RSA key generator.

2048 bits is the minimum accepted today and fine until about 2030; 3072 matches 128-bit security and is NIST's advice beyond that; 4096 is slower to generate and use for a modest gain. For new systems an EC key (P-256 or Ed25519) is smaller and faster at equal strength.

PKCS#8 (BEGIN PRIVATE KEY) and SPKI (BEGIN PUBLIC KEY) are the generic forms most libraries read. PKCS#1 (BEGIN RSA PRIVATE KEY) is the older RSA-only form OpenSSL wrote for years. JWK is the JSON form JWT libraries and JWKS endpoints use.

A hash of the public key that names it in a sentence: the SHA-256 of the SPKI bytes, as certificate pinning uses, and the JWK thumbprint (RFC 7638), the usual kid of a JWK.

The browser's Web Crypto API makes the keys with its own cryptographic random generator, the same code that runs TLS. The private key is created in this page's memory and exists nowhere else.

Pick the algorithm and the size or curve and press Generate. The private and public keys appear as PEM and JWK, with their fingerprints, each with copy and download.

Ed25519 needs a recent browser: Chrome 137, Safari 17 and Firefox 129 or later. Where it is missing, the tool says so and RSA and ECDSA still work.

No. Generation and export run in your browser and the page makes no request; close the tab and the keys are gone. Save the private key somewhere safe before you leave.

No. The RSA key generator is free and opens without a sign-in, an account or an install.

Nothing. The RSA key generator holds your input in the page's memory, so closing or reloading the tab clears it, and it saves nothing in this browser.

Closest to the RSA key generator: SSH key generator, JWT encoder, Certificate decoder, JWT decoder. Each opens on its own page, free and in the browser.

The RSA key generator is one of 20 in its group. The group's page, /tools/security, lists them all.

The tool is free. Its interface is built from shadcn.io's own components (Button, Input, Slider and the rest of the registry under /ui), which come in React, Vue, Svelte and Solid. Pro adds the blocks and templates for the product around it.