Generate JWT Secrets & Key Pairs
Create secure secrets and cryptographic key pairs for signing JWTs. Generate HS256 secrets, RSA, or ECDSA keys in PEM format instantly for use in your authentication setup.
Key Type Guide
- HMAC: Use HS256, HS384, or HS512 algorithms. Same key for signing and verification.
- RSA: Use RS256, RS384, or RS512. Private key signs, public key verifies.
- ECDSA: Use ES256, ES384, or ES512. Smaller keys, faster than RSA.
How the JWT Secret Key Generator Works
This tool generates cryptographically secure keys for signing and verifying JSON Web Tokens. It supports three key types: HMAC (symmetric), RSA (asymmetric), and ECDSA (elliptic curve), each with different security characteristics.
Key Generation Process
- Select the key type: HMAC for simple setups, RSA or ECDSA for asymmetric signing
- For HMAC, choose the key size: 256-bit, 384-bit, or 512-bit
- Click "Generate Key" to create a cryptographically random key
- For RSA/ECDSA, a public/private key pair is generated using the Web Crypto API
- Keys are formatted in PEM format for easy copy-paste into configuration files
- Copy the generated key(s) and store them securely in your application
Specific Use Cases
Setting Up New Authentication System
A developer building a new API needs a secure secret for JWT signing. They generate a 256-bit HMAC key and configure it in their authentication middleware environment variables.
Migrating to Asymmetric Keys
A team moving from monolithic to microservices architecture needs separate signing and verification keys. They generate an RSA key pair - private key stays with the auth service, public key is distributed to other services.
Key Rotation Preparation
Following security best practices, an engineer generates new keys quarterly. They use this tool to create replacement keys before the old ones expire.
Development Environment Setup
A developer setting up a local development environment needs test keys that match production key types. They generate keys of the same type but different values for safe local testing.
ECDSA for Mobile/Embedded Applications
A mobile team chooses ECDSA keys for their smaller size and faster verification. The shorter keys reduce bandwidth and improve performance on resource-constrained devices.
What to Know Before Using This Tool
Understanding key types and security considerations:
- HMAC keys are symmetric - the same key signs and verifies tokens
- RSA and ECDSA are asymmetric - private key signs, public key verifies
- 256-bit HMAC (HS256) is secure for most applications
- RSA keys are larger but widely supported across all platforms
- ECDSA keys are smaller and faster but require newer library support
- Keys are generated using browser's crypto.getRandomValues() - cryptographically secure
- Store private keys securely - never commit them to version control
- PEM format includes BEGIN/END markers for easy identification
Frequently Asked Questions
Which key type should I choose?
For simple single-service applications, HMAC (HS256) is easiest. For microservices or when you need to distribute verification capability without signing capability, use RSA (RS256) or ECDSA (ES256).
How long should my HMAC secret be?
Match the key size to your algorithm: 256 bits for HS256, 384 bits for HS384, 512 bits for HS512. Longer keys provide more security but the algorithm strength is the limiting factor.
What's the difference between public and private keys?
The private key signs tokens and must be kept secret. The public key verifies tokens and can be shared. Never share your private key - if it's compromised, attackers can forge tokens.
Can I use the same key for multiple applications?
It's better to use separate keys for each application. If one key is compromised, only that application is affected. Use descriptive names in your key management to track which key belongs to which service.
How often should I rotate JWT keys?
Security best practices suggest rotating keys every 90 days, or immediately if you suspect compromise. Plan your rotation strategy - with asymmetric keys, you can publish new public keys before retiring old ones.
Why are RSA/ECDSA keys so much longer than HMAC keys?
Asymmetric cryptography requires larger keys for equivalent security. A 256-bit ECDSA key provides similar security to a 3072-bit RSA key. HMAC can use shorter keys because it's symmetric cryptography.
Other Free Tools
JWT Decoder & Validator
Decode & Validate JWT Tokens Instantly
JWT Generator & Signer
Generate & Sign Custom JWT Tokens
JWT Debugger & Tester
Debug & Test JWT Tokens Step-by-Step
JWT Claim Extractor & Formatter
Extract & Format JWT Claims
JWT Expiry Checker & Timestamp Converter
Check JWT Expiry & Convert Timestamps
ASCII to Hex Converter
ASCII to Hex Converter: Text to Hexadecimal Translator
Barcode Generator
Free Barcode Generator
Binary to Text Converter
Binary to Text Converter
Free Printable Calendar Maker
Create & Print Your Custom Calendar
Pie Chart Maker
Free Pie Chart Maker Online