Java tutorial
/* * Copyright (c) 1997, 2019, 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.security.spec.*; import java.util.Collection; import java.util.Date; import java.util.List; import javax.security.auth.x500.X500Principal; import sun.security.x509.X509CertImpl; import sun.security.util.SignatureUtil; /** * <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 { String sigName = getSigAlgName(); Signature sig = (sigProvider == null) ? Signature.getInstance(sigName) : Signature.getInstance(sigName, sigProvider); try { SignatureUtil.initVerifyWithParam(sig, key, SignatureUtil.getParamSpec(sigName, getSigAlgParams())); } catch (ProviderException e) { throw new CertificateException(e.getMessage(), e.getCause()); } catch (InvalidAlgorithmParameterException e) { throw new CertificateException(e); } byte[] tbsCert = getTBSCertificate(); sig.update(tbsCert, 0, tbsCert.length); if (sig.verify(getSignature()) == false) { throw new SignatureException("Signature does not match."); } } }