public abstract class X509Certificate extends Certificate
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
.
Certificate
,
X509Extension
Constructor and Description |
---|
X509Certificate() |
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 stream
inStream . |
abstract Principal |
getIssuerDN()
Gets the
issuer (issuer distinguished name) value from
the certificate. |
abstract Date |
getNotAfter()
Gets the
notAfter date from the validity period of
the certificate. |
abstract Date |
getNotBefore()
Gets the
notBefore date from the validity period of
the certificate. |
abstract BigInteger |
getSerialNumber()
Gets the
serialNumber 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 the
subject (subject distinguished name) value
from the certificate. |
abstract int |
getVersion()
Gets the
version (version number) value from the
certificate. |
equals, getEncoded, getPublicKey, hashCode, toString, verify, verify
public static final X509Certificate getInstance(InputStream inStream) throws CertificateException
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) ...
inStream
- an input stream with the data to be read to
initialize the certificate.CertificateException
- if a class initialization
or certificate parsing error occurs.public static final X509Certificate getInstance(byte[] certData) throws CertificateException
cert.provider.x509v1
property in the security properties file.
Note: All X509Certificate
subclasses must provide a constructor of the form:
public <subClass>(InputStream inStream) ...
certData
- a byte array containing the DER-encoded
certificate.certData
.CertificateException
- if a class initialization
or certificate parsing error occurs.public abstract void checkValidity() throws CertificateExpiredException, CertificateNotYetValidException
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 ValidityValidity ::= SEQUENCE { notBefore CertificateValidityDate, notAfter CertificateValidityDate }
CertificateValidityDate ::= CHOICE { utcTime UTCTime, generalTime GeneralizedTime }
CertificateExpiredException
- if the certificate has expired.CertificateNotYetValidException
- if the certificate is not
yet valid.public abstract void checkValidity(Date date) throws CertificateExpiredException, CertificateNotYetValidException
date
- the Date to check against to see if this certificate
is valid at that date/time.CertificateExpiredException
- if the certificate has expired
with respect to the date
supplied.CertificateNotYetValidException
- if the certificate is not
yet valid with respect to the date
supplied.checkValidity()
public abstract int getVersion()
version
(version number) value from the
certificate. The ASN.1 definition for this is:
version [0] EXPLICIT Version DEFAULT v1Version ::= INTEGER { v1(0), v2(1), v3(2) }
public abstract BigInteger getSerialNumber()
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 CertificateSerialNumberCertificateSerialNumber ::= INTEGER
public abstract Principal getIssuerDN()
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 NameTheName ::= 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 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
.public abstract Principal getSubjectDN()
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.
getIssuerDN()
public abstract Date getNotBefore()
notBefore
date from the validity period of
the certificate.
The relevant ASN.1 definitions are:
validity ValidityValidity ::= SEQUENCE { notBefore CertificateValidityDate, notAfter CertificateValidityDate }
CertificateValidityDate ::= CHOICE { utcTime UTCTime, generalTime GeneralizedTime }
checkValidity()
public abstract Date getNotAfter()
notAfter
date from the validity period of
the certificate. See getNotBefore
for relevant ASN.1 definitions.checkValidity()
public abstract String getSigAlgName()
signatureAlgorithm AlgorithmIdentifierAlgorithmIdentifier ::= 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.
public abstract String getSigAlgOID()
See getSigAlgName
for
relevant ASN.1 definitions.
public abstract byte[] getSigAlgParams()
See getSigAlgName
for
relevant ASN.1 definitions.
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For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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