- java.lang.Object
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- javax.security.cert.Certificate
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- javax.security.cert.X509Certificate
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public abstract class X509Certificate extends Certificate
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();
ORbyte[] 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 injava.security.cert
.- Since:
- 1.4
- See Also:
Certificate
,X509Extension
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Constructor Summary
Constructors Constructor and Description X509Certificate()
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Method Summary
Methods Modifier and Type Method and Description abstract void
checkValidity()
Checks that the certificate is currently valid.abstract void
checkValidity(Date date)
Checks that the specified date is within the certificate's validity period.static X509Certificate
getInstance(byte[] certData)
Instantiates an X509Certificate object, and initializes it with the specified byte array.static X509Certificate
getInstance(InputStream inStream)
Instantiates an X509Certificate object, and initializes it with the data read from the input streaminStream
.abstract Principal
getIssuerDN()
Gets theissuer
(issuer distinguished name) value from the certificate.abstract Date
getNotAfter()
Gets thenotAfter
date from the validity period of the certificate.abstract Date
getNotBefore()
Gets thenotBefore
date from the validity period of the certificate.abstract BigInteger
getSerialNumber()
Gets theserialNumber
value from the certificate.abstract String
getSigAlgName()
Gets the signature algorithm name for the certificate signature algorithm.abstract String
getSigAlgOID()
Gets the signature algorithm OID string from the certificate.abstract byte[]
getSigAlgParams()
Gets the DER-encoded signature algorithm parameters from this certificate's signature algorithm.abstract Principal
getSubjectDN()
Gets thesubject
(subject distinguished name) value from the certificate.abstract int
getVersion()
Gets theversion
(version number) value from the certificate.-
Methods inherited from class javax.security.cert.Certificate
equals, getEncoded, getPublicKey, hashCode, toString, verify, verify
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Method Detail
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getInstance
public static final X509Certificate getInstance(InputStream inStream) throws CertificateException
Instantiates an X509Certificate object, and initializes it with the data read from the input streaminStream
. The implementation (X509Certificate is an abstract class) is provided by the class specified as the value of thecert.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) ...
- Parameters:
inStream
- an input stream with the data to be read to initialize the certificate.- Returns:
- an X509Certificate object initialized with the data from the input stream.
- Throws:
CertificateException
- if a class initialization or certificate parsing error occurs.
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getInstance
public static final X509Certificate getInstance(byte[] certData) throws CertificateException
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 thecert.provider.x509v1
property in the security properties file.Note: All X509Certificate subclasses must provide a constructor of the form:
public <subClass>(InputStream inStream) ...
- Parameters:
certData
- a byte array containing the DER-encoded certificate.- Returns:
- an X509Certificate object initialized with the data
from
certData
. - Throws:
CertificateException
- if a class initialization or certificate parsing error occurs.
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checkValidity
public abstract void checkValidity() throws CertificateExpiredException, CertificateNotYetValidException
Checks that the certificate is currently valid. It is if the current date and time are within the validity period given in the certificate.The validity period consists of two date/time values: the first and last dates (and times) on which the certificate is valid. It is defined in ASN.1 as:
validity Validity
Validity ::= SEQUENCE { notBefore CertificateValidityDate, notAfter CertificateValidityDate }
CertificateValidityDate ::= CHOICE { utcTime UTCTime, generalTime GeneralizedTime }
- Throws:
CertificateExpiredException
- if the certificate has expired.CertificateNotYetValidException
- if the certificate is not yet valid.
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checkValidity
public abstract void checkValidity(Date date) 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.- Parameters:
date
- the Date to check against to see if this certificate is valid at that date/time.- Throws:
CertificateExpiredException
- if the certificate has expired with respect to thedate
supplied.CertificateNotYetValidException
- if the certificate is not yet valid with respect to thedate
supplied.- See Also:
checkValidity()
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getVersion
public abstract int getVersion()
Gets theversion
(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.
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getSerialNumber
public abstract BigInteger getSerialNumber()
Gets theserialNumber
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.
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getIssuerDN
public abstract Principal getIssuerDN()
Gets theissuer
(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
TheName ::= CHOICE { RDNSequence } RDNSequence ::= SEQUENCE OF RelativeDistinguishedName RelativeDistinguishedName ::= SET OF AttributeValueAssertion AttributeValueAssertion ::= SEQUENCE { AttributeType, AttributeValue } AttributeType ::= OBJECT IDENTIFIER AttributeValue ::= ANY
Name
describes a hierarchical name composed of attributes, such as country name, and corresponding values, such as US. The type of theAttributeValue
component is determined by theAttributeType
; in general it will be adirectoryString
. AdirectoryString
is usually one ofPrintableString
,TeletexString
orUniversalString
.- Returns:
- a Principal whose name is the issuer distinguished name.
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getSubjectDN
public abstract Principal getSubjectDN()
Gets thesubject
(subject distinguished name) value from the certificate. The ASN.1 definition for this is:subject Name
See
getIssuerDN
forName
and other relevant definitions.- Returns:
- a Principal whose name is the subject name.
- See Also:
getIssuerDN()
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getNotBefore
public abstract Date getNotBefore()
Gets thenotBefore
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 }
- Returns:
- the start date of the validity period.
- See Also:
checkValidity()
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getNotAfter
public abstract Date getNotAfter()
Gets thenotAfter
date from the validity period of the certificate. SeegetNotBefore
for relevant ASN.1 definitions.- Returns:
- the end date of the validity period.
- See Also:
checkValidity()
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getSigAlgName
public abstract String getSigAlgName()
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.
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getSigAlgOID
public abstract String getSigAlgOID()
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.
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getSigAlgParams
public abstract byte[] getSigAlgParams()
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.
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