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 | |
abstract String |
getId()
Gets the extensions's object identifier.
|
abstract byte[] |
getValue()
Gets the extensions's DER-encoded value.
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abstract boolean |
isCritical()
Gets the extension's criticality setting.
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Public Methods
public abstract void encode (OutputStream out)
Generates the extension's DER encoding and writes it to the output stream.
Parameters
out | the output stream |
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Throws
IOException | on encoding or output error. |
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NullPointerException | if out is null .
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public abstract String getId ()
Gets the extensions's object identifier.
Returns
- the object identifier as a String
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
- a copy of the extension's value, or
null
if no extension value is present.
public abstract boolean isCritical ()
Gets the extension's criticality setting.
Returns
- true if this is a critical extension.