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HMAC Generator - SHA256, SHA-1, MD5
Free online HMAC generator supporting SHA-256, SHA-1 and MD5 hash algorithms. Create message authentication codes for API verification, JWT signing and data integrity checks.
How to Use HMAC Generator
Quick Start Guide
1
Enter your secret key - this is shared between sender and receiver to verify authenticity
2
Type or paste the message you want to authenticate in the input area
3
Select the hash algorithm - SHA-256 is recommended for most applications
4
Click Generate to create the HMAC code, which can be used to verify the message has not been tampered with
Frequently Asked Questions
HMAC (Hash-based Message Authentication Code) combines a secret key with a hash function like SHA-256 to produce a code that verifies both the authenticity and integrity of a message. Only someone with the same secret key can generate the same HMAC for a given message.
HMAC is used to verify that a message has not been tampered with and comes from a trusted sender. Common applications include API authentication (AWS uses HMAC for signing requests), JWT token signing, and verifying file integrity during transmission.
SHA-256 offers the best balance of security and performance for most applications. SHA-512 provides slightly higher security. MD5 and SHA-1 should only be used for compatibility with legacy systems - they have known cryptographic weaknesses for collision resistance.
No. This tool runs entirely in your browser. Your secret key and message data never leave your device. All HMAC computation happens locally.
Still have questions? Check out our other tools or contact us for support.