🔑RSA Key Pair Generator & PKCS#8 / SPKI Exporter Documentation & Guide
Security & Privacy
RSA (Rivest-Shamir-Adleman) remains the foundational asymmetric public-key cryptosystem used globally for TLS handshakes, JWT digital signatures, and SSH authentication. Generating keys in untrusted cloud environments risks private key interception. This utility runs entirely in-browser using standard Web Crypto API primitives to generate cryptographically random RSA key pairs and formats them as standard PKCS#8 private keys and SPKI public keys.
📋How to Generate RSA Key Pairs
- Select Modulus Length: Choose between 2048-bit (standard production speed), 3072-bit (NIST recommended through 2030+), or 4096-bit (long-term root CA and archival security).
- Choose Cryptographic Primitive & Hash: Select your intended cryptographic usage: RSASSA-PKCS1-v1_5 or RSA-PSS for digital signatures, or RSA-OAEP for asymmetric encryption, paired with SHA-256 or SHA-512.
- Generate In-Browser: Click ⚡ Generate New RSA Key Pair. Web Crypto API computes distinct mathematical primes on your device in milliseconds.
- Copy & Download PEM Files: Copy the PKCS#8 private key and SPKI public key to your clipboard or download them as .pem and .pub files.
⚙️RSA Mathematical Architecture & PEM Encoding
RSA security relies on the hardness of factoring large composite semiprime integers n = p * q:
• Key Size Guidelines: 2048-bit provides ~112 bits of symmetric security; 3072-bit provides ~128 bits; 4096-bit provides ~140 bits
• Public Exponent: Standardized to e = 65537 (0x010001, Fermat prime F4) to optimize public key encryption and signature verification speeds
• PKCS#8 Private Key Format: Standardized container defined in RFC 5208 encoding private key type OID and ASN.1 DER structure
• SubjectPublicKeyInfo (SPKI): X.509 standard container (RFC 5280) encoding algorithm identifier and raw public key modulus
• 100% Client-Side Entropy: Primes generated via browser window.crypto.subtle.generateKey with zero network transmission
Always store private keys with strict 600 filesystem permissions and never commit private keys into version control.
💡Practical RSA Key Pair Use Cases
- Generating RS256 private/public key pairs for signing and verifying OAuth 2.0 / OpenID Connect JSON Web Tokens (JWT).
- Creating RSA public-key test fixtures for API gateway authorization and webhook verification.
- Developing mock TLS certificate authorities and client certificate authentication pipelines in local development.
100% Client-Side Privacy Guarantee:All calculations, text manipulation, cryptographic hashing, and media conversions execute exclusively within your local browser sandbox. Zero user inputs, financial amounts, credentials, or proprietary files are ever transmitted across networks or logged on external servers.
