java.security.cert.Certificate
java.security.cert.X509Certificate
is new.
java.lang.Object
Abstract class for X.509 certificates. This provides a standard way to access all the attributes of an X.509 certificate.
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:
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.
More information can be found in RFC 2459, "Internet X.509 Public Key Infrastructure Certificate and CRL Profile" at http://www.ietf.org/rfc/rfc2459.txt .
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,
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
}
Certificates are instantiated using a certificate factory. The following is an example of how to instantiate an X.509 certificate:
InputStream inStream = new FileInputStream("fileName-of-cert");
CertificateFactory cf = CertificateFactory.getInstance("X.509");
X509Certificate cert = (X509Certificate)cf.generateCertificate(inStream);
inStream.close();
| Nested Class Summary |
|---|
| Nested classes inherited from class java.security.cert. Certificate |
|---|
| Certificate.CertificateRep |
| Constructor Summary | |
|---|---|
| protected |
X509Certificate
() Constructor for X.509 certificates. |
| Method Summary | |
|---|---|
| abstract void |
checkValidity
() Checks that the certificate is currently valid. |
| abstract void |
checkValidity
(
Date
date) Checks that the given date is within the certificate's validity period. |
| abstract int |
getBasicConstraints
() Gets the certificate constraints path length from the critical BasicConstraints extension, (OID = 2.5.29.19). |
|
List
<
String
|
getExtendedKeyUsage
() Gets an unmodifiable list of Strings representing the OBJECT IDENTIFIERs of the ExtKeyUsageSyntax field of the extended key usage extension, (OID = 2.5.29.37). |
|
Collection
<
List
|
getIssuerAlternativeNames
() Gets an immutable collection of issuer alternative names from the IssuerAltName extension, (OID = 2.5.29.18). |
| abstract Principal |
getIssuerDN
()
Denigrated, replaced by
getIssuerX500Principal()
|
| abstract boolean[] |
getIssuerUniqueID
() Gets the issuerUniqueID value from the certificate. |
| X500Principal |
getIssuerX500Principal
() Returns the issuer (issuer distinguished name) value from the certificate as an X500Principal. |
| abstract boolean[] |
getKeyUsage
() Gets a boolean array representing bits of the KeyUsage extension, (OID = 2.5.29.15). |
| 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 byte[] |
getSignature
() Gets the signature value (the raw signature bits) from the certificate. |
|
Collection
<
List
|
getSubjectAlternativeNames
() Gets an immutable collection of subject alternative names from the SubjectAltName extension, (OID = 2.5.29.17). |
| abstract Principal |
getSubjectDN
()
Denigrated, replaced by
getSubjectX500Principal()
|
| abstract boolean[] |
getSubjectUniqueID
() Gets the subjectUniqueID value from the certificate. |
| X500Principal |
getSubjectX500Principal
() Returns the subject (subject distinguished name) value from the certificate as an X500Principal. |
| abstract byte[] |
getTBSCertificate
() Gets the DER-encoded certificate information, the tbsCertificate from this certificate. |
| abstract int |
getVersion
() Gets the version (version number) value from the certificate. |
| Methods inherited from class java.security.cert. Certificate |
|---|
| equals , getEncoded , getPublicKey , getType , hashCode , toString , verify , verify , writeReplace |
| Methods inherited from class java.lang. Object |
|---|
| clone , finalize , getClass , notify , notifyAll , wait , wait , wait |
| Methods inherited from interface java.security.cert. X509Extension |
|---|
| getCriticalExtensionOIDs , getExtensionValue , getNonCriticalExtensionOIDs , hasUnsupportedCriticalExtension |
| Constructor Detail |
|---|
protected X509Certificate()
| Method Detail |
|---|
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 }
public abstract void checkValidity(Date date)
throws CertificateExpiredException,
CertificateNotYetValidException
public abstract int getVersion()
version [0] EXPLICIT Version DEFAULT v1Version ::= INTEGER { v1(0), v2(1), v3(2) }
public abstract BigInteger getSerialNumber()
serialNumber CertificateSerialNumberCertificateSerialNumber ::= INTEGER
public abstract Principal getIssuerDN()
Denigrated, replaced by
getIssuerX500Principal()
. This method returns the issuer as an implementation specific Principal object, which should not be relied upon by portable code.
