How to use the RSA Key Pair Generator
- 1. Choose size and usePick a key size and whether it is for encryption or signatures.
- 2. GenerateYour browser creates the key pair and runs a quick self-test.
- 3. Save the keysDownload public.pem to share and private.pem to keep safe.
How RSA keys work
RSA uses a pair of mathematically linked keys. The public key can be shared with anyone: they use it to encrypt messages to you or to verify your signatures. The private key stays secret and is used to decrypt or sign. Security rests on how hard it is to factor the product of two large primes.
With the default settings the tool creates a 2048-bit RSA key for RSA-OAEP encryption with SHA-256 and the standard public exponent 65537. The public key is exported in SPKI format (it begins -----BEGIN PUBLIC KEY-----) and the private key in unencrypted PKCS#8 (-----BEGIN PRIVATE KEY-----). A self-test encrypts and decrypts, or signs and verifies, a short message to prove the pair works.
Choosing settings and keeping keys safe
- 2048 bits is the common minimum today; 3072 bits matches 128-bit security; 4096 is slower with a modest gain.
- RSA-OAEP is for encryption; RSA-PSS is the modern signature scheme; PKCS#1 v1.5 signatures remain widely supported, for example in JWT RS256.
- Protect the private key. Anyone who has it can decrypt your data or sign as you.
- SSH keys use a different file format, and many teams now prefer Ed25519 for SSH.
Keys are generated by the Web Crypto API inside your browser and are never sent anywhere. For production servers, generate keys on the machine that will use them (for example with OpenSSL) and store them in a key vault or with a passphrase. Use these keys for learning, testing and development. Inspect certificates that contain public keys with the SSL certificate decoder, or try symmetric encryption in the AES text tool.
Frequently asked questions
Can I use these keys for SSH?
Not directly. SSH expects its own key format; generate SSH keys with ssh-keygen instead.
Why does 4096 bits take longer?
Finding two large primes takes more work as size grows; a few seconds is normal on phones.
Is the RSA Key Pair Generator free?
Yes, the RSA Key Pair Generator is free. The first time you generate your first key pair, you are asked for your name and WhatsApp number once. After that, this and every other Uncodemy tool opens straight away without the form.