RSA Key Pair Generator
Generate an RSA key pair in your browser and export it as PKCS#8 / SPKI PEM or JWK. The private key never leaves the page.
Private key
Public key
Key pairs generated on your device
The pair is generated with `crypto.subtle.generateKey` and exported here directly. There is no request to a server, which is the only acceptable arrangement for a private key — a key that was ever transmitted to generate it is a key you cannot trust.
Nothing is stored either. Close the tab and the private key is gone, so copy it before you navigate away.
- PEM — the `-----BEGIN PRIVATE KEY-----` form, PKCS#8 for the private half and SPKI for the public half. This is what OpenSSL, nginx and most libraries expect.
- JWK — the JSON form used by JOSE, OIDC and Web Crypto itself. This is what a `/.well-known/jwks.json` endpoint serves.
RSA or elliptic curve
An ECDSA P-256 key gives roughly the security of a 3072-bit RSA key, in about a tenth of the size, and signs far faster. Prefer it for anything new.
RSA remains the safer bet for interoperability: some older systems, hardware modules and enterprise PKI still accept nothing else.
Frequently asked questions
Are these keys really generated locally?
Yes. The page makes no network requests at all — you can disconnect and generate a pair. That is verifiable in your browser's network panel.
What key size should I use?
RSA 2048 is the current minimum and is fine for most uses; 3072 or 4096 for keys with a long life. For elliptic curve, P-256 unless something specifies otherwise.
Why does my server reject the private key?
It probably wants PKCS#1 ("BEGIN RSA PRIVATE KEY") rather than the PKCS#8 exported here. Convert with: openssl pkcs8 -topk8 -nocrypt -in pkcs8.pem -out pkcs1.pem
Should I use this for a production key?
For test and development keys, and for JWT signing keys you will store in a secret manager, yes. For a CA or an HSM-backed key, generate it where it will live instead.