Free RSA Key Pair Generator

The RSA Key Pair Generator is a free online tool that generate rsa public/private key pairs (1024, 2048, or 4096-bit) in your browser using the web crypto api. nothing is transmitted to any server.. It runs entirely in your browser with no installation or sign-up needed.

2048-bit (recommended), 4096-bit (maximum security), and 1024-bit (legacy).

Yes, completely free.

Absolutely. The RSA Key Pair Generator processes everything client-side in your browser. No data is uploaded to or stored on any server. Your content remains private on your device at all times.

Yes, the RSA Key Pair Generator is fully responsive and works on smartphones and tablets. You can use it on any device with a modern web browser -- no app download required.

No account or registration is needed. Simply open the RSA Key Pair Generator in your browser and start using it immediately. There are no sign-up walls or usage restrictions.

Simply enter your input in the provided field, adjust any settings to your preference, and the tool will process it instantly. You can then copy the result to your clipboard or download it.

The RSA Key Pair Generator works in all modern browsers including Chrome, Firefox, Safari, Edge, and Opera. For the best experience, use the latest version of your preferred browser.

RSA is an asymmetric system, so the tool produces two mathematically linked keys with opposite roles. The private key is secret and is used to sign data; the public key is shareable and is used by others to verify those signatures. You can publish or embed the public key freely — hand it to any service that needs to confirm your signatures — but the private key must stay confidential, because anyone who obtains it can sign data as you. The pair only works together: a signature made with one private key verifies solely against its matching public key. Here the public key is exported in SPKI PEM (the BEGIN PUBLIC KEY block) and the private key in PKCS#8 PEM. Generate a pair above, then copy or download each .pem file separately, guarding the private one.

2048-bit is the recommended default and the current baseline for most systems; it is widely regarded as secure for general use into the foreseeable future and generates almost instantly. 4096-bit doubles the modulus length for a larger security margin, which suits long-lived keys or stricter compliance needs, but it is slower to generate and slower at every sign operation afterward. For most testing, learning, and everyday signing tasks, 2048-bit is the practical sweet spot. The 1024-bit option exists only for legacy compatibility and is considered insecure by modern standards, so the tool flags it with a warning. Generation speed also depends on your own hardware, since everything runs locally. Pick your size from the dropdown above, click Generate Key Pair, and compare how quickly each completes on your device.

The keys this tool creates are configured for digital signatures, not direct message encryption. They use the RSASSA-PKCS1-v1_5 scheme with the standard public exponent of 65537, and are exported with the sign and verify key usages. That means you sign data with the private key and anyone with the public key can verify it, which proves authenticity and integrity. If you need to encrypt a message so only the holder of the private key can read it, you would want keys generated with an encryption scheme such as RSA-OAEP instead — these signing keys are not intended for that workflow. For testing signature flows, authentication, or learning how asymmetric signing works, generate a pair above and feed the PEM output straight into your code or OpenSSL.

You get two PEM-encoded blocks that are widely understood across tooling. The public key is exported in SPKI format, wrapped in the -----BEGIN PUBLIC KEY----- envelope, and the private key in PKCS#8 format, wrapped in -----BEGIN PRIVATE KEY-----. Both are standard, base64-encoded DER structures that OpenSSL, language crypto libraries, and most key-handling tools parse natively — for example you can inspect the public key with openssl pkey or openssl rsa. These are the modern, generic PEM envelopes rather than the older RSA-specific headers, so if a system expects a traditional PKCS#1 BEGIN RSA PRIVATE KEY block you may need a quick OpenSSL conversion. Generate your pair above, then copy or download public-key.pem and private-key.pem to drop straight into your toolchain.

After generation, the tool displays a SHA-256 fingerprint of the public key — a short, fixed-length digest computed by hashing the key's bytes. Because any change to the key produces a completely different hash, the fingerprint acts as a compact identifier you can compare without sharing or eyeballing the entire PEM block. Its main use is verification: two parties can read out or paste their fingerprints and confirm they are looking at the exact same public key, guarding against a swapped or tampered key. It is far quicker to compare a short fingerprint than to diff multi-line key files by hand. The fingerprint is derived locally in your browser alongside the keys. Generate a pair above, then match the displayed SHA-256 fingerprint against the one your counterpart expects.