RSA Key Inspector
Inspect RSA/EC public keys and certificates: algorithm, key size, exponent, curve, validity dates, and security-strength verdict. DER-parsed in your browser.
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What is RSA Key Inspector?
RSA Key Inspector decodes PEM public keys and X.509 certificates in your browser with a built-in DER parser: it identifies RSA or EC algorithms, extracts key size, exponent, and curve, reads certificate validity dates, computes a SHA-256 fingerprint via WebCrypto, and grades the security strength.
Key Benefits
- Spot weak 1024-bit RSA keys in seconds
- Read certificate validity dates without OpenSSL
- Named EC curves instead of raw OID numbers
- SHA-256 fingerprint computed locally via WebCrypto
- Completely private - keys never leave your device
Common Use Cases
- •Auditing TLS certificates and SSH host keys for weak sizes
- •Verifying key rotations landed with the intended parameters
- •Checking certificate expiry dates during incident triage
- •Teaching developers how public key formats are structured
How to Inspect a Public Key
- Paste the PEM: Paste a PUBLIC KEY or CERTIFICATE PEM block - parsing starts as you paste.
- Read the details: Check the algorithm, key size, exponent or curve, and validity dates extracted from the DER.
- Act on the verdict: Use the strength verdict: migrate weak 1024-bit RSA keys and expired certificates immediately.
Key Features
- Built-in DER parser handles SPKI public keys and X.509 certificates
- RSA modulus size and public exponent extraction
- EC curve identification: P-256, P-384, P-521
- Certificate validity dates from UTCTime and GeneralizedTime
- SHA-256 fingerprint computed locally via WebCrypto
- Security-strength verdict: strong, good, weak, or broken