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Authorized use only. Use this tool solely on systems, tokens, and assets you own or are explicitly permitted to test — credential extraction, signature forging, and unauthorized access are prohibited by our Acceptable Use Policy.

CSR Decoder (PKCS#10)

Decode a Certificate Signing Request: subject, SANs, public key, extensions, signature. 100% client-side.

Paste CSR (PEM)

About

A Certificate Signing Request (CSR, PKCS#10) is what you send a Certificate Authority to get an SSL/TLS certificate. This decoder parses it entirely in your browser - nothing is uploaded.

Check exactly what a CSR contains before submitting it: subject fields, SANs (which domains it covers), key strength and requested extensions.

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Calculate SHA-1/256/384/512 fingerprints of X.509 certificates from PEM. For SAML, pinning, and TLS debugging.

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Convert RSA keys between PKCS#1 and PKCS#8, public keys between SPKI and PKCS#1, PEM to DER hex. All client-side.