools `speck-encrypt-decrypt` tool (Speck Encrypt & Decrypt) on this input:
YOUR_INPUT_HEREPaste this at any agent connected to the IOTools MCP server, then add your input.
Embed widget
<iframe
src="https://iotools.cloud/embed/speck-encrypt-decrypt/"
width="100%" height="520" frameborder="0" scrolling="no" loading="lazy"
title="Speck Encrypt & Decrypt — iotools.cloud"
sandbox="allow-scripts allow-forms allow-same-origin allow-downloads allow-popups allow-popups-to-escape-sandbox"
allow="clipboard-write"
style="width:100%;border:1px solid #e5e7eb;border-radius:12px;overflow:hidden"></iframe>
<script src="https://iotools.cloud/embed.js" async></script>Drop this into your own page — free, no key required, just a link back.
| Cost per API/MCP call | From 5 credits |
|---|---|
| Need more credits? | View pricing |
Also available with
Guides
Encrypt or decrypt text with the Speck128 block cipher entirely in your browser. Nothing you type, including the key, is uploaded.
How to use it
- Paste your text (or the ciphertext, when decrypting) into Input.
- Pick Encrypt or Decrypt.
- Enter the Key: 16, 24 or 32 bytes (Speck128/128, /192 or /256), as Hex or Text.
- Choose ECB or CBC. CBC needs a 16-byte IV as 32 hex characters.
- Choose whether ciphertext is Base64 or Hex.
Compatibility
Words are 64-bit little-endian, as in the NSA reference implementation, so the published Speck128/128 test vector reproduces exactly. Plaintext is padded with PKCS#7 to a multiple of 16 bytes.
Should I use it?
Speck is a lightweight cipher designed for constrained devices. It has no integrity check and ECB leaks patterns, so use it only to interoperate with existing systems. For anything new, use AES.
Troubleshooting
- "Decryption failed": key, IV or mode differs from encryption, or the ciphertext was changed.
- Different output elsewhere: check byte order and padding conventions of the other tool.