1024 – 4096-Bit Key Generation
Generate RSA key pairs in any standard size. NIST-recommended 2048-bit for current use; 4096-bit for maximum long-term security. All computed via the native Web Crypto API.
What is RSA Encryption & Why Use an RSA Key Generator?
RSA — named after its inventors Rivest, Shamir and Adleman — is the most widely deployed asymmetric cryptographic algorithm in the world. Published in 1977, it underpins the security of HTTPS/TLS, SSH authentication, email encryption (PGP/S-MIME), digital certificates and countless enterprise security systems. Unlike symmetric ciphers which share a single secret key, RSA uses a mathematically linked key pair: a freely shareable public key and a closely guarded private key.
The public key can safely be distributed to anyone. Senders use it to encrypt data that only the private key holder can decrypt, or to verify digital signatures produced by the private key. The private key must remain secret at all times — it is what decrypts incoming messages and what produces unforgeable digital signatures that prove the sender's identity.
Choosing the right key size is critical. 1024-bit RSA is obsolete and should never be used in new systems. NIST recommends 2048-bit RSA as the minimum for use until at least 2030, while 4096-bit keys provide significantly stronger security suitable for long-lived certificates, root CAs and high-sensitivity applications. Larger keys are computationally slower but provide a far larger security margin against future attacks, including advances in classical and quantum computing.
In SSH (Secure Shell) authentication, RSA is used in the ssh-rsa format. You generate a key pair, place the public key in the server's ~/.ssh/authorized_keys file, and keep the private key locally on your client. This eliminates password-based authentication, removing a major attack vector. Modern SSH clients and servers also support ECDSA and Ed25519, but RSA 4096 remains universally supported and widely trusted.
Best practices when using RSA keys: always generate keys locally in a secure environment; never reuse key pairs across different services; store private keys in encrypted keystores or hardware security modules (HSMs); use passphrase protection on private key files; rotate keys periodically; and revoke any key that may have been compromised immediately. This free RSA Key Generator follows all cryptographic standards, runs entirely in your browser via the Web Crypto API, and never transmits your sensitive key material anywhere.