src/java.base/share/classes/java/security/cert/X509Certificate.java
changeset 47216 71c04702a3d5
parent 45474 78b7a8c8fc06
child 50204 3195a713e24d
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.base/share/classes/java/security/cert/X509Certificate.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,689 @@
+/*
+ * Copyright (c) 1997, 2017, 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 java.security.cert;
+
+import java.math.BigInteger;
+import java.security.*;
+import java.util.Collection;
+import java.util.Date;
+import java.util.List;
+import javax.security.auth.x500.X500Principal;
+
+import sun.security.x509.X509CertImpl;
+
+/**
+ * <p>
+ * Abstract class for X.509 certificates. This provides a standard
+ * way to access all the attributes of an X.509 certificate.
+ * <p>
+ * 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:
+ * <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>
+ * More information can be found in
+ * <a href="http://tools.ietf.org/html/rfc5280">RFC 5280: Internet X.509
+ * Public Key Infrastructure Certificate and CRL Profile</a>.
+ * <p>
+ * The ASN.1 definition of {@code tbsCertificate} is:
+ * <pre>
+ * 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
+ *     }
+ * </pre>
+ * <p>
+ * Certificates are instantiated using a certificate factory. The following is
+ * an example of how to instantiate an X.509 certificate:
+ * <pre>
+ * try (InputStream inStream = new FileInputStream("fileName-of-cert")) {
+ *     CertificateFactory cf = CertificateFactory.getInstance("X.509");
+ *     X509Certificate cert = (X509Certificate)cf.generateCertificate(inStream);
+ * }
+ * </pre>
+ *
+ * @author Hemma Prafullchandra
+ * @since 1.2
+ *
+ *
+ * @see Certificate
+ * @see CertificateFactory
+ * @see X509Extension
+ */
+
+public abstract class X509Certificate extends Certificate
+implements X509Extension {
+
+    private static final long serialVersionUID = -2491127588187038216L;
+
+    private transient X500Principal subjectX500Principal, issuerX500Principal;
+
+    /**
+     * Constructor for X.509 certificates.
+     */
+    protected X509Certificate() {
+        super("X.509");
+    }
+
+    /**
+     * 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
+     *
+     * Validity ::= SEQUENCE {
+     *     notBefore      CertificateValidityDate,
+     *     notAfter       CertificateValidityDate }
+     *
+     * 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 given date is within the certificate's
+     * validity period. In other words, this determines whether the
+     * certificate would be valid at the given 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} supplied.
+     * @exception CertificateNotYetValidException if the certificate is not
+     * yet valid with respect to the {@code date} supplied.
+     *
+     * @see #checkValidity()
+     */
+    public abstract void checkValidity(Date date)
+        throws CertificateExpiredException, CertificateNotYetValidException;
+
+    /**
+     * Gets the {@code version} (version number) value from the
+     * certificate.
+     * The ASN.1 definition for this is:
+     * <pre>
+     * version  [0] EXPLICIT Version DEFAULT v1
+     *
+     * Version ::=  INTEGER  {  v1(0), v2(1), v3(2)  }
+     * </pre>
+     * @return the version number, i.e. 1, 2 or 3.
+     */
+    public abstract int getVersion();
+
+    /**
+     * Gets the {@code 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:
+     * <pre>
+     * serialNumber     CertificateSerialNumber
+     *
+     * CertificateSerialNumber  ::=  INTEGER
+     * </pre>
+     *
+     * @return the serial number.
+     */
+    public abstract BigInteger getSerialNumber();
+
+    /**
+     * <strong>Denigrated</strong>, replaced by {@linkplain
+     * #getIssuerX500Principal()}. This method returns the {@code issuer}
+     * as an implementation specific Principal object, which should not be
+     * relied upon by portable code.
+     *
+     * <p>
+     * Gets the {@code issuer} (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
+     *
+     * Name ::= CHOICE { RDNSequence }
+     * RDNSequence ::= SEQUENCE OF RelativeDistinguishedName
+     * RelativeDistinguishedName ::=
+     *     SET OF AttributeValueAssertion
+     *
+     * AttributeValueAssertion ::= SEQUENCE {
+     *                               AttributeType,
+     *                               AttributeValue }
+     * AttributeType ::= OBJECT IDENTIFIER
+     * AttributeValue ::= ANY
+     * </pre>
+     * The {@code Name} describes a hierarchical name composed of
+     * attributes,
+     * such as country name, and corresponding values, such as US.
