UsefulVerse
Language · English

Free to use, no account

RSA Key Generator

Create an RSA-OAEP key pair in this browser, inspect its public-key fingerprint, and test a short message. Nothing is uploaded or saved by this tool.

Uses RSA-OAEP with SHA-256. Key generation may take a moment, especially at 4096 bits; a computer is recommended for that size.

Test a short message

RSA-OAEP is for short messages only. With SHA-256, the limit is 190 UTF-8 bytes for this key size; use hybrid encryption for larger data.

This is a local format and encryption demo, not a certificate, identity check, digital signature, or audited security product.

How do I generate an RSA key pair?

Choose 2048, 3072 or 4096 bits and select Generate. The browser creates a public SPKI PEM and a private PKCS8 PEM. Copy or download either key only when you need it.

Frequently asked questions

How do I generate an RSA key pair?

Choose 2048, 3072 or 4096 bits and select Generate. The browser creates a public SPKI PEM and a private PKCS8 PEM. Copy or download either key only when you need it.

Are my keys uploaded or stored?

No. Web Crypto generates and uses the keys in this tab. The private key is displayed because you asked to create it; this page does not upload or persist it. Do not use a public browser tool for production secrets.

How much text can RSA encrypt?

Only a short message. RSA-OAEP with SHA-256 allows at most 190, 318 or 446 UTF-8 bytes for 2048-, 3072- or 4096-bit keys. RSA is not a file-encryption method; use a reviewed hybrid-encryption design for larger data.

What do SPKI and PKCS8 mean?

SPKI is the standard SubjectPublicKeyInfo format used here for a public key. PKCS8 is the private-key container. Keep the PKCS8 private key confidential and make a secure backup yourself if you need one.

Does this create a trusted certificate or a digital signature?

No. It creates an RSA-OAEP encryption key pair for a small demonstration. It does not issue certificates, prove identity, create signatures, or make a key trusted.

Is this suitable for production encryption?

This page is a learning and interoperability demo, not an audited cryptographic application. Do not paste real secrets into a public computer, and do not rely on this page to manage or safeguard production keys.