RSA Encrypt & Decrypt Tool
Encrypt messages with an RSA Public Key and decrypt them with the matching RSA Private Key using RSA-OAEP.
1 How to Use the RSA Encrypt & Decrypt Tool
To Encrypt: Paste recipient's Public Key PEM, type message, click 'Encrypt with Public Key'.
Copy the resulting Base64 ciphertext.
To Decrypt: Paste your Private Key PEM and ciphertext, click 'Decrypt with Private Key'.
View decrypted plain text instantly.
2 Technical Specifications
| Specification | Details & Capabilities |
|---|---|
| Padding Scheme | RSA-OAEP with SHA-256 hash |
| Supported Keys | PEM formatted PKCS#8 and SPKI keys |
| Output Format | Standard Base64 string |
| Engine | Web Crypto API (crypto.subtle.encrypt / decrypt) |
Trust and Privacy
100% Client-Side Privacy Guarantee
All calculations run directly in your local browser memory. Zero data is ever transmitted, logged, or stored on remote servers.
4 Frequently Asked Questions
Q. Can everyone read my message encrypted with a public key?
No. Anyone can encrypt using your public key, but only the person holding the secret private key can decrypt and read it.
Q. Why is RSA limited in message length?
RSA cannot encrypt data larger than its key modulus (around 190 bytes for 2048-bit keys). In practice, RSA encrypts a symmetric AES key, which encrypts large payloads.