https://openjdk.java.net/ 
/*
 * Copyright (c) 1997, 2006, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */


package javax.security.cert;

import java.io.InputStream;
import java.lang.Class;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.security.Security;

import java.math.BigInteger;
import java.security.AccessController;
import java.security.Principal;
import java.security.PrivilegedAction;
import java.security.PublicKey;
import java.util.BitSet;
import java.util.Date;


Abstract class for X.509 v1 certificates. This provides a standard
way to access all the version 1 attributes of an X.509 certificate.
Attributes that are specific to X.509 v2 or v3 are not available
through this interface. Future API evolution will provide full access to
complete X.509 v3 attributes.


The basic X.509 format was defined by
ISO/IEC and ANSI X9 and 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.


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,
    }




Here is sample code to instantiate an X.509 certificate:

InputStream inStream = new FileInputStream("fileName-of-cert");
X509Certificate cert = X509Certificate.getInstance(inStream);
inStream.close();


OR

byte[] certData = <certificate read from a file, say>
X509Certificate cert = X509Certificate.getInstance(certData);




In either case, the code that instantiates an X.509 certificate
consults the Java security properties file to locate the actual
implementation or instantiates a default implementation.


The Java security properties file is located in the file named
<JAVA_HOME>/lib/security/java.security.
<JAVA_HOME> refers to the value of the java.home system property,
and specifies the directory where the JRE is installed.
In the Security properties file, a default implementation
for X.509 v1 may be given such as:

cert.provider.x509v1=com.sun.security.cert.internal.x509.X509V1CertImpl




The value of this cert.provider.x509v1 property has to be
changed to instatiate another implementation. If this security
property is not set, a default implementation will be used.
Currently, due to possible security restrictions on access to
Security properties, this value is looked up and cached at class
initialization time and will fallback on a default implementation if
the Security property is not accessible.

Note: The classes in the package javax.security.cert
exist for compatibility with earlier versions of the
Java Secure Sockets Extension (JSSE). New applications should instead
use the standard Java SE certificate classes located in
java.security.cert.


Author:Hemma Prafullchandra
See Also:
Since:1.4
/**
 * Abstract class for X.509 v1 certificates. This provides a standard
 * way to access all the version 1 attributes of an X.509 certificate.
 * Attributes that are specific to X.509 v2 or v3 are not available
 * through this interface. Future API evolution will provide full access to
 * complete X.509 v3 attributes.
 * <p>
 * The basic X.509 format was defined by
 * ISO/IEC and ANSI X9 and is described below in ASN.1:
 * <pre>
 * Certificate  ::=  SEQUENCE  {
 *     tbsCertificate       TBSCertificate,
 *     signatureAlgorithm   AlgorithmIdentifier,
 *     signature            BIT STRING  }
 * </pre>
 * <p>
 * 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).
 * <p>
 * These certificates are managed and vouched for by <em>Certificate
 * Authorities</em> (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.
 * <p>
 * The ASN.1 definition of <code>tbsCertificate</code> is:
 * <pre>
 * TBSCertificate  ::=  SEQUENCE  {
 *     version         [0]  EXPLICIT Version DEFAULT v1,
 *     serialNumber         CertificateSerialNumber,
 *     signature            AlgorithmIdentifier,
 *     issuer               Name,
 *     validity             Validity,
 *     subject              Name,
 *     subjectPublicKeyInfo SubjectPublicKeyInfo,
 *     }
 * </pre>
 * <p>
 * Here is sample code to instantiate an X.509 certificate:
 * <pre>
 * InputStream inStream = new FileInputStream("fileName-of-cert");
 * X509Certificate cert = X509Certificate.getInstance(inStream);
 * inStream.close();
 * </pre>
 * OR
 * <pre>
 * byte[] certData = &lt;certificate read from a file, say&gt;
 * X509Certificate cert = X509Certificate.getInstance(certData);
 * </pre>
 * <p>
 * In either case, the code that instantiates an X.509 certificate
 * consults the Java security properties file to locate the actual
 * implementation or instantiates a default implementation.
 * <p>
 * The Java security properties file is located in the file named
 * &lt;JAVA_HOME&gt;/lib/security/java.security.
 * &lt;JAVA_HOME&gt; refers to the value of the java.home system property,
 * and specifies the directory where the JRE is installed.
 * In the Security properties file, a default implementation
 * for X.509 v1 may be given such as:
 * <pre>
 * cert.provider.x509v1=com.sun.security.cert.internal.x509.X509V1CertImpl
 * </pre>
 * <p>
 * The value of this <code>cert.provider.x509v1</code> property has to be
 * changed to instatiate another implementation. If this security
 * property is not set, a default implementation will be used.
 * Currently, due to possible security restrictions on access to
 * Security properties, this value is looked up and cached at class
 * initialization time and will fallback on a default implementation if
 * the Security property is not accessible.
 *
 * <p><em>Note: The classes in the package <code>javax.security.cert</code>
 * exist for compatibility with earlier versions of the
 * Java Secure Sockets Extension (JSSE). New applications should instead
 * use the standard Java SE certificate classes located in
 * <code>java.security.cert</code>.</em></p>
 *
 * @author Hemma Prafullchandra
 * @since 1.4
 * @see Certificate
 * @see java.security.cert.X509Extension
 */
public abstract class X509Certificate extends Certificate {

