RSA Encryption
Generate an RSA key pair, encrypt a short text with the public key and decrypt it with the private key — good for sending a password or one-time code.
How to use the RSA encryption tool
- Click "Generate new key pair" — you get a public key and a private key.
- Give the public key to whoever will send you a message (it does not need to stay secret). Keep the private key to yourself.
- They paste your public key and their message into the "Encrypt" box, click Encrypt, and send you the result.
- You paste that into the "Decrypt" box together with your private key to read the original message.
Frequently asked questions
RSA suits short secrets — a password, a one-time code, another system's secret key — not a whole document or file, since it can only encrypt a limited amount of text at once.
RSA can only encrypt up to a few hundred characters at a time, depending on the key length (a longer key holds more). For longer content, encrypt it in separate short pieces, or use RSA only to send a password or secret key and use that for the rest.
No. Generating keys, encrypting and decrypting all happen on your device. Still, the private key is the important part — don't paste it anywhere else, and don't share it with anyone.
Yes, as long as it is standard PEM, starting with "-----BEGIN PUBLIC KEY-----" or "-----BEGIN PRIVATE KEY-----". Some older tools produce private keys as "-----BEGIN RSA PRIVATE KEY-----" (a different format), which needs converting to the standard one first.
Check that the private key is really the matching half of the public key used to encrypt, and that the whole ciphertext was pasted with no extra spaces at the start or end.
It is completely free and needs no sign-up.
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