RSA Encryption: Generate Keys & Encrypt Online | Free Tool
4 usesPublic Key
Private Key
RSA Encryption Tips
RSA-2048 Key Generation
Generate secure RSA-2048 key pairs (public + private) using the browser Web Crypto API.
Asymmetric Encryption
Encrypt with the public key, decrypt with the private key. Perfect for secure message exchange.
Browser-Based Crypto
Uses the Web Crypto API — all key generation and encryption happens locally in your browser.
Size Limitation
RSA-2048 can encrypt up to ~190 bytes of data. For larger data, use AES with an RSA-encrypted key.
Frequently Asked Questions
How does RSA encryption work?
RSA uses a pair of keys: a public key for encryption and a private key for decryption. Anyone can encrypt with the public key, but only the private key holder can decrypt.
What is the maximum data size?
RSA-2048 with OAEP can encrypt up to about 190 bytes. For larger data, encrypt with AES and use RSA to encrypt the AES key.
Are the keys stored anywhere?
No. Keys are generated in your browser and exist only in memory. They are lost when you close the page.
Is this free?
Yes.
How can I securely share a short secret message using this RSA tool?
To share a secret message, generate an RSA key pair first. Provide the recipient with your *public key*. They will use this key to encrypt their message using the tool. Once encrypted, they send you the ciphertext. You can then use your *private key* (which you never shared) within the tool to decrypt the message privately and securely in your browser. Remember RSA is best for small messages.
How can I generate RSA key pairs for API authentication with this browser-based tool?
Yes, this RSA Encryption & Key Generator can be used to create RSA-2048 key pairs suitable for API authentication. Generate your key pair in the browser and copy the public key to configure with your API service provider. Keep your private key extremely secure, as it's essential for signing requests or decrypting sensitive API responses. Since keys are generated locally in your browser, it adds a layer of privacy for your authentication credentials.
How to Use RSA Encryption
- Click Generate Key Pair to create public and private keys
- Enter text to encrypt (max ~190 bytes)
- Click Encrypt to encrypt with the public key
- Paste ciphertext and click Decrypt to decrypt with the private key