Cryptography & Security

RSA Key Pair Generator

Create an RSA key pair directly in the browser using the Web Crypto API — handy for local testing, SSH experiments, or JWT signing setups.

Free & unlimitedRuns in your browserNo sign-up required

Key Size (bits)

RSA Key Pair Generator

RSA is one of the oldest and still most widely used public-key cryptography systems, powering everything from SSH authentication to TLS certificates to PGP-encrypted email. The core idea is elegant: instead of one shared secret that both sides need to protect, you generate two mathematically linked keys. One is public and can be shared with anyone. One is private and never leaves your machine.

Public-key cryptography

Anything encrypted with the public key can only be decrypted with the matching private key. Anything signed with the private key can be verified by anyone holding the public key. That asymmetry solves a problem symmetric encryption can't: how do two parties who've never met agree on a secret over an insecure channel?

Key sizes and security

This tool generates a fresh RSA key pair in PEM format at 1024, 2048, or 4096 bits. 1024-bit RSA is considered breakable by well-resourced attackers today and shouldn't be used for anything beyond legacy compatibility testing. 2048-bit is the current baseline for real-world security, used by most SSH keys and TLS certificates issued today. 4096-bit doubles the key size for extra long-term margin, at the cost of slower key generation and operations.

PEM Format

PEM format is the standard text-based encoding, the "-----BEGIN RSA PRIVATE KEY-----" block you've probably seen if you've ever set up SSH access to a server. It's base64-encoded binary data wrapped in a readable header and footer, which makes it easy to copy, paste, and store in config files or environment variables.

Important Note

Never use a key pair generated by any online tool, including this one, for a real production system holding meaningful value or sensitive data. Generate production keys on the actual machine that will use them, using tools like openssl or ssh-keygen locally, so the private key is never transmitted anywhere at all. This tool is built for learning, testing, and prototyping.

Loading tool…

How it works

Three steps, no setup

Pick a key size

2048-bit is the current baseline; use 4096-bit when you need extra headroom.

Generate the pair

The keys are produced locally using your browser's native crypto engine.

Download the PEM files

Save the private and public keys separately and keep the private key out of version control.

Common questions

Frequently asked questions

Are these keys safe to use in production?

The generation itself is cryptographically sound, but treat any key created in a browser tab as disposable — for production secrets, generate keys on a controlled server or hardware device.

Why is 1024-bit available if it is weak?

It is included only for compatibility testing against legacy systems. For anything real, use 2048-bit or higher.

RSA Key Pair Generator

RSA Key Pair Generator

Public-key cryptography

Key sizes and security

PEM Format

Important Note

Three steps, no setup

Pick a key size

Generate the pair

Download the PEM files

Frequently asked questions

Related tools

Hash Generator

Bcrypt Generator

HMAC Generator

Text Encrypt / Decrypt

BIP39 Mnemonic Generator

Password Strength Analyser

twoworks

RSA Key Pair Generator

Public-key cryptography

Key sizes and security

PEM Format

Important Note