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Java(TM) 2 Platform, Standard Edition, v1.2.2 API Specification: Class X509CRL - JDK 5 Documentation v1.2.2, Java 2 SDK 英文文档

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java.security.cert
Class X509CRL

java.lang.Object
  |
  +--java.security.cert.CRL
        |
        +--java.security.cert.X509CRL
public abstract class X509CRL
extends CRL
implements X509Extension

Abstract class for an X.509 Certificate Revocation List (CRL). A CRL is a time-stamped list identifying revoked certificates. It is signed by a Certificate Authority (CA) and made freely available in a public repository.

Each revoked certificate is identified in a CRL by its certificate serial number. When a certificate-using system uses a certificate (e.g., for verifying a remote user's digital signature), that system not only checks the certificate signature and validity but also acquires a suitably- recent CRL and checks that the certificate serial number is not on that CRL. The meaning of "suitably-recent" may vary with local policy, but it usually means the most recently-issued CRL. A CA issues a new CRL on a regular periodic basis (e.g., hourly, daily, or weekly). Entries are added to CRLs as revocations occur, and an entry may be removed when the certificate expiration date is reached.

The X.509 v2 CRL format is described below in ASN.1: 

 CertificateList  ::=  SEQUENCE  {
     tbsCertList          TBSCertList,
     signatureAlgorithm   AlgorithmIdentifier,
     signature            BIT STRING  }

A good decription and profiling is provided in the IETF PKIX WG draft, Part I: X.509 Certificate and CRL Profile, <draft-ietf-pkix-ipki-part1-07.txt>.

The ASN.1 definition of tbsCertList is: 

 TBSCertList  ::=  SEQUENCE  {
     version                 Version OPTIONAL,
                             -- if present, must be v2
     signature               AlgorithmIdentifier,
     issuer                  Name,
     thisUpdate              ChoiceOfTime,
     nextUpdate              ChoiceOfTime OPTIONAL,
     revokedCertificates     SEQUENCE OF SEQUENCE  {
         userCertificate         CertificateSerialNumber,
         revocationDate          ChoiceOfTime,
         crlEntryExtensions      Extensions OPTIONAL
                                 -- if present, must be v2
         }  OPTIONAL,
     crlExtensions           [0]  EXPLICIT Extensions OPTIONAL
                                  -- if present, must be v2
     }

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

 
 InputStream inStream = new FileInputStream("fileName-of-crl");
 CertificateFactory cf = CertificateFactory.getInstance("X.509");
 X509CRL crl = (X509CRL)cf.generateCRL(inStream);
 inStream.close();

See Also:
CRL, CertificateFactory, X509Extension

Constructor Summary
protected X509CRL()
          Constructor for X.509 CRLs.
 
Method Summary
 boolean equals(Object other)
          Compares this CRL for equality with the given object.
abstract  byte[] getEncoded()
          Returns the ASN.1 DER-encoded form of this CRL.
abstract  Principal getIssuerDN()
          Gets the issuer (issuer distinguished name) value from the CRL.
abstract  Date getNextUpdate()
          Gets the nextUpdate date from the CRL.
abstract  X509CRLEntry getRevokedCertificate(BigInteger serialNumber)
          Gets the CRL entry with the given serialNumber from this CRL.
abstract  Set getRevokedCertificates()
          Gets all the entries from this CRL.
abstract  String getSigAlgName()
          Gets the signature algorithm name for the CRL signature algorithm.
abstract  String getSigAlgOID()
          Gets the signature algorithm OID string from the CRL.
abstract  byte[] getSigAlgParams()
          Gets the DER-encoded signature algorithm parameters from this CRL's signature algorithm.
abstract  byte[] getSignature()
          Gets the signature value (the raw signature bits) from the CRL.
abstract  byte[] getTBSCertList()
          Gets the DER-encoded CRL information, the tbsCertList from this CRL.
abstract  Date getThisUpdate()
          Gets the thisUpdate date from the CRL.
abstract  int getVersion()
          Gets the version (version number) value from the CRL.
 int hashCode()
          Returns a hashcode value for this CRL from its encoded form.
abstract  void verify(PublicKey key)
          Verifies that this CRL was signed using the private key that corresponds to the given public key.
abstract  void verify(PublicKey key, String sigProvider)
          Verifies that this CRL was signed using the private key that corresponds to the given public key.
 
