public interface X509Extension
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.Modifier and Type | Method and Description |
---|---|
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.
|
byte[] |
getExtensionValue(String oid)
Gets the DER-encoded OCTET string for the extension value
(extnValue) identified by the passed-in
oid
String. |
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.
|
boolean |
hasUnsupportedCriticalExtension()
Check if there is a critical extension that is not supported.
|
boolean hasUnsupportedCriticalExtension()
Set<String> getCriticalExtensionOIDs()
InputStream inStrm = null;
X509Certificate cert = null;
try {
inStrm = new FileInputStream("DER-encoded-Cert");
CertificateFactory cf = CertificateFactory.getInstance("X.509");
cert = (X509Certificate)cf.generateCertificate(inStrm);
} finally {
if (inStrm != null) {
inStrm.close();
}
}
Set critSet = cert.getCriticalExtensionOIDs();
if (critSet != null && !critSet.isEmpty()) {
System.out.println("Set of critical extensions:");
for (String oid : critSet) {
System.out.println(oid);
}
}
Set<String> getNonCriticalExtensionOIDs()
InputStream inStrm = null;
CertificateFactory cf = null;
X509CRL crl = null;
try {
inStrm = new FileInputStream("DER-encoded-CRL");
cf = CertificateFactory.getInstance("X.509");
crl = (X509CRL)cf.generateCRL(inStrm);
} finally {
if (inStrm != null) {
inStrm.close();
}
}
byte[] certData = <DER-encoded certificate data>
ByteArrayInputStream bais = new ByteArrayInputStream(certData);
X509Certificate cert = (X509Certificate)cf.generateCertificate(bais);
bais.close();
X509CRLEntry badCert =
crl.getRevokedCertificate(cert.getSerialNumber());
if (badCert != null) {
Set nonCritSet = badCert.getNonCriticalExtensionOIDs();
if (nonCritSet != null)
for (String oid : nonCritSet) {
System.out.println(oid);
}
}
byte[] getExtensionValue(String oid)
oid
String.
The oid
string is
represented by a set of nonnegative whole numbers separated
by periods.
For example:
OID (Object Identifier) | Extension Name |
---|---|
2.5.29.14 | SubjectKeyIdentifier |
2.5.29.15 | KeyUsage |
2.5.29.16 | PrivateKeyUsage |
2.5.29.17 | SubjectAlternativeName |
2.5.29.18 | IssuerAlternativeName |
2.5.29.19 | BasicConstraints |
2.5.29.30 | NameConstraints |
2.5.29.33 | PolicyMappings |
2.5.29.35 | AuthorityKeyIdentifier |
2.5.29.36 | PolicyConstraints |
oid
- the Object Identifier value for the extension. Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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