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 3280: Internet X.509 Public Key Infrastructure Certificate and CRL Profile.
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:
try (InputStream inStream = new FileInputStream("fileName-of-cert")) { CertificateFactory cf = CertificateFactory.getInstance("X.509"); X509Certificate cert = (X509Certificate)cf.generateCertificate(inStream); }
Protected Constructor Summary
X509Certificate()
Constructor for X.509 certificates.
|
Public Method Summary
abstract void |
checkValidity()
Checks that the certificate is currently valid.
|
abstract void | |
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 {@linkplain #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 {@linkplain #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. |
void |
Inherited Method Summary
Protected Constructors
protected X509Certificate ()
Constructor for X.509 certificates.
Public Methods
public abstract void checkValidity ()
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. |
public abstract void checkValidity (Date date)
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.
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 the date supplied. |
---|---|
CertificateNotYetValidException | if the certificate is not
yet valid with respect to the date supplied. |
See Also
public abstract int getBasicConstraints ()
Gets the certificate constraints path length from the
critical BasicConstraints
extension, (OID = 2.5.29.19).
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.
The ASN.1 definition for this is:
BasicConstraints ::= SEQUENCE { cA BOOLEAN DEFAULT FALSE, pathLenConstraint INTEGER (0..MAX) OPTIONAL }
Returns
- the value of
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 andpathLenConstraint
does not appear,Integer.MAX_VALUE
is returned to indicate that there is no limit to the allowed length of the certification path.
public 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). 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:
ExtKeyUsageSyntax ::= SEQUENCE SIZE (1..MAX) OF KeyPurposeId 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.
Returns
- 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 |
---|
public Collection<List<?>> getIssuerAlternativeNames ()
Gets an immutable collection of issuer alternative names from the
IssuerAltName
extension, (OID = 2.5.29.18).
The ASN.1 definition of the IssuerAltName
extension is:
IssuerAltName ::= GeneralNames
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.
Returns
- an immutable
Collection
of issuer alternative names (ornull
)
Throws
CertificateParsingException | if the extension cannot be decoded |
---|
public abstract Principal getIssuerDN ()
Denigrated, replaced by {@linkplain #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 Name Name ::= 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
.Returns
- a Principal whose name is the issuer distinguished name.
public abstract boolean[] getIssuerUniqueID ()
Gets the 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 3280 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.
The ASN.1 definition for this is:
issuerUniqueID [1] IMPLICIT UniqueIdentifier OPTIONAL UniqueIdentifier ::= BIT STRING
Returns
- the issuer unique identifier or null if it is not present in the certificate.
public X500Principal getIssuerX500Principal ()
Returns the issuer (issuer distinguished name) value from the
certificate as an X500Principal
.
It is recommended that subclasses override this method.
Returns
- an
X500Principal
representing the issuer distinguished name
public abstract boolean[] getKeyUsage ()
Gets a boolean array representing bits of
the 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:
KeyUsage ::= BIT STRING { digitalSignature (0), nonRepudiation (1), keyEncipherment (2), dataEncipherment (3), keyAgreement (4), keyCertSign (5), cRLSign (6), encipherOnly (7), decipherOnly (8) }
Returns
- 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 Date getNotAfter ()
Gets the notAfter
date from the validity period of
the certificate. See getNotBefore
for relevant ASN.1 definitions.
Returns
- the end date of the validity period.
See Also
public abstract Date getNotBefore ()
Gets the notBefore
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
public abstract BigInteger getSerialNumber ()
Gets the 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 CertificateSerialNumber CertificateSerialNumber ::= INTEGER
Returns
- the serial number.
public abstract String getSigAlgName ()
Gets the signature algorithm name for the certificate signature algorithm. An example is the string "SHA256withRSA". 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.
public abstract String getSigAlgOID ()
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 RFC 3279: Algorithms and Identifiers for the Internet X.509 Public Key Infrastructure Certificate and CRL Profile.
See getSigAlgName
for
relevant ASN.1 definitions.
Returns
- the signature algorithm OID string.
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.
If access to individual parameter values is needed then use
AlgorithmParameters
and instantiate with the name returned by
getSigAlgName
.
See getSigAlgName
for
relevant ASN.1 definitions.
Returns
- the DER-encoded signature algorithm parameters, or null if no parameters are present.
public abstract byte[] getSignature ()
Gets the signature
value (the raw signature bits) from
the certificate.
The ASN.1 definition for this is:
signature BIT STRING
Returns
- the signature.
public Collection<List<?>> getSubjectAlternativeNames ()
Gets an immutable collection of subject alternative names from the
SubjectAltName
extension, (OID = 2.5.29.17).
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 String
s,
using the well-established string formats for those types (subject to
the restrictions included in RFC 3280). 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 String
s 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.
Returns
- an immutable
Collection
of subject alternative names (ornull
)
Throws
CertificateParsingException | if the extension cannot be decoded |
---|
public abstract Principal getSubjectDN ()
Denigrated, replaced by {@linkplain #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.
Returns
- a Principal whose name is the subject name.
public abstract boolean[] getSubjectUniqueID ()
Gets the subjectUniqueID
value from the certificate.
The ASN.1 definition for this is:
subjectUniqueID [2] IMPLICIT UniqueIdentifier OPTIONAL UniqueIdentifier ::= BIT STRING
Returns
- the subject unique identifier or null if it is not present in the certificate.
public X500Principal getSubjectX500Principal ()
Returns the subject (subject distinguished name) value from the
certificate as an X500Principal
. If the subject value
is empty, then the getName()
method of the returned
X500Principal
object returns an empty string ("").
It is recommended that subclasses override this method.
Returns
- an
X500Principal
representing the subject distinguished name
public abstract byte[] getTBSCertificate ()
Gets the DER-encoded certificate information, the
tbsCertificate
from this certificate.
This can be used to verify the signature independently.
Returns
- the DER-encoded certificate information.
Throws
CertificateEncodingException | if an encoