🔐 HMAC Generator (WebCrypto)
Professional HMAC (Hash-based Message Authentication Code) generator using native WebCrypto API. Supports SHA-256/384/512 algorithms with hex and base64 output formats. Perfect for API authentication, message integrity verification, and secure token generation.
HMAC Results:
HMAC-SHA256 Authentication Code
Secure message authentication using WebCrypto
📝 Input Parameters
🔐 HMAC Authentication Code
🔒 Security Information
Industry Standard
Cryptographically Secure
Key Never Transmitted
💡 Security Best Practices:
Use strong, unique secret keys. Store keys securely. Use HMAC-SHA256 minimum for production systems. Rotate keys regularly.
How to Use This HMAC Generator (WebCrypto)
How to Generate HMAC:
- Enter your input data (message to authenticate)
- Provide a strong secret key (minimum 8 characters)
- Select your preferred HMAC algorithm (SHA-256 recommended)
- Choose output format (hex for readability, base64 for APIs)
- Click "Generate HMAC" to create the authentication code
- Copy the result or download as a file for your records
Security Best Practices: Use unique, strong secret keys for each application. Store keys securely and rotate them regularly. Never expose secret keys in client-side code for production systems.
How It Works
Understanding HMAC (Hash-based Message Authentication Code):
HMAC combines cryptographic hashing with secret key authentication to provide both data integrity and authenticity verification:
- Key Preparation: The secret key is processed and padded to match the hash function's block size
- Inner Hash: Key is XORed with inner pad (0x36), concatenated with message, then hashed
- Outer Hash: Key is XORed with outer pad (0x5C), concatenated with inner hash result, then hashed again
- Final Output: The result is a fixed-size authentication code unique to the key and message
WebCrypto Implementation:
- Security: Uses native browser cryptography APIs for secure computation
- Privacy: All operations performed locally - data never transmitted
- Standards: Follows RFC 2104 specification for maximum compatibility
- Performance: Optimized native implementation provides fast generation
When You Might Need This
- • API authentication and request signing for secure web services
- • Message integrity verification for data transmission
- • JWT token signing and validation for authentication systems
- • Webhook payload verification to ensure data hasn't been tampered
- • Password-based authentication with secure key derivation
- • Digital signature creation for document authenticity
- • Blockchain transaction verification and validation
- • Secure session management and cookie signing
- • File integrity checking and checksum generation
- • Database record authentication and tamper detection
Frequently Asked Questions
What is HMAC and why should I use it?
HMAC (Hash-based Message Authentication Code) is a cryptographic technique that combines a secret key with a hash function to provide both data integrity and authentication. It ensures that a message hasn't been altered and confirms the sender's identity. Unlike simple hashing, HMAC requires a secret key, making it secure against tampering and forgery attacks.
Which HMAC algorithm should I choose for my application?
HMAC-SHA256 is recommended for most applications as it provides excellent security with good performance. Use HMAC-SHA384 for higher security requirements, and HMAC-SHA512 for maximum security in sensitive applications like financial systems or government use. All three are currently considered cryptographically secure by security standards.
Is it safe to generate HMAC client-side in the browser?
Yes, using the WebCrypto API for HMAC generation is safe because the cryptographic operations happen locally in your browser. Your secret key and data never leave your device. However, be careful about where you use the generated HMAC - don't expose secret keys in client-side code for production applications.
Can I verify HMAC generated by this tool in other systems?
Absolutely! HMAC is a standardized algorithm (RFC 2104) that produces identical results across different implementations when using the same input data, secret key, and hash algorithm. You can verify these HMACs in any programming language or system that supports HMAC generation.
What's the difference between hex and base64 output formats?
Hex (hexadecimal) represents the HMAC as a string of characters 0-9 and a-f, making it longer but more readable. Base64 encoding produces a shorter string using A-Z, a-z, 0-9, +, and / characters. Base64 is more compact and commonly used in web APIs, while hex is often preferred for debugging and human readability.