Is it safe to generate RSA keys in the browser?

Yes. Key generation uses window.crypto.subtle.generateKey(), part of the W3C Web Crypto API built into all modern browsers. The private key is created entirely in your browser's sandboxed JavaScript engine and is never transmitted to any external server.

Which RSA key size should I choose?

2048-bit is the current industry standard, recommended by NIST and supported universally. It offers a strong security/performance balance. 4096-bit provides a larger security margin but is noticeably slower to generate and use. 1024-bit is considered insecure by modern standards and should only be used for legacy testing.

What file format are the keys in?

Public keys are exported in SPKI (SubjectPublicKeyInfo) PEM format, the standard used by TLS/SSL, SSH, and most cryptographic libraries. Private keys are exported in PKCS#8 PEM format, the modern standard accepted by OpenSSL, Node.js crypto, Python cryptography, and Java.

What is the difference between a public key and a private key?

An RSA public key is safe to share publicly. Anyone can use it to encrypt data or verify a digital signature. The private key must be kept secret by the owner. Only the private key can decrypt data encrypted with the corresponding public key, or create signatures that the public key can verify.

How do I use these keys in my application?

Copy the PEM-formatted public key and save it as public.pem. Copy the private key and save it securely as private.pem. In Node.js you can import them with crypto.createPublicKey() and crypto.createPrivateKey(). In Python, use the cryptography library's load_pem_public_key() and load_pem_private_key() functions.

What is RSA-OAEP used for?

RSA-OAEP (Optimal Asymmetric Encryption Padding) is the secure padding scheme used by this generator. It is the recommended padding for RSA encryption, providing semantic security. Keys generated here are suitable for encrypting symmetric keys (e.g. AES keys), secure key exchange, and digital signatures.

ToolsRSA Key Pair Generator

RSA Key Pair Generator

Generate RSA public/private key pairs in PEM format (1024, 2048, 4096-bit). Powered by the Web Crypto API and runs entirely in your browser.

Options

Key Size

Public Key (PEM)Empty

Private Key (PEM)Empty

How to use RSA Key Pair Generator?

1
Select the RSA key size (2048-bit is recommended for most uses).
2
Click Generate Key Pair. Larger keys take longer to compute.
3
Copy the PEM-formatted public and private keys.
4
Keep the private key secret — never share or commit it to source control.

Frequently Asked Questions

Is it safe to generate keys here?

Yes. Keys are generated locally in your browser using the Web Crypto API (crypto.subtle.generateKey). The private key never leaves your device and is not transmitted anywhere.

Which key size should I choose?

2048-bit is the modern standard and offers a strong balance of security and performance. 4096-bit provides extra security margin at the cost of speed. 1024-bit is considered weak and should only be used for legacy testing.

What format are the keys in?

Public keys are exported in SPKI (X.509 SubjectPublicKeyInfo) PEM format and private keys in PKCS#8 PEM format — the standard formats accepted by most libraries and tools.

Generate RSA Key Pairs Online

Quick Answer: RSA is an asymmetric algorithm using a public key to encrypt and a private key to decrypt. This tool generates a fresh key pair in PEM format locally in your browser.

RSA is one of the most widely used public-key cryptosystems, powering TLS/SSL, SSH, JWT signing, and secure messaging. In asymmetric cryptography you hold two mathematically linked keys: anyone can encrypt a message with your public key, but only your private key can decrypt it.

Public Key vs Private Key

Public key: Safe to share. Used to encrypt data or verify signatures.
Private key: Must stay secret. Used to decrypt data or create signatures.
Security tip: Never paste a production private key into any online tool you don't trust. This tool runs client-side, but always treat private keys with care.