What is RSA?
An RSA key generator creates a public/private key pair for the RSA algorithm. RSA is asymmetric: the public key encrypts data and verifies signatures, while the private key decrypts and signs. Its security rests on the difficulty of factoring the product of two large prime numbers. For production use at least 2048-bit keys (4096-bit for long-lived keys). Keys are generated locally in your browser and are never transmitted.
Private by design: your RSA keys are generated in your browser and never uploaded. Keep your private key secret and back it up safely.
How RSA works
RSA key generation builds a linked key pair from prime numbers:
- Pick two large random primes and multiply them to get the modulus n.
- Choose a public exponent e (commonly 65537).
- Compute the private exponent d from e and the totient of n.
- The public key is (n, e); the private key is (n, d).
How to use
- Choose your key options (curve/size, format).
- Click generate to create the key pair locally.
- Save your private key somewhere safe and never share it.
Options explained
- Key size — 2048-bit minimum for production; 4096-bit for long-lived or high-security keys.
- Output format — Export keys in PEM (and other) formats.
- Passphrase — Optionally encrypt the private key with a passphrase.
Common uses
- TLS/SSL certificates and HTTPS.
- SSH authentication keys.
- Signing software, documents and JWTs.
- Encrypting symmetric keys for secure exchange.
Frequently asked questions
What key size should I use?
At least 2048 bits; use 4096 bits for keys that must last many years.
Which key do I share?
Share the public key; never share the private key.
Are the keys generated privately?
Yes, entirely in your browser — nothing is sent to a server.