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Certificate Converter

Certificate Converter transforms certificate/request data between PEM and raw Base64 (DER body), helping when one platform exports with BEGIN/END markers while another expects only plain Base64 payload.

Use PEM → Base64 when importing into systems that require DER body only (for API payloads or secret stores), and Base64 → PEM when you need human-readable blocks that can be inspected or reused with OpenSSL tooling.

The converter validates input before output, so malformed Base64/PEM data is rejected immediately to reduce copy/paste mistakes during certificate operations.

Example commands

Windows (cmd)

                      findstr /v /c:"-----" certificate.pem > certificate.base64

Windows (PowerShell)

                      (Get-Content .\certificate.pem | Select-String -NotMatch '-----').Line | Set-Content .\certificate.base64

Linux (OpenSSL)

                      openssl x509 -in certificate.pem -outform DER | base64 -w 0 > certificate.base64

Format differences and recognition

  • PEM: Base64 data wrapped in headers like -----BEGIN CERTIFICATE-----.
  • DER: Binary ASN.1 format (not directly readable text).
  • Base64 DER body: Text-only DER payload without PEM headers/footers.
  • Recognition tip: BEGIN/END markers indicate PEM; unreadable binary indicates DER; plain Base64 text indicates DER body.