X509Extension

public interface X509Extension
Known Indirect Subclasses

Interface for an X.509 extension.

The extensions defined for X.509 v3 Certificates and v2 CRLs (Certificate Revocation Lists) provide methods for associating additional attributes with users or public keys, for managing the certification hierarchy, and for managing CRL distribution. The X.509 extensions format also allows communities to define private extensions to carry information unique to those communities.

Each extension in a certificate/CRL may be designated as critical or non-critical. A certificate/CRL-using system (an application validating a certificate/CRL) must reject the certificate/CRL if it encounters a critical extension it does not recognize. A non-critical extension may be ignored if it is not recognized.

The ASN.1 definition for this is:

 Extensions  ::=  SEQUENCE SIZE (1..MAX) OF Extension

 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
 }
 
Since not all extensions are known, the getExtensionValue method returns the DER-encoded OCTET STRING of the extension value (i.e., the extnValue). This can then be handled by a Class that understands the extension.

Public Method Summary

abstract Set<String>
getCriticalExtensionOIDs()
Gets a Set of the OID strings for the extension(s) marked CRITICAL in the certificate/CRL managed by the object implementing this interface.
abstract byte[]
getExtensionValue(String oid)
Gets the DER-encoded OCTET string for the extension value (extnValue) identified by the passed-in oid String.
abstract Set<String>
getNonCriticalExtensionOIDs()
Gets a Set of the OID strings for the extension(s) marked NON-CRITICAL in the certificate/CRL managed by the object implementing this interface.
abstract boolean
hasUnsupportedCriticalExtension()
Check if there is a critical extension that is not supported.