Timestamp Signature Generator
Generate HMAC signatures with timestamps for API authentication. Create secure request signatures for API verification.
About Timestamp Signature Generator
Our free online Timestamp Signature Generator is a powerful tool that creates HMAC (Hash-based Message Authentication Code) signatures combined with timestamps for API authentication. It supports three widely-used HMAC algorithms: HMAC-MD5, HMAC-SHA1, and HMAC-SHA256, allowing you to generate secure request signatures.
Timestamp-based signatures are commonly used in API authentication to prevent replay attacks. By including a timestamp in the signed data, the server can verify that the request was generated within an acceptable time window, making it much harder for attackers to reuse intercepted requests.
This tool processes your input entirely in the browser using CryptoJS, ensuring your secret keys and data never leave your device. Generate HMAC signatures with timestamps instantly for testing APIs, debugging authentication issues, or building integration workflows.
The auto-generate feature updates the signature in real-time as you type, making it convenient for quick signature generation. The output includes both the raw signature and a formatted summary with the timestamp, data, and algorithm used.
Features
Fast Generation
Generate HMAC signatures instantly with no registration or limits. Completely free to use.
Auto-Generate
Automatically update the signature as you type for real-time signature generation.
Timestamp Integration
Include Unix timestamps in your signatures to prevent replay attacks in API authentication.
Multiple Algorithms
Support HMAC-MD5, HMAC-SHA1, and HMAC-SHA256 for different security requirements.
One-Click Copy
Copy the generated signature to clipboard with a single click for easy integration.
Privacy First
All processing happens in your browser. Your secret keys never leave your device.
How to Use
Enter Secret Key
Type or paste your secret API key into the Secret Key input field.
Enter Data / Message
Enter the data or message you want to sign with the HMAC algorithm.
Select Algorithm
Choose between HMAC-MD5, HMAC-SHA1, and HMAC-SHA256 based on your API requirements.
Generate and Copy
Click Generate Signature or enable auto-generate, then copy the signature for use in your API requests.
Frequently Asked Questions
What is HMAC?
HMAC (Hash-based Message Authentication Code) is a specific type of message authentication code that combines a cryptographic hash function with a secret key. It provides both data integrity and authentication, ensuring that a message has not been tampered with and was generated by someone with the secret key.
Why use timestamps with HMAC signatures?
Including a timestamp in HMAC signatures prevents replay attacks, where an attacker intercepts and resends a valid request. By verifying that the timestamp is within an acceptable time window, the server can reject old or replayed requests.
Which HMAC algorithm should I use?
HMAC-SHA256 is recommended for most applications as it provides strong security with good performance. HMAC-SHA1 is still widely used but being phased out in favor of SHA256. HMAC-MD5 should only be used for legacy compatibility as MD5 has known vulnerabilities.
How is the signature generated?
The tool captures the current Unix timestamp (in milliseconds), then computes an HMAC of the data/message using your secret key. The output includes the timestamp, original data, algorithm used, and the resulting HMAC signature in hexadecimal format.
Is this timestamp signature generator free?
Yes, it is completely free to use with no registration, sign-up, or limits. You can use it as many times as you need for personal, educational, or commercial projects.
Does it work offline?
Yes, once the page is loaded, all HMAC signature generation happens entirely in your browser using JavaScript. No server communication is needed, so you can use it even without an internet connection after the initial page load.