+     * The type of the {@code AttributeValue} component is determined by
+     * the {@code AttributeType}; in general it will be a
+     * {@code directoryString}. A {@code directoryString} is usually
+     * one of {@code PrintableString},
+     * {@code TeletexString} or {@code UniversalString}.
+     *
+     * @return a Principal whose name is the issuer distinguished name.
+     */
+    public abstract Principal getIssuerDN();
+
+    /**
+     * Returns the issuer (issuer distinguished name) value from the
+     * certificate as an {@code X500Principal}.
+     * <p>
+     * It is recommended that subclasses override this method.
+     *
+     * @return an {@code X500Principal} representing the issuer
+     *          distinguished name
+     * @since 1.4
+     */
+    public X500Principal getIssuerX500Principal() {
+        if (issuerX500Principal == null) {
+            issuerX500Principal = X509CertImpl.getIssuerX500Principal(this);
+        }
+        return issuerX500Principal;
+    }
+
+    /**
+     * <strong>Denigrated</strong>, replaced by {@linkplain
+     * #getSubjectX500Principal()}. This method returns the {@code subject}
+     * as an implementation specific Principal object, which should not be
+     * relied upon by portable code.
+     *
+     * <p>
+     * Gets the {@code subject} (subject distinguished name) value
+     * from the certificate.  If the {@code subject} value is empty,
+     * then the {@code getName()} method of the returned
+     * {@code Principal} object returns an empty string ("").
+     *
+     * <p> The ASN.1 definition for this is:
+     * <pre>
+     * subject    Name
+     * </pre>
+     *
+     * <p>See {@link #getIssuerDN() getIssuerDN} for {@code Name}
+     * and other relevant definitions.
+     *
+     * @return a Principal whose name is the subject name.
+     */
+    public abstract Principal getSubjectDN();
+
+    /**
+     * Returns the subject (subject distinguished name) value from the
+     * certificate as an {@code X500Principal}.  If the subject value
+     * is empty, then the {@code getName()} method of the returned
+     * {@code X500Principal} object returns an empty string ("").
+     * <p>
+     * It is recommended that subclasses override this method.
+     *
+     * @return an {@code X500Principal} representing the subject
+     *          distinguished name
+     * @since 1.4
+     */
+    public X500Principal getSubjectX500Principal() {
+        if (subjectX500Principal == null) {
+            subjectX500Principal = X509CertImpl.getSubjectX500Principal(this);
+        }
+        return subjectX500Principal;
+    }
+
+    /**
+     * Gets the {@code notBefore} date from the validity period of
+     * the certificate.
+     * The relevant ASN.1 definitions are:
+     * <pre>
+     * validity             Validity
+     *
+     * Validity ::= SEQUENCE {
+     *     notBefore      CertificateValidityDate,
+     *     notAfter       CertificateValidityDate }
+     *
+     * CertificateValidityDate ::= CHOICE {
+     *     utcTime        UTCTime,
+     *     generalTime    GeneralizedTime }
+     * </pre>
+     *
+     * @return the start date of the validity period.
+     * @see #checkValidity
+     */
+    public abstract Date getNotBefore();
+
+    /**
+     * Gets the {@code notAfter} date from the validity period of
+     * the certificate. See {@link #getNotBefore() getNotBefore}
+     * for relevant ASN.1 definitions.
+     *
+     * @return the end date of the validity period.
+     * @see #checkValidity
+     */
+    public abstract Date getNotAfter();
+
+    /**
+     * Gets the DER-encoded certificate information, the
+     * {@code tbsCertificate} from this certificate.
+     * This can be used to verify the signature independently.
+     *
+     * @return the DER-encoded certificate information.
+     * @exception CertificateEncodingException if an encoding error occurs.
+     */
+    public abstract byte[] getTBSCertificate()
+        throws CertificateEncodingException;
+
+    /**
+     * Gets the {@code signature} value (the raw signature bits) from
+     * the certificate.
+     * The ASN.1 definition for this is:
+     * <pre>
+     * signature     BIT STRING
+     * </pre>
+     *
+     * @return the signature.
+     */
+    public abstract byte[] getSignature();
+
+    /**
+     * Gets the signature algorithm name for the certificate
+     * signature algorithm. An example is the string "SHA256withRSA".
+     * The ASN.1 definition for this is:
+     * <pre>
+     * 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
+     * </pre>
+     *
+     * <p>The algorithm name is determined from the {@code algorithm}
+     * 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 nonnegative whole numbers separated
+     * by periods.
