SSL Certificate Decoder

Paste certificate text and decode its label, decoded byte length and subject lines.

Runs in your browser. Nothing is uploaded — your input is processed on this device and discarded when you close the tab.

SSL Certificate Decoder

How to use this tool

  1. Enter your values in the fields above.
  2. Press Generate to see the result.
  3. Use Load sample to try the worked example, Copy result to copy it, or Clear to start again.

Worked example

A certificate block with body QUJD decodes to 3 bytes, with subject CN=example.com taken from the pasted lines.

What this tool does not do / Limits

This decodes structure from pasted text only: Base64 decode plus field extraction. It is not full ASN.1 validation, does not verify signatures or trust, and performs no live certificate check.

Frequently asked questions

Does this fully validate a certificate?

No. It decodes structure from pasted text only; it is not full ASN.1 validation.

Does this fetch a live certificate?

No. Paste text you already have; the tool never contacts a server itself.

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