How much content can RSA encrypt?

It is limited by key length: a 2048-bit key with PKCS#1 padding encrypts at most 245 bytes. For long data, use the hybrid scheme — RSA encrypts an AES key, AES encrypts the data.

Can the generated keys be used in production?

Yes — keys are generated locally and never touch the network. For production, though, generating with openssl and storing them carefully is recommended.

RSA Encrypt / Decrypt

Free online RSA tool: generate 1024/2048-bit PEM key pairs locally, encrypt with public key, decrypt with private key.

Privacy: all processing happens locally in your browser. Your input never leaves your device.

What is RSA Encrypt / Decrypt?

RSA is the classic asymmetric cipher: encrypt with the public key, decrypt with the private key — or sign with the private key and verify with the public key. It is widely used for API encryption and license issuance. This tool generates 1024/2048-bit key pairs (PEM format) locally in your browser and encrypts or decrypts short texts, ideal for testing RSA flows. Keys live only in browser memory and vanish on refresh.

How to Use

Generate a key pair (or paste an existing PEM key)
Encrypt plaintext with the public key / decrypt ciphertext with the private key
Copy the result

FAQ

How much content can RSA encrypt?: It is limited by key length: a 2048-bit key with PKCS#1 padding encrypts at most 245 bytes. For long data, use the hybrid scheme — RSA encrypts an AES key, AES encrypts the data.
Can the generated keys be used in production?: Yes — keys are generated locally and never touch the network. For production, though, generating with openssl and storing them carefully is recommended.

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Last updated 2026-09-04