+     * For example, the string "1.2.840.10040.4.3" identifies the SHA-1
+     * with DSA signature algorithm defined in
+     * <a href="http://www.ietf.org/rfc/rfc3279.txt">RFC 3279: Algorithms and
+     * Identifiers for the Internet X.509 Public Key Infrastructure Certificate
+     * and CRL Profile</a>.
+     *
+     * <p>See {@link #getSigAlgName() getSigAlgName} 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.
+     * If access to individual parameter values is needed then use
+     * {@link java.security.AlgorithmParameters AlgorithmParameters}
+     * and instantiate with the name returned by
+     * {@link #getSigAlgName() getSigAlgName}.
+     *
+     * <p>See {@link #getSigAlgName() getSigAlgName} for
+     * relevant ASN.1 definitions.
+     *
+     * @return the DER-encoded signature algorithm parameters, or
+     *         null if no parameters are present.
+     */
+    public abstract byte[] getSigAlgParams();
+
+    /**
+     * Gets the {@code issuerUniqueID} value from the certificate.
+     * The issuer unique identifier is present in the certificate
+     * to handle the possibility of reuse of issuer names over time.
+     * RFC 5280 recommends that names not be reused and that
+     * conforming certificates not make use of unique identifiers.
+     * Applications conforming to that profile should be capable of
+     * parsing unique identifiers and making comparisons.
+     *
+     * <p>The ASN.1 definition for this is:
+     * <pre>
+     * issuerUniqueID  [1]  IMPLICIT UniqueIdentifier OPTIONAL
+     *
+     * UniqueIdentifier  ::=  BIT STRING
+     * </pre>
+     *
+     * @return the issuer unique identifier or null if it is not
+     * present in the certificate.
+     */
+    public abstract boolean[] getIssuerUniqueID();
+
+    /**
+     * Gets the {@code subjectUniqueID} value from the certificate.
+     *
+     * <p>The ASN.1 definition for this is:
+     * <pre>
+     * subjectUniqueID  [2]  IMPLICIT UniqueIdentifier OPTIONAL
+     *
+     * UniqueIdentifier  ::=  BIT STRING
+     * </pre>
+     *
+     * @return the subject unique identifier or null if it is not
+     * present in the certificate.
+     */
+    public abstract boolean[] getSubjectUniqueID();
+
+    /**
+     * Gets a boolean array representing bits of
+     * the {@code KeyUsage} extension, (OID = 2.5.29.15).
+     * The key usage extension defines the purpose (e.g., encipherment,
+     * signature, certificate signing) of the key contained in the
+     * certificate.
+     * The ASN.1 definition for this is:
+     * <pre>
+     * KeyUsage ::= BIT STRING {
+     *     digitalSignature        (0),
+     *     nonRepudiation          (1),
+     *     keyEncipherment         (2),
+     *     dataEncipherment        (3),
+     *     keyAgreement            (4),
+     *     keyCertSign             (5),
+     *     cRLSign                 (6),
+     *     encipherOnly            (7),
+     *     decipherOnly            (8) }
+     * </pre>
+     * RFC 5280 recommends that when used, this be marked
+     * as a critical extension.
+     *
+     * @return the KeyUsage extension of this certificate, represented as
+     * an array of booleans. The order of KeyUsage values in the array is
+     * the same as in the above ASN.1 definition. The array will contain a
+     * value for each KeyUsage defined above. If the KeyUsage list encoded
+     * in the certificate is longer than the above list, it will not be
+     * truncated. Returns null if this certificate does not
+     * contain a KeyUsage extension.
+     */
+    public abstract boolean[] getKeyUsage();
+
+    /**
+     * Gets an unmodifiable list of Strings representing the OBJECT
+     * IDENTIFIERs of the {@code ExtKeyUsageSyntax} field of the
+     * extended key usage extension, (OID = 2.5.29.37).  It indicates
+     * one or more purposes for which the certified public key may be
+     * used, in addition to or in place of the basic purposes
+     * indicated in the key usage extension field.  The ASN.1
+     * definition for this is:
+     * <pre>
+     * ExtKeyUsageSyntax ::= SEQUENCE SIZE (1..MAX) OF KeyPurposeId
+     *
+     * KeyPurposeId ::= OBJECT IDENTIFIER
+     * </pre>
+     *
+     * Key purposes may be defined by any organization with a
+     * need. Object identifiers used to identify key purposes shall be
+     * assigned in accordance with IANA or ITU-T Rec. X.660 |
+     * ISO/IEC/ITU 9834-1.
