Certificate (PEM) Decoder
Decode PEM certificates and view details.
How to Use
Paste a PEM-encoded certificate into the input field and the tool will parse and display all certificate details, including the subject, issuer, validity period, serial number, signature algorithm, public key information, and X.509 extensions like Subject Alternative Names (SANs).
Common Use Cases
- Inspecting SSL/TLS certificates to verify domain names and expiration dates
- Debugging certificate chain issues by examining issuer and subject fields
- Checking Subject Alternative Names (SANs) on multi-domain certificates
- Reviewing certificate details before deploying to a web server or load balancer
Frequently Asked Questions
What types of PEM files can this tool decode?
The tool can decode X.509 certificates (BEGIN CERTIFICATE), certificate signing requests (BEGIN CERTIFICATE REQUEST), and public keys (BEGIN PUBLIC KEY). Private keys are parsed for structure but sensitive material is handled carefully.
Can I check if a certificate is expired?
Yes. The tool displays the "Not Before" and "Not After" dates and clearly indicates whether the certificate is currently valid, not yet valid, or expired.
Does this tool validate the certificate chain?
The tool decodes and displays individual certificate details but does not perform full chain validation (which requires the complete chain of trust up to a trusted root CA).