The Spec mentions: 'The SupportedPrivateKeyFormats specifies the PrivateKey formats supported by the Server. Possible values include “PEM” (see RFC 5958) or “PFX” (see PKCS #12). The array is empty if the Server does not allow external Clients to update the PrivateKey.'

• This we read is for OPC UA Server/Client and this is very fine, but if we want to support a lot of different application which are NOT OPC UA related and we believe that we need to support also other/different DER-formats - like:
  • a. “-----BEGIN PRIVATE KEY-----” PKCS8-format
  • b. “-----BEGIN OPENSSH PRIVATE KEY-----” OpenSSH-format.
  • c. “-----BEGIN RSA PRIVATE KEY-----” TraditionalOpenSSL-format.