Extension

public interface Extension

java.security.cert.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.

Summary

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

Public methods

encode

Added in API level 24

 public abstract void encode (OutputStream out)

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

Parameters
`out`	`OutputStream`: the output stream

Throws
`IOException`	on encoding or output error.
`NullPointerException`	if `out` is `null`.

getId

Added in API level 24

 public abstract String getId ()

Gets the extensions's object identifier.

Returns
`String`	the object identifier as a String

getValue

Added in API level 24

 public abstract 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
`byte[]`	a copy of the extension's value, or `null` if no extension value is present.

isCritical

Added in API level 24

 public abstract boolean isCritical ()

Gets the extension's criticality setting.

Returns
`boolean`	true if this is a critical extension.