X509Extension.getExtensionValue

Gets the DER-encoded OCTET string for the extension value (<em>extnValue</em>) identified by the passed-in {@code oid} string. The {@code oid} string is represented by a set of nonnegative whole numbers separated by periods.

<p>For example:<br> <table border=groove summary="Examples of OIDs and extension names"> <tr> <th>OID <em>(Object Identifier)</em></th> <th>Extension Name</th></tr> <tr><td>2.5.29.14</td> <td>SubjectKeyIdentifier</td></tr> <tr><td>2.5.29.15</td> <td>KeyUsage</td></tr> <tr><td>2.5.29.16</td> <td>PrivateKeyUsage</td></tr> <tr><td>2.5.29.17</td> <td>SubjectAlternativeName</td></tr> <tr><td>2.5.29.18</td> <td>IssuerAlternativeName</td></tr> <tr><td>2.5.29.19</td> <td>BasicConstraints</td></tr> <tr><td>2.5.29.30</td> <td>NameConstraints</td></tr> <tr><td>2.5.29.33</td> <td>PolicyMappings</td></tr> <tr><td>2.5.29.35</td> <td>AuthorityKeyIdentifier</td></tr> <tr><td>2.5.29.36</td> <td>PolicyConstraints</td></tr> </table>

@param oid the Object Identifier value for the extension. @return the DER-encoded octet string of the extension value or null if it is not present.