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.

Public Method Summary

abstract void
encode(OutputStream out)
Generates the extension's DER encoding and writes it to the output stream.
abstract String
Gets the extensions's object identifier.
abstract byte[]
Gets the extensions's DER-encoded value.
abstract boolean
Gets the extension's criticality setting.

Public Methods

public abstract void encode (OutputStream out)

Generates the extension's DER encoding and writes it to the output stream.

out the output stream
IOException on encoding or output error.
NullPointerException if out is null.

public abstract String getId ()

Gets the extensions's object identifier.

  • the object identifier as a String

public abstract byte[] getValue ()

Gets the extensions's DER-encoded va