    /*
     * Constant to lookup in the Security properties file.
     * In the Security properties file the default implementation
     * for X.509 v3 is given as:
     * <pre>
     * cert.provider.x509v1=com.sun.security.cert.internal.x509.X509V1CertImpl
     * </pre>
     */
    private static final String X509_PROVIDER = "cert.provider.x509v1";
    private static String X509Provider;

    static {
        X509Provider = AccessController.doPrivileged(
            new PrivilegedAction<String>() {
                public String run() {
                    return Security.getProperty(X509_PROVIDER);
                }
            }
        );
    }

    
Instantiates an X509Certificate object, and initializes it with
the data read from the input stream inStream.
The implementation (X509Certificate is an abstract class) is
provided by the class specified as the value of the
cert.provider.x509v1
property in the security properties file.

Note: Only one DER-encoded
certificate is expected to be in the input stream.
Also, all X509Certificate
subclasses must provide a constructor of the form:

public <subClass>(InputStream inStream) ...



Params:
  • inStream – an input stream with the data to be read to
       initialize the certificate.
Throws:
Returns:an X509Certificate object initialized with the data
        from the input stream.
/**
     * Instantiates an X509Certificate object, and initializes it with
     * the data read from the input stream <code>inStream</code>.
     * The implementation (X509Certificate is an abstract class) is
     * provided by the class specified as the value of the
     * <code>cert.provider.x509v1</code>
     * property in the security properties file.
     *
     * <p>Note: Only one DER-encoded
     * certificate is expected to be in the input stream.
     * Also, all X509Certificate
     * subclasses must provide a constructor of the form:
     * <code><pre>
     * public &lt;subClass&gt;(InputStream inStream) ...
     * </pre></code>
     *
     * @param inStream an input stream with the data to be read to
     *        initialize the certificate.
     * @return an X509Certificate object initialized with the data
     *         from the input stream.
     * @exception CertificateException if a class initialization
     *            or certificate parsing error occurs.
     */
    public static final X509Certificate getInstance(InputStream inStream)
    throws CertificateException {
        return getInst((Object)inStream);
    }

    
Instantiates an X509Certificate object, and initializes it with
the specified byte array.
The implementation (X509Certificate is an abstract class) is
provided by the class specified as the value of the
cert.provider.x509v1
property in the security properties file.

Note: All X509Certificate
subclasses must provide a constructor of the form:

public <subClass>(InputStream inStream) ...



