java.security.cert

Class X509Certificate

java.lang.Object

java.security.cert.Certificate

java.security.cert.X509Certificate

All Implemented Interfaces:

Serializable, X509Extension

public abstract class X509Certificate
extends Certificate
implements X509Extension

Abstract class for X.509 certificates. This provides a standard way to access all the attributes of an X.509 certificate.

In June of 1996, the basic X.509 v3 format was completed by ISO/IEC and ANSI X9, which is described below in ASN.1:

 Certificate  ::=  SEQUENCE  {
     tbsCertificate       TBSCertificate,
     signatureAlgorithm   AlgorithmIdentifier,
     signature            BIT STRING  }
 

These certificates are widely used to support authentication and other functionality in Internet security systems. Common applications include Privacy Enhanced Mail (PEM), Transport Layer Security (SSL), code signing for trusted software distribution, and Secure Electronic Transactions (SET).

These certificates are managed and vouched for by Certificate Authorities (CAs). CAs are services which create certificates by placing data in the X.509 standard format and then digitally signing that data. CAs act as trusted third parties, making introductions between principals who have no direct knowledge of each other. CA certificates are either signed by themselves, or by some other CA such as a "root" CA.

More information can be found in RFC 3280: Internet X.509 Public Key Infrastructure Certificate and CRL Profile.

The ASN.1 definition of tbsCertificate is:

 TBSCertificate  ::=  SEQUENCE  {
     version         [0]  EXPLICIT Version DEFAULT v1,
     serialNumber         CertificateSerialNumber,
     signature            AlgorithmIdentifier,
     issuer               Name,
     validity             Validity,
     subject              Name,
     subjectPublicKeyInfo SubjectPublicKeyInfo,
     issuerUniqueID  [1]  IMPLICIT UniqueIdentifier OPTIONAL,
                          -- If present, version must be v2 or v3
     subjectUniqueID [2]  IMPLICIT UniqueIdentifier OPTIONAL,
                          -- If present, version must be v2 or v3
     extensions      [3]  EXPLICIT Extensions OPTIONAL
                          -- If present, version must be v3
     }
 

Certificates are instantiated using a certificate factory. The following is an example of how to instantiate an X.509 certificate:

 try (InputStream inStream = new FileInputStream("fileName-of-cert")) {
        CertificateFactory cf = CertificateFactory.getInstance("X.509");
        X509Certificate cert = (X509Certificate) cf.generateCertificate(inStream);
 }
 

Author:

Hemma Prafullchandra

See Also:

Certificate, CertificateFactory, X509Extension, Serialized Form

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	X509Certificate() Constructor for X.509 certificates.

Method Summary

Modifier and Type	Method and Description
abstract void	checkValidity() Checks that the certificate is currently valid.
X500Principal	getIssuerX500Principal() Returns the issuer (issuer distinguished name) value from the certificate as an X500Principal.
X500Principal	getSubjectX500Principal() Returns the subject (subject distinguished name) value from the certificate as an X500Principal.

Methods inherited from class java.security.cert.Certificate

equals, getEncoded, getPublicKey, getType, hashCode, toString, verify, verify

Methods inherited from class java.lang.Object

clone, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

X509Certificate

protected X509Certificate()

Constructor for X.509 certificates.

Method Detail

checkValidity

public abstract void checkValidity()
                            throws CertificateExpiredException,
                                   CertificateNotYetValidException

Checks that the certificate is currently valid. It is if the current date and time are within the validity period given in the certificate.

The validity period consists of two date/time values: the first and last dates (and times) on which the certificate is valid. It is defined in ASN.1 as:

 validity             Validity

 Validity ::= SEQUENCE {
     notBefore      CertificateValidityDate,
     notAfter       CertificateValidityDate }

 CertificateValidityDate ::= CHOICE {
     utcTime        UTCTime,
     generalTime    GeneralizedTime }
 

Throws:

CertificateExpiredException - if the certificate has expired.

CertificateNotYetValidException - if the certificate is not yet valid.

getIssuerX500Principal

@Nullable
public X500Principal getIssuerX500Principal()

Returns the issuer (issuer distinguished name) value from the certificate as an X500Principal.

It is recommended that subclasses override this method.

Returns:

an X500Principal representing the issuer distinguished name

Since:

1.4

getSubjectX500Principal

@Nullable
public X500Principal getSubjectX500Principal()

Returns the subject (subject distinguished name) value from the certificate as an X500Principal. If the subject value is empty, then the getName() method of the returned X500Principal object returns an empty string ("").

It is recommended that subclasses override this method.

Returns:

an X500Principal representing the subject distinguished name

Since:

1.4