Module java.base
Package java.security.cert

Interface Extension

  • public interface Extension
    This interface represents an X.509 extension.

    Extensions provide a means of associating additional attributes with users or public keys and for managing a certification hierarchy. The extension format also allows communities to define private extensions to carry information unique to those communities.

    Each extension contains an object identifier, a criticality setting indicating whether it is a critical or a non-critical extension, and and an ASN.1 DER-encoded value. Its ASN.1 definition is: 

    
     Extension ::= SEQUENCE {
         extnId        OBJECT IDENTIFIER,
         critical      BOOLEAN DEFAULT FALSE,
         extnValue     OCTET STRING
                 -- contains a DER encoding of a value
                 -- of the type registered for use with
                 -- the extnId object identifier value
     }

    This interface is designed to provide access to a single extension, unlike X509Extension which is more suitable for accessing a set of extensions.

    Since:
    1.7

    • Method Summary

      Modifier and Type Method Description
      void encode​(OutputStream out)
      Generates the extension's DER encoding and writes it to the output stream.
      String getId()
      Gets the extensions's object identifier.
      byte[] getValue()
      Gets the extensions's DER-encoded value.
      boolean isCritical()
      Gets the extension's criticality setting.

    • Method Detail

      • getId

        String getId()
        Gets the extensions's object identifier.
        Returns:
        the object identifier as a String

      • isCritical

        boolean isCritical()
        Gets the extension's criticality setting.
        Returns:
        true if this is a critical extension.

      • getValue

        byte[] getValue()
        Gets the extensions's DER-encoded value. Note, this is the bytes that are encoded as an OCTET STRING. It does not include the OCTET STRING tag and length.
        Returns:
        a copy of the extension's value, or null if no extension value is present.