Generate the key pair
Select Generate Key Pair. A fresh public and private key appears, generated in your browser.
Generate RSA Key Pair Online Free
Create an RSA public and private key pair in your browser, export both as PEM, import keys you already have, and encrypt or decrypt text without sending a single key to a server.
Algorithm:
Public Key
Private Key
Three simple steps
How to Generate an RSA Key Pair Online
A fresh pair in one click, generated entirely on your device.
Save the keys
Export the private key and the public key as PEM files, or copy them into a password manager or a configuration file.
Encrypt and decrypt
Type a message and select Encrypt to protect it with the public key, then select Decrypt to read it back with the private key.
Public and private keys
What Each Key Is For
Two keys, two jobs, and only one of them should ever be shared.
| Key | Used for | Share it? |
|---|---|---|
| Public key | Encrypting a message that only the private key holder can read | Yes, freely |
| Private key | Decrypting messages and proving ownership of the pair | Never |
| PEM export | Saving either key as a text file for servers, clients and libraries | Only the public key |
Message size limit: RSA can only encrypt data shorter than the key size minus the padding overhead. For larger data, encrypt the content with a symmetric key and use RSA to protect that key instead.
Free RSA tool
Keys That Never Touch a Server
A comfortable way to try asymmetric encryption without installing anything.
One click key pair
Generate a matching public and private key without opening a terminal or installing a library.
PEM export
Save each key as a PEM file you can drop into a server configuration or a deployment secret.
Import your own keys
Paste an existing key pair in PEM format and use it for the encryption and decryption on this page.
Local by default
Generation and encryption run in your browser, so no key and no plaintext is uploaded anywhere.
Questions and answers
RSA Key Generator FAQ
Are my keys uploaded to a server?
No. Key generation, encryption and decryption run with JavaScript in your browser. Private keys never leave your device and 73hi stores nothing.
Can I import keys I already have?
Yes. Select Import Keys, paste the public and private key in PEM format and load them to use the pair on this page.
What is the difference between the public and the private key?
The public key encrypts and can be shared freely. The private key decrypts and must stay secret, because anyone holding it can read the messages.
Why is there a message length limit?
RSA can only encrypt data shorter than the key size minus the padding overhead. Real systems encrypt the data with a symmetric key and use RSA only to protect that key, which is the recommended pattern for anything larger than a short message.
Is this suitable for production systems?
Use it for testing, learning and one-off messages. Production systems should generate keys with a vetted library such as OpenSSL and follow current key size and padding recommendations.
Does the page work on mobile?
Yes. Key generation and encryption work in any modern mobile browser, although it is easier to copy long PEM blocks on a desktop.