PEM Viewer

What Is a PEM File?

PEM (Privacy-Enhanced Mail) is a base64-encoded format for cryptographic keys and certificates. PEM files are identified by header and footer lines such as -----BEGIN CERTIFICATE----- and -----END CERTIFICATE-----. They can contain X.509 certificates, RSA and EC private keys, certificate signing requests (CSRs), and other cryptographic objects. This tool decodes PEM-encoded data and presents the parsed fields in a human-readable format. For certificates, it shows subject, issuer, validity dates, serial number, signature algorithm, public key algorithm, and key size. For private keys, it displays the key type (RSA or EC), key size, and curve name. For CSRs, it shows the subject, public key, and attributes.

How to Use This Tool

1. Paste your PEM data — Enter or paste a PEM-encoded certificate, key, or CSR into the input area.
2. Click Decode — The tool parses the base64 content between the header and footer lines and extracts the ASN.1 structure.
3. Review the details — Fields are displayed in a structured card layout grouped by category (subject, issuer, validity, public key, extensions).
4. Use examples — Click the example buttons (Certificate, RSA Key, EC Key, CSR) to see sample PEM data and decoded results.
5. Clear and repeat — Click Clear to reset and decode another PEM object.

Frequently Asked Questions