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RSA Key Pair Generator

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Not for production use. This is for learning and testing. Generate real production keys with a dedicated offline tool (e.g. openssl) in a reviewed environment. 100% generated in your browser — nothing is ever transmitted.

Generate an RSA public/private key pair entirely in your browser, in PEM format — only 2048-bit and up, no weak key sizes offered.

How it works

  1. Pick a key size (2048, 3072, or 4096-bit)
  2. Click "Generate key pair" — larger sizes take a few seconds
  3. Copy or download the public key (SPKI) and private key (PKCS#8), both in PEM format

Frequently asked questions

Can I use this for a real production service?

Not recommended. Use this for learning and testing; generate production keys with a dedicated offline tool like openssl in a reviewed environment.

Is the key sent to a server?

No — generation runs through crypto.subtle.generateKey entirely in your browser. Nothing is ever transmitted.

Why can't I pick 512-bit or 1024-bit keys?

Those sizes are no longer secure — 512-bit RSA has actually been broken in practice. This tool only offers 2048-bit and above, matching NIST's recommended minimum.

#RsaKeyPairGenerator#RsaKeyGeneratorClientSidePem#RsaKeyGeneratorNoWeakSizes#RsaKeyGeneratorNotForProductionWarning

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From the blog

A popular RSA key generator lets you pick 512-bit — a size that's actually been cracked in the real world. Ours doesn't offer it.
dev

A popular RSA key generator lets you pick 512-bit — a size that's actually been cracked in the real world. Ours doesn't offer it.

We checked two RSA key generators directly: one never warns against using its keys in production, the other offers 512-bit RSA with no caveat at all, despite it being publicly broken. Ours starts at 2048-bit, the NIST-recommended minimum, and says plainly what these keys are and aren't for.

2026-08-29

Update history

  • 2026-08-30 Added: a cover image — used as the card thumbnail, social share image, and blog title image.
  • 2026-08-29 Launched: client-side RSA key pair generation (2048/3072/4096-bit only, no weak sizes offered) via Web Crypto API, PEM output for both keys, explicit not-for-production warning.