RSA key generator — create a keypair on-device
Generate a 2048- or 4096-bit RSA keypair in PEM format. It runs entirely in your browser using Web Crypto (0 uploads, works offline), so your private key is created on your device and never sent anywhere.
How to use it
- Choose the key size.
- The public and private keys are generated on your device.
- Copy or Download each PEM file.
FAQ
How do I generate an RSA keypair for free?
Pick a key size and this page generates the pair with your browser's Web Crypto, exporting both keys in standard PEM format — on your device with no upload.
Is the private key sent anywhere?
No. The keypair is generated entirely in your browser and neither key is transmitted or stored, which you can verify by turning off your Wi-Fi. A private key generated on a server you do not control is compromised from the start.
Which key size should I choose?
2048-bit is the common default and is fast to generate. 4096-bit is stronger but slower; choose it when a policy or long-term use warrants the extra margin.
What can I use the keys for?
The keys are RSA-OAEP, suitable for encryption. Store the private key securely and share only the public key.
Limits
Generates RSA-OAEP encryption keys in PEM; it does not create signing certificates or manage key storage.
Related
The AES tool does password-based symmetric encryption; the file checksum verifier checks integrity.
Bookmark this page (Ctrl+D, or ⌘D on Mac) or install the app — it works offline the next time you need it.