CSR Decoder
Processing: API. Processed by cent-ai's API: sent to our server, held in memory, never stored.Paste a PEM-encoded PKCS#10 certificate signing request to see its subject, public key details, signature algorithm, and requested subject alternative names. Nothing you paste here is stored or logged.
How to use it
- Paste a PEM-encoded CSR, starting with
-----BEGIN CERTIFICATE REQUEST-----. - Details appear automatically, or select “Decode CSR” to run it immediately.
- Copy the result to your clipboard.
Example
Select “Use example” above to load a sample CSR.
Privacy and security
- The CSR is sent to our API only to decode it; it is never persisted or logged.
- Parsing happens in memory using a structural ASN.1 decoder — no code execution over the input, no network access.
- Requests are not included in analytics or error reporting.
Limitations
- The CSR’s signature is not cryptographically verified — structure and fields only.
- A private key or certificate pasted by mistake is rejected, not decoded.
FAQ
Does this tool verify the CSR's signature?
No — it decodes the structure and fields only. A CSR is self-signed by the applicant's own key as proof of possession, so there's no CA trust to check the way there is for a certificate.
What extensions does it show?
Subject alternative names are decoded and listed explicitly. Any other requested extensions are listed by their OID rather than silently dropped.
What's the difference between this and the Certificate Decoder?
A CSR is what you submit to a CA to request a certificate; a certificate is what the CA issues back, signed by them. Use this tool for the request, the Certificate Decoder for the issued result.