Rsa Key Pair Generator

Free online tool. All processing is client-side. No signup needed.

How to Use the Rsa Key Pair Generator

1. Enter your input values above
2. Results update automatically
3. Copy or download the output

What is a Rsa Key Pair Generator?

An RSA Key Pair Generator creates public/private key pairs for asymmetric encryption, digital signatures, and SSH authentication. RSA (Rivest-Shamir-Adleman, 1977) is the most widely deployed public-key cryptosystem — used in TLS/SSL certificates, SSH connections, PGP email encryption, and digital signatures. The security of RSA rests on the mathematical difficulty of factoring the product of two large prime numbers.

How Does It Work?

Select key size (2048 or 4096 bits). The generator: (1) generates two large random prime numbers (p, q), (2) computes n = p × q (the modulus), (3) computes φ(n) = (p−1)(q−1), (4) selects public exponent e (typically 65537), (5) computes private exponent d = e⁻¹ mod φ(n). Public key = (n, e); Private key = (n, d). Output in PEM format (PKCS#1 or PKCS#8), suitable for immediate use.

Formula

Key Generation:\np, q = large random primes (each ~key_size/2 bits)\nn = p × q (modulus, key_size bits)\nφ(n) = (p−1)(q−1)\ne = 65537 (standard public exponent)\nd = e⁻¹ mod φ(n) (modular multiplicative inverse)\n\nEncryption: c = m^e mod n\nDecryption: m = c^d mod n\n\nKey Sizes:\n2048-bit: secure through ~2030\n4096-bit: secure beyond 2030, but slower\n\n⚠️ Key generation is computationally intensive. Browser-based generation is for testing/demo only.

Who Uses This Tool?

• Developers generating test RSA keys for development and CI/CD
• SSH key generation for server access (use ssh-keygen for production)
• Education: understanding public-key cryptography
• Testing TLS certificate chains and PKI infrastructure

Pro Tips

• For production SSH keys: use `ssh-keygen -t rsa -b 4096` or `ssh-keygen -t ed25519` (Ed25519 is preferred — faster and more secure)
• 2048-bit RSA is estimated secure until ~2030. NIST recommends 2048-bit minimum. Use 3072 or 4096-bit for long-lived keys
• This tool is for testing/education. Production keys should be generated in a secure environment (HSM, secure enclave, or trusted local machine)

Frequently Asked Questions about Rsa Key Pair Generator

RSA vs Ed25519 — which is better?

Ed25519: faster, smaller keys, same security as 3072-bit RSA, more resistant to implementation errors. RSA: broader compatibility, better hardware acceleration. For new systems: Ed25519 (or ECDSA P-256). SSH: Ed25519 is now standard.

How long does RSA key generation take?

4096-bit generation takes seconds to minutes depending on CPU and luck (finding large primes). 2048-bit is typically under 10 seconds. Browser-based generation is slower than native tools.

Free online Rsa Key Pair Generator — no signup, 100% client-side processing. All data stays in your browser.