Params:
  • certData – a byte array containing the DER-encoded
       certificate.
Throws:
Returns:an X509Certificate object initialized with the data
        from certData.
/**
     * Instantiates an X509Certificate object, and initializes it with
     * the specified byte array.
     * The implementation (X509Certificate is an abstract class) is
     * provided by the class specified as the value of the
     * <code>cert.provider.x509v1</code>
     * property in the security properties file.
     *
     * <p>Note: All X509Certificate
     * subclasses must provide a constructor of the form:
     * <code><pre>
     * public &lt;subClass&gt;(InputStream inStream) ...
     * </pre></code>
     *
     * @param certData a byte array containing the DER-encoded
     *        certificate.
     * @return an X509Certificate object initialized with the data
     *         from <code>certData</code>.
     * @exception CertificateException if a class initialization
     *            or certificate parsing error occurs.
     */
    public static final X509Certificate getInstance(byte[] certData)
    throws CertificateException {
        return getInst((Object)certData);
    }

    private static final X509Certificate getInst(Object value)
    throws CertificateException {
        /*
         * This turns out not to work for now. To run under JDK1.2 we would
         * need to call beginPrivileged() but we can't do that and run
         * under JDK1.1.
         */
        String className = X509Provider;
        if (className == null || className.length() == 0) {
            // shouldn't happen, but assume corrupted properties file
            // provide access to sun implementation
            className = "com.sun.security.cert.internal.x509.X509V1CertImpl";
        }
        try {
            Class[] params = null;
            if (value instanceof InputStream) {
                params = new Class[] { InputStream.class };
            } else if (value instanceof byte[]) {
                params = new Class[] { value.getClass() };
            } else
                throw new CertificateException("Unsupported argument type");
            Class<?> certClass = Class.forName(className);

            // get the appropriate constructor and instantiate it
            Constructor<?> cons = certClass.getConstructor(params);

            // get a new instance
            Object obj = cons.newInstance(new Object[] {value});
            return (X509Certificate)obj;

        } catch (ClassNotFoundException e) {
          throw new CertificateException("Could not find class: " + e);
        } catch (IllegalAccessException e) {
          throw new CertificateException("Could not access class: " + e);
        } catch (InstantiationException e) {
          throw new CertificateException("Problems instantiating: " + e);
        } catch (InvocationTargetException e) {
          throw new CertificateException("InvocationTargetException: "
                                         + e.getTargetException());
        } catch (NoSuchMethodException e) {
          throw new CertificateException("Could not find class method: "
                                          + e.getMessage());
        }
    }

    
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:
/**
     * Checks that the certificate is currently valid. It is if
     * the current date and time are within the validity period given in the
     * certificate.
     * <p>
     * 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:
     * <pre>
     * validity             Validity<p>
     * Validity ::= SEQUENCE {
     *     notBefore      CertificateValidityDate,
     *     notAfter       CertificateValidityDate }<p>
     * CertificateValidityDate ::= CHOICE {
     *     utcTime        UTCTime,
     *     generalTime    GeneralizedTime }
     * </pre>
     *
     * @exception CertificateExpiredException if the certificate has expired.
     * @exception CertificateNotYetValidException if the certificate is not
     *            yet valid.
     */
    public abstract void checkValidity()
        throws CertificateExpiredException, CertificateNotYetValidException;

    
Checks that the specified date is within the certificate's
validity period. In other words, this determines whether the
certificate would be valid at the specified date/time.

Params:
  • date – the Date to check against to see if this certificate
       is valid at that date/time.
Throws:
See Also:
/**
     * Checks that the specified date is within the certificate's
     * validity period. In other words, this determines whether the
     * certificate would be valid at the specified date/time.
     *
     * @param date the Date to check against to see if this certificate
     *        is valid at that date/time.
     * @exception CertificateExpiredException if the certificate has expired
     *            with respect to the <code>date</code> supplied.
     * @exception CertificateNotYetValidException if the certificate is not
     *            yet valid with respect to the <code>date</code> supplied.
     * @see #checkValidity()
     */
    public abstract void checkValidity(Date date)
        throws CertificateExpiredException, CertificateNotYetValidException;

    
Gets the version (version number) value from the
certificate. The ASN.1 definition for this is:

version         [0]  EXPLICIT Version DEFAULT v1

Version  ::=  INTEGER  {  v1(0), v2(1), v3(2)  }



Returns:the version number from the ASN.1 encoding, i.e. 0, 1 or 2.
/**
     * Gets the <code>version</code> (version number) value from the
     * certificate. The ASN.1 definition for this is:
     * <pre>
     * version         [0]  EXPLICIT Version DEFAULT v1<p>
     * Version  ::=  INTEGER  {  v1(0), v2(1), v3(2)  }
     * </pre>
     *
     * @return the version number from the ASN.1 encoding, i.e. 0, 1 or 2.
     */
    public abstract int getVersion();

