CSR Decoder

The CSR Decoder analyzes certificate signing requests to extract core certificate request data and present it in a structured form for engineers. It supports PEM and DER encodings and identifies the subject DN, public key algorithm and size, signature algorithm, and standard extensions such as SAN, keyUsage, extendedKeyUsage, and basicConstraints. Users can inspect algorithm names, key lengths, and extension content to verify CSR intent before forwarding to a CA. Conceptually, the tool performs ASN.1/DER parsing, maps OIDs to readable names, and conditionally validates the CSR signature when requested. This helps teams confirm that the CSR aligns with security and policy requirements, such as SAN coverage and key strength, without issuing any certificate itself. Unique value comes from precise, auditable extraction and the ability to flag policy gaps prior to submission. Common use cases include pre-issuance validation in CI pipelines, security audits of customer or partner CSRs, and rapid triage of submissions in PKI operations.