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RSA Encrypt/Decrypt Tool — Public-Key Encryption in Your Browser

Encrypt a message using an RSA public key, or decrypt using the matching private key — real public-key cryptography, where a message encrypted with the public key can only be decrypted by whoever holds the private key, computed locally through the Web Crypto API. For generating a new key pair first, use RSA Key Generator.

How to use Rsa Crypto

1. Paste or generate your RSA key.
2. Enter the message to encrypt (with the public key) or ciphertext to decrypt (with the private key).
3. Run the operation.
4. Copy the result.

Frequently asked questions

How is RSA different from AES?

RSA is asymmetric — encryption and decryption use different keys (public and private), which enables secure key exchange between parties who have never met. AES is symmetric — the same key encrypts and decrypts, and is much faster for bulk data, which is why real systems (like HTTPS) typically use RSA to exchange an AES key, then AES for the actual data.

Can I encrypt a large message directly with RSA?

RSA has a message-size limit tied to key size, so in practice it is normally used to encrypt a smaller symmetric key rather than large data directly — which is exactly the hybrid approach real-world protocols use.

Is my private key sent anywhere?

No. Encryption and decryption run entirely in your browser via the Web Crypto API.

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