+     * <p>
+     * This method was added to version 1.4 of the Java 2 Platform Standard
+     * Edition. In order to maintain backwards compatibility with existing
+     * service providers, this method is not {@code abstract}
+     * and it provides a default implementation. Subclasses
+     * should override this method with a correct implementation.
+     *
+     * @return the ExtendedKeyUsage extension of this certificate,
+     *         as an unmodifiable list of object identifiers represented
+     *         as Strings. Returns null if this certificate does not
+     *         contain an ExtendedKeyUsage extension.
+     * @throws CertificateParsingException if the extension cannot be decoded
+     * @since 1.4
+     */
+    public List<String> getExtendedKeyUsage() throws CertificateParsingException {
+        return X509CertImpl.getExtendedKeyUsage(this);
+    }
+
+    /**
+     * Gets the certificate constraints path length from the
+     * critical {@code BasicConstraints} extension, (OID = 2.5.29.19).
+     * <p>
+     * The basic constraints extension identifies whether the subject
+     * of the certificate is a Certificate Authority (CA) and
+     * how deep a certification path may exist through that CA. The
+     * {@code pathLenConstraint} field (see below) is meaningful
+     * only if {@code cA} is set to TRUE. In this case, it gives the
+     * maximum number of CA certificates that may follow this certificate in a
+     * certification path. A value of zero indicates that only an end-entity
+     * certificate may follow in the path.
+     * <p>
+     * The ASN.1 definition for this is:
+     * <pre>
+     * BasicConstraints ::= SEQUENCE {
+     *     cA                  BOOLEAN DEFAULT FALSE,
+     *     pathLenConstraint   INTEGER (0..MAX) OPTIONAL }
+     * </pre>
+     *
+     * @return the value of {@code pathLenConstraint} if the
+     * BasicConstraints extension is present in the certificate and the
+     * subject of the certificate is a CA, otherwise -1.
+     * If the subject of the certificate is a CA and
+     * {@code pathLenConstraint} does not appear,
+     * {@code Integer.MAX_VALUE} is returned to indicate that there is no
+     * limit to the allowed length of the certification path.
+     */
+    public abstract int getBasicConstraints();
+
+    /**
+     * Gets an immutable collection of subject alternative names from the
+     * {@code SubjectAltName} extension, (OID = 2.5.29.17).
+     * <p>
+     * The ASN.1 definition of the {@code SubjectAltName} extension is:
+     * <pre>
+     * SubjectAltName ::= GeneralNames
+     *
+     * GeneralNames :: = SEQUENCE SIZE (1..MAX) OF GeneralName
+     *
+     * GeneralName ::= CHOICE {
+     *      otherName                       [0]     OtherName,
+     *      rfc822Name                      [1]     IA5String,
+     *      dNSName                         [2]     IA5String,
+     *      x400Address                     [3]     ORAddress,
+     *      directoryName                   [4]     Name,
+     *      ediPartyName                    [5]     EDIPartyName,
+     *      uniformResourceIdentifier       [6]     IA5String,
+     *      iPAddress                       [7]     OCTET STRING,
+     *      registeredID                    [8]     OBJECT IDENTIFIER}
+     * </pre>
+     * <p>
+     * If this certificate does not contain a {@code SubjectAltName}
+     * extension, {@code null} is returned. Otherwise, a
+     * {@code Collection} is returned with an entry representing each
+     * {@code GeneralName} included in the extension. Each entry is a
+     * {@code List} whose first entry is an {@code Integer}
+     * (the name type, 0-8) and whose second entry is a {@code String}
+     * or a byte array (the name, in string or ASN.1 DER encoded form,
+     * respectively).
+     * <p>
+     * <a href="http://www.ietf.org/rfc/rfc822.txt">RFC 822</a>, DNS, and URI
+     * names are returned as {@code String}s,
+     * using the well-established string formats for those types (subject to
+     * the restrictions included in RFC 5280). IPv4 address names are
+     * returned using dotted quad notation. IPv6 address names are returned
+     * in the form "a1:a2:...:a8", where a1-a8 are hexadecimal values
+     * representing the eight 16-bit pieces of the address. OID names are
+     * returned as {@code String}s represented as a series of nonnegative
+     * integers separated by periods. And directory names (distinguished names)
+     * are returned in <a href="http://www.ietf.org/rfc/rfc2253.txt">
+     * RFC 2253</a> string format. No standard string format is
+     * defined for otherNames, X.400 names, EDI party names, or any
+     * other type of names. They are returned as byte arrays
+     * containing the ASN.1 DER encoded form of the name.