    
Gets the serialNumber value from the certificate.
The serial number is an integer assigned by the certification
authority to each certificate. It must be unique for each
certificate issued by a given CA (i.e., the issuer name and
serial number identify a unique certificate).
The ASN.1 definition for this is:

serialNumber     CertificateSerialNumber

CertificateSerialNumber  ::=  INTEGER



Returns:the serial number.
/**
     * Gets the <code>serialNumber</code> value from the certificate.
     * The serial number is an integer assigned by the certification
     * authority to each certificate. It must be unique for each
     * certificate issued by a given CA (i.e., the issuer name and
     * serial number identify a unique certificate).
     * The ASN.1 definition for this is:
     * <pre>
     * serialNumber     CertificateSerialNumber<p>
     *
     * CertificateSerialNumber  ::=  INTEGER
     * </pre>
     *
     * @return the serial number.
     */
    public abstract BigInteger getSerialNumber();

    
Gets the issuer (issuer distinguished name) value from
the certificate. The issuer name identifies the entity that signed (and
issued) the certificate.

The issuer name field contains an
X.500 distinguished name (DN).
The ASN.1 definition for this is:

issuer    Name

Name ::= CHOICE { RDNSequence }
RDNSequence ::= SEQUENCE OF RelativeDistinguishedName
RelativeDistinguishedName ::=
    SET OF AttributeValueAssertion
AttributeValueAssertion ::= SEQUENCE {
                              AttributeType,
                              AttributeValue }
AttributeType ::= OBJECT IDENTIFIER
AttributeValue ::= ANY


The Name describes a hierarchical name composed of
attributes, such as country name, and corresponding values, such as US.
The type of the AttributeValue component is determined by
the AttributeType; in general it will be a
directoryString. A directoryString is usually
one of PrintableString,
TeletexString or UniversalString.

Returns:a Principal whose name is the issuer distinguished name.
/**
     * Gets the <code>issuer</code> (issuer distinguished name) value from
     * the certificate. The issuer name identifies the entity that signed (and
     * issued) the certificate.
     *
     * <p>The issuer name field contains an
     * X.500 distinguished name (DN).
     * The ASN.1 definition for this is:
     * <pre>
     * issuer    Name<p>
     *
     * Name ::= CHOICE { RDNSequence }
     * RDNSequence ::= SEQUENCE OF RelativeDistinguishedName
     * RelativeDistinguishedName ::=
     *     SET OF AttributeValueAssertion
     *
     * AttributeValueAssertion ::= SEQUENCE {
     *                               AttributeType,
     *                               AttributeValue }
     * AttributeType ::= OBJECT IDENTIFIER
     * AttributeValue ::= ANY
     * </pre>
     * The <code>Name</code> describes a hierarchical name composed of
     * attributes, such as country name, and corresponding values, such as US.
     * The type of the <code>AttributeValue</code> component is determined by
     * the <code>AttributeType</code>; in general it will be a
     * <code>directoryString</code>. A <code>directoryString</code> is usually
     * one of <code>PrintableString</code>,
     * <code>TeletexString</code> or <code>UniversalString</code>.
     *
     * @return a Principal whose name is the issuer distinguished name.
     */
    public abstract Principal getIssuerDN();

    
Gets the subject (subject distinguished name) value
from the certificate.
The ASN.1 definition for this is:

subject    Name



See getIssuerDN for Name
and other relevant definitions.

