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RSA Key Pair Generator

Generate RSA key pairs in PEM format

Runs in your browserUtility03 — Encoding & Crypto

What is RSA Key Pair Generator?

This RSA key pair generator uses the browser Web Crypto API to create 2048-, 3072-, or 4096-bit keys and outputs PEM text for the SPKI public key and the PKCS#8 private key, with a choice between signing and encryption usage. Generation happens locally and the private key is never uploaded.

How to use RSA Key Pair Generator

  1. 1Choose a key size — 2048 bits is the current practical minimum.
  2. 2Choose a purpose: signing and verification (RSASSA-PKCS1-v1_5) or encryption (RSA-OAEP).
  3. 3Click "Generate key pair"; it finishes within a few seconds.
  4. 4Copy and store the public and private keys separately, keeping the private key protected.

How do I do this in code?

Use the tool above for one-off work; for anything you repeat, move it into a script or your project.

# Generate a private key
openssl genpkey -algorithm RSA -pkeyopt rsa_keygen_bits:2048 -out private.pem

# Derive the public key from it
openssl rsa -in private.pem -pubout -out public.pem

Frequently asked questions

Is it safe to generate RSA keys in a browser?+

The generation itself uses the browser cryptographic random source and its vetted algorithm implementation, and the key never leaves the page. That said, production keys should be generated on a controlled host and moved straight into a key management system, so they never pass through a clipboard or a chat window. This tool is meant for testing and debugging.

Is 2048-bit RSA still strong enough?+

It remains the mainstream minimum and the baseline most compliance regimes require. If the key needs a long service life — say beyond five years — go straight to 3072 bits. When you want strength without the performance cost, elliptic curve keys (Ed25519 or P-256) are the more modern choice.

Can I use one key pair for both signing and encryption?+

You should not. The two purposes use different padding schemes (PKCS#1 v1.5 versus OAEP), sharing a key weakens security, and in some protocols it opens up additional attack surface. Generating separate keys per purpose, as this tool does, is the correct approach.

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