+     * <p>
+     * Note that the {@code Collection} returned may contain more
+     * than one name of the same type. Also, note that the returned
+     * {@code Collection} is immutable and any entries containing byte
+     * arrays are cloned to protect against subsequent modifications.
+     * <p>
+     * This method was added to version 1.4 of the Java 2 Platform Standard
+     * Edition. In order to maintain backwards compatibility with existing
+     * service providers, this method is not {@code abstract}
+     * and it provides a default implementation. Subclasses
+     * should override this method with a correct implementation.
+     *
+     * @return an immutable {@code Collection} of subject alternative
+     * names (or {@code null})
+     * @throws CertificateParsingException if the extension cannot be decoded
+     * @since 1.4
+     */
+    public Collection<List<?>> getSubjectAlternativeNames()
+        throws CertificateParsingException {
+        return X509CertImpl.getSubjectAlternativeNames(this);
+    }
+
+    /**
+     * Gets an immutable collection of issuer alternative names from the
+     * {@code IssuerAltName} extension, (OID = 2.5.29.18).
+     * <p>
+     * The ASN.1 definition of the {@code IssuerAltName} extension is:
+     * <pre>
+     * IssuerAltName ::= GeneralNames
+     * </pre>
+     * The ASN.1 definition of {@code GeneralNames} is defined
+     * in {@link #getSubjectAlternativeNames getSubjectAlternativeNames}.
+     * <p>
+     * If this certificate does not contain an {@code IssuerAltName}
+     * extension, {@code null} is returned. Otherwise, a
+     * {@code Collection} is returned with an entry representing each
+     * {@code GeneralName} included in the extension. Each entry is a
+     * {@code List} whose first entry is an {@code Integer}
+     * (the name type, 0-8) and whose second entry is a {@code String}
+     * or a byte array (the name, in string or ASN.1 DER encoded form,
+     * respectively). For more details about the formats used for each
+     * name type, see the {@code getSubjectAlternativeNames} method.
+     * <p>
+     * Note that the {@code Collection} returned may contain more
+     * than one name of the same type. Also, note that the returned
+     * {@code Collection} is immutable and any entries containing byte
+     * arrays are cloned to protect against subsequent modifications.
+     * <p>
+     * This method was added to version 1.4 of the Java 2 Platform Standard
+     * Edition. In order to maintain backwards compatibility with existing
+     * service providers, this method is not {@code abstract}
+     * and it provides a default implementation. Subclasses
+     * should override this method with a correct implementation.
+     *
+     * @return an immutable {@code Collection} of issuer alternative
+     * names (or {@code null})
+     * @throws CertificateParsingException if the extension cannot be decoded
+     * @since 1.4
+     */
+    public Collection<List<?>> getIssuerAlternativeNames()
+        throws CertificateParsingException {
+        return X509CertImpl.getIssuerAlternativeNames(this);
+    }
+
+    /**
+     * Verifies that this certificate was signed using the
+     * private key that corresponds to the specified public key.
+     * This method uses the signature verification engine
+     * supplied by the specified provider. Note that the specified
+     * Provider object does not have to be registered in the provider list.
+     *
+     * This method was added to version 1.8 of the Java Platform Standard
+     * Edition. In order to maintain backwards compatibility with existing
+     * service providers, this method is not {@code abstract}
+     * and it provides a default implementation.
+     *
+     * @param key the PublicKey used to carry out the verification.
+     * @param sigProvider the signature provider.
+     *
+     * @exception NoSuchAlgorithmException on unsupported signature
+     * algorithms.
+     * @exception InvalidKeyException on incorrect key.
+     * @exception SignatureException on signature errors.
+     * @exception CertificateException on encoding errors.
+     * @exception UnsupportedOperationException if the method is not supported
+     * @since 1.8
+     */
+    public void verify(PublicKey key, Provider sigProvider)
+        throws CertificateException, NoSuchAlgorithmException,
+        InvalidKeyException, SignatureException {
+        Signature sig = (sigProvider == null)
+            ? Signature.getInstance(getSigAlgName())
+            : Signature.getInstance(getSigAlgName(), sigProvider);
+        sig.initVerify(key);
+
+        byte[] tbsCert = getTBSCertificate();
+        sig.update(tbsCert, 0, tbsCert.length);
+
+        if (sig.verify(getSignature()) == false) {
+            throw new SignatureException("Signature does not match.");
+        }
+    }
+}