Methods inherited from class java.security.cert.CRL
getType, isRevoked, toString
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 

Constructor Detail

X509CRL

protected X509CRL()
Constructor for X.509 CRLs.
Method Detail

equals

public boolean equals(Object other)
Compares this CRL for equality with the given object. If the other object is an instanceof X509CRL, then its encoded form is retrieved and compared with the encoded form of this CRL.
Overrides:
equals in class Object
Parameters:
other - the object to test for equality with this CRL.
Returns:
true iff the encoded forms of the two CRLs match, false otherwise.

hashCode

public int hashCode()
Returns a hashcode value for this CRL from its encoded form.
Overrides:
hashCode in class Object
Returns:
the hashcode value.

getEncoded

public abstract byte[] getEncoded()
                           throws CRLException
Returns the ASN.1 DER-encoded form of this CRL.
Throws:
CRLException - if an encoding error occurs.

verify

public abstract void verify(PublicKey key)
                     throws CRLException,
                            NoSuchAlgorithmException,
                            InvalidKeyException,
                            NoSuchProviderException,
                            SignatureException
Verifies that this CRL was signed using the private key that corresponds to the given public key.
Parameters:
key - the PublicKey used to carry out the verification.
Throws:
NoSuchAlgorithmException - on unsupported signature algorithms.
InvalidKeyException - on incorrect key.
NoSuchProviderException - if there's no default provider.
SignatureException - on signature errors.
CRLException - on encoding errors.

verify

public abstract void verify(PublicKey key,
                            String sigProvider)
                     throws CRLException,
                            NoSuchAlgorithmException,
                            InvalidKeyException,
                            NoSuchProviderException,
                            SignatureException
Verifies that this CRL was signed using the private key that corresponds to the given public key. This method uses the signature verification engine supplied by the given provider.
Parameters:
key - the PublicKey used to carry out the verification.
sigProvider - the name of the signature provider.
Throws:
NoSuchAlgorithmException - on unsupported signature algorithms.
InvalidKeyException - on incorrect key.
NoSuchProviderException - on incorrect provider.
SignatureException - on signature errors.
CRLException - on encoding errors.

getVersion

public abstract int getVersion()
Gets the version (version number) value from the CRL. The ASN.1 definition for this is: 
 version    Version OPTIONAL,
             -- if present, must be v2

 Version  ::=  INTEGER  {  v1(0), v2(1), v3(2)  }
             -- v3 does not apply to CRLs but appears for consistency
             -- with definition of Version for certs
Returns:
the version number, i.e. 1 or 2.

getIssuerDN

public abstract Principal getIssuerDN()
Gets the issuer (issuer distinguished name) value from the CRL. The issuer name identifies the entity that signed (and issued) the CRL.

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.

getThisUpdate

public abstract Date getThisUpdate()
Gets the thisUpdate date from the CRL. The ASN.1 definition for this is: 
 thisUpdate   ChoiceOfTime
 ChoiceOfTime ::= CHOICE {
     utcTime        UTCTime,
     generalTime    GeneralizedTime }
Returns:
the thisUpdate date from the CRL.

getNextUpdate

public abstract Date getNextUpdate()
Gets the nextUpdate date from the CRL.
Returns:
the nextUpdate date from the CRL, or null if not present.

getRevokedCertificate

public abstract X509CRLEntry getRevokedCertificate(BigInteger serialNumber)
Gets the CRL entry with the given serialNumber from this CRL.
Returns:
the entry with the given serial number, or null if no such entry exists in this CRL.
See Also:
X509CRLEntry

getRevokedCertificates

public abstract Set getRevokedCertificates()
Gets all the entries from this CRL. This returns a Set of X509CRLEntry objects.
Returns:
all the entries or null if there are none present.
See Also:
X509CRLEntry

getTBSCertList

public abstract byte[] getTBSCertList()
                               throws CRLException
Gets the DER-encoded CRL information, the tbsCertList from this CRL. This can be used to verify the signature independently.
Returns:
the DER-encoded CRL information.
Throws:
CRLException - if an encoding error occurs.

getSignature

public abstract byte[] getSignature()
Gets the signature value (the raw signature bits) from the CRL. The ASN.1 definition for this is: 
 signature     BIT STRING
Returns:
the signature.

getSigAlgName

public abstract String getSigAlgName()
Gets the signature algorithm name for the CRL 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.

getSigAlgOID

public abstract String getSigAlgOID()
Gets the signature algorithm OID string from the CRL. 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()#getSigAlgName for relevant ASN.1 definitions.

Returns:
the signature algorithm OID string.

getSigAlgParams

public abstract byte[] getSigAlgParams()
Gets the DER-encoded signature algorithm parameters from this CRL's signature algorithm. In most cases, the signature algorithm parameters are null; the parameters are usually supplied with the public key. If access to individual parameter values is needed then use AlgorithmParameters and instantiate with the name returned by getSigAlgName()#getSigAlgName.

See getSigAlgName()#getSigAlgName for relevant ASN.1 definitions.

Returns:
the DER-encoded signature algorithm parameters, or null if no parameters are present.
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