See Also:
Returns:a Principal whose name is the subject name.
/**
     * Gets the <code>subject</code> (subject distinguished name) value
     * from the certificate.
     * The ASN.1 definition for this is:
     * <pre>
     * subject    Name
     * </pre>
     *
     * <p>See <a href = "#getIssuerDN">getIssuerDN</a> for <code>Name</code>
     * and other relevant definitions.
     *
     * @return a Principal whose name is the subject name.
     * @see #getIssuerDN()
     */
    public abstract Principal getSubjectDN();

    
Gets the notBefore date from the validity period of
the certificate.
The relevant ASN.1 definitions are:

validity             Validity

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

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



See Also:
Returns:the start date of the validity period.
/**
     * Gets the <code>notBefore</code> date from the validity period of
     * the certificate.
     * The relevant ASN.1 definitions are:
     * <pre>
     * validity             Validity<p>
     *
     * Validity ::= SEQUENCE {
     *     notBefore      CertificateValidityDate,
     *     notAfter       CertificateValidityDate }<p>
     * CertificateValidityDate ::= CHOICE {
     *     utcTime        UTCTime,
     *     generalTime    GeneralizedTime }
     * </pre>
     *
     * @return the start date of the validity period.
     * @see #checkValidity()
     */
    public abstract Date getNotBefore();

    
Gets the notAfter date from the validity period of
the certificate. See getNotBefore
for relevant ASN.1 definitions.

See Also:
Returns:the end date of the validity period.
/**
     * Gets the <code>notAfter</code> date from the validity period of
     * the certificate. See <a href = "#getNotBefore">getNotBefore</a>
     * for relevant ASN.1 definitions.
     *
     * @return the end date of the validity period.
     * @see #checkValidity()
     */
    public abstract Date getNotAfter();

    
Gets the signature algorithm name for the certificate
signature algorithm. An example is the string "SHA-1/DSA".
The ASN.1 definition for this is:

signatureAlgorithm   AlgorithmIdentifier

AlgorithmIdentifier  ::=  SEQUENCE  {
    algorithm               OBJECT IDENTIFIER,
    parameters              ANY DEFINED BY algorithm OPTIONAL  }
                            -- contains a value of the type
                            -- registered for use with the
                            -- algorithm object identifier value



The algorithm name is determined from the algorithm
OID string.

Returns:the signature algorithm name.
/**
     * Gets the signature algorithm name for the certificate
     * signature algorithm. An example is the string "SHA-1/DSA".
     * The ASN.1 definition for this is:
     * <pre>
     * signatureAlgorithm   AlgorithmIdentifier<p>
     * AlgorithmIdentifier  ::=  SEQUENCE  {
     *     algorithm               OBJECT IDENTIFIER,
     *     parameters              ANY DEFINED BY algorithm OPTIONAL  }
     *                             -- contains a value of the type
     *                             -- registered for use with the
     *                             -- algorithm object identifier value
     * </pre>
     *
     * <p>The algorithm name is determined from the <code>algorithm</code>
     * OID string.
     *
     * @return the signature algorithm name.
     */
    public abstract String getSigAlgName();

    
Gets the signature algorithm OID string from the certificate.
An OID is represented by a set of positive whole numbers separated
by periods.
For example, the string "1.2.840.10040.4.3" identifies the SHA-1
with DSA signature algorithm, as per the PKIX part I.

See getSigAlgName for
relevant ASN.1 definitions.

Returns:the signature algorithm OID string.
/**
     * Gets the signature algorithm OID string from the certificate.
     * An OID is represented by a set of positive whole numbers separated
     * by periods.
     * For example, the string "1.2.840.10040.4.3" identifies the SHA-1
     * with DSA signature algorithm, as per the PKIX part I.
     *
     * <p>See <a href = "#getSigAlgName">getSigAlgName</a> for
     * relevant ASN.1 definitions.
     *
     * @return the signature algorithm OID string.
     */
    public abstract String getSigAlgOID();

    
Gets the DER-encoded signature algorithm parameters from this
certificate's signature algorithm. In most cases, the signature
algorithm parameters are null; the parameters are usually
supplied with the certificate's public key.

See getSigAlgName for
relevant ASN.1 definitions.

Returns:the DER-encoded signature algorithm parameters, or
        null if no parameters are present.
/**
     * Gets the DER-encoded signature algorithm parameters from this
     * certificate's signature algorithm. In most cases, the signature
     * algorithm parameters are null; the parameters are usually
     * supplied with the certificate's public key.
     *
     * <p>See <a href = "#getSigAlgName">getSigAlgName</a> for
     * relevant ASN.1 definitions.
     *
     * @return the DER-encoded signature algorithm parameters, or
     *         null if no parameters are present.
     */
    public abstract byte[] getSigAlgParams();
}