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X.509 Certificate Parser

Encoding & Encryption · Free Online Tool

Parse SSL/TLS certificates in PEM/DER and inspect fields.

By CoderNewbie Team
0 PEM block(s) · 0 certificate(s)
0 chars
No PEM blocks found. Paste a certificate between -----BEGIN CERTIFICATE----- and -----END CERTIFICATE----- markers.

ASN.1 DER Parser

Walks the DER structure in pure JavaScript to extract TBS fields — no native dependency.

Subject & Issuer

Decodes the Name RDN sequences and maps common OIDs (CN, O, OU, C, emailAddress).

Validity & Serial

Shows notBefore/notAfter dates, the serial number (hex), and the signature algorithm.

How to Use X.509 Certificate Parser

  1. 1Enter or paste your data into the input field.
  2. 2Select the desired encoding, hashing, or encryption options.
  3. 3Click the action button to process your data.
  4. 4Copy the result from the output field.

Features

  • ✓100% free — no signup, no subscription, no ads
  • ✓Runs entirely in your browser — data never leaves your device
  • ✓Fast and lightweight — instant results
  • ✓Cross-platform — works on desktop, tablet, and mobile

Frequently Asked Questions

Is my data safe?

Yes. All encoding, hashing, and encryption operations run entirely in your browser. Your data is never sent to any server.

Can I use this for passwords?

We recommend using the Password Generator for creating secure passwords, and Bcrypt Hash for storing password hashes. Never store plain-text passwords.

What hash algorithms are supported?

The Hash Generator supports MD5, SHA-1, SHA-256, and SHA-512. For HMAC signatures, use the HMAC Generator.

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Learn the concept

Learn the concept

Understand the programming ideas behind this tool.

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