PEM / Certificate Decoder
Decode PEM-encoded X.509 certificates, RSA keys, and EC keys. View subject, issuer, validity, algorithm, and key details. All client-side.
PEM Input
Supports: CERTIFICATE, PUBLIC KEY, PRIVATE KEY, RSA PUBLIC KEY, EC PRIVATE KEY
Decoded Information
Paste a PEM and click Decode
Certificates, public keys, private keys
100% client-side. Your keys and certificates never leave your browser.
X.509 Certificates
Decode SSL/TLS certificates to see subject, issuer, validity, and algorithm.
Public & Private Keys
Inspect RSA and EC keys to see algorithm, key size, and curve parameters.
Validity Check
Automatically checks if certificates are expired or still valid.
DN Parsing
Extracts Common Name, Organization, Country, and other subject/issuer fields.
Frequently Asked Questions
What is PEM format?
PEM (Privacy Enhanced Mail) is a Base64-encoded format wrapped with -----BEGIN/END----- markers. It's the standard format for certificates, keys, and CSRs in the TLS/SSL ecosystem.
Is my private key safe?
Yes. All decoding happens entirely in your browser using JavaScript. No data is ever transmitted to any server. You can verify this in your browser's network tab.
What can I decode?
X.509 certificates (SSL/TLS), RSA public/private keys, EC public/private keys, and PKCS#8 formatted keys.
Why can't it decode my PEM?
Ensure the PEM includes the full -----BEGIN ... -----/-----END ... ----- markers. Some complex structures (like PKCS#7 chains or encrypted keys) may only show partial information.
Generate your own keys
Try our RSA Key Generator or ECDSA tool to create key pairs.