Gets the 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 NameThe 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.Name ::= CHOICE { RDNSequence } RDNSequence ::= SEQUENCE OF RelativeDistinguishedName RelativeDistinguishedName ::= SET OF AttributeValueAssertion AttributeValueAssertion ::= SEQUENCE { AttributeType, AttributeValue } AttributeType ::= OBJECT IDENTIFIER AttributeValue ::= ANY
public X500Principal getIssuerX500Principal()
It is recommended that subclasses override this
method.
method to provide an efficient implementation.
public abstract Principal getSubjectDN()
Denigrated, replaced by
getSubjectX500Principal()
. This method returns the subject as an implementation specific Principal object, which should not be relied upon by portable code.
Gets the subject (subject distinguished name) value from the certificate. If the subject value is empty, then the getName() method of the returned Principal object returns an empty string ("").
The ASN.1 definition for this is:
subject Name
See getIssuerDN for Name and other relevant definitions.
public X500Principal getSubjectX500Principal()
It is recommended that subclasses override this
method.
method to provide an efficient implementation.
public abstract Date getNotBefore()
validity ValidityValidity ::= SEQUENCE { notBefore CertificateValidityDate, notAfter CertificateValidityDate }
CertificateValidityDate ::= CHOICE { utcTime UTCTime, generalTime GeneralizedTime }
public abstract Date getNotAfter()
public abstract byte[] getTBSCertificate()
throws CertificateEncodingException
public abstract byte[] getSignature()
signature BIT STRING
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.
public abstract boolean[] getIssuerUniqueID()
The ASN.1 definition for this is:
issuerUniqueID [1] IMPLICIT UniqueIdentifier OPTIONALUniqueIdentifier ::= BIT STRING
public abstract boolean[] getSubjectUniqueID()
The ASN.1 definition for this is:
subjectUniqueID [2] IMPLICIT UniqueIdentifier OPTIONALUniqueIdentifier ::= BIT STRING
public abstract boolean[] getKeyUsage()
KeyUsage ::= BIT STRING {
digitalSignature (0),
nonRepudiation (1),
keyEncipherment (2),
dataEncipherment (3),
keyAgreement (4),
keyCertSign (5),
cRLSign (6),
encipherOnly (7),
decipherOnly (8) }
RFC 2459 recommends that when used, this be marked as a critical extension.
public List
ExtKeyUsageSyntax ::= SEQUENCE SIZE (1..MAX) OF KeyPurposeIdKey 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.KeyPurposeId ::= OBJECT IDENTIFIER
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 abstract and it provides a default implementation. Subclasses should override this method with a correct implementation.
public abstract int getBasicConstraints()
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 pathLenConstraint field (see below) is meaningful only if 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.
Note that for RFC 2459 this extension is always marked critical if cA is TRUE, meaning this certificate belongs to a Certificate Authority.
The ASN.1 definition for this is:
BasicConstraints ::= SEQUENCE {
cA BOOLEAN DEFAULT FALSE,
pathLenConstraint INTEGER (0..MAX) OPTIONAL }
public Collection
The ASN.1 definition of the SubjectAltName extension is:
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}
If this certificate does not contain a SubjectAltName extension, null is returned. Otherwise, a Collection is returned with an entry representing each GeneralName included in the extension. Each entry is a List whose first entry is an Integer (the name type, 0-8) and whose second entry is a String or a byte array (the name, in string or ASN.1 DER encoded form, respectively).
RFC 822, DNS, and URI names are returned as Strings, using the well-established string formats for those types (subject to the restrictions included in RFC 2459). 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 Strings represented as a series of nonnegative integers separated by periods. And directory names (distinguished names) are returned in RFC 2253 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.
Note that the Collection returned may contain more than one name of the same type. Also, note that the returned Collection is immutable and any entries containing byte arrays are cloned to protect against subsequent modifications.
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 abstract and it provides a default implementation. Subclasses should override this method with a correct implementation.
public Collection
The ASN.1 definition of the IssuerAltName extension is:
IssuerAltName ::= GeneralNamesThe ASN.1 definition of GeneralNames is defined in getSubjectAlternativeNames .
If this certificate does not contain an IssuerAltName extension, null is returned. Otherwise, a Collection is returned with an entry representing each GeneralName included in the extension. Each entry is a List whose first entry is an Integer (the name type, 0-8) and whose second entry is a 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 getSubjectAlternativeNames method.
Note that the Collection returned may contain more than one name of the same type. Also, note that the returned Collection is immutable and any entries containing byte arrays are cloned to protect against subsequent modifications.
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 abstract and it provides a default implementation. Subclasses should override this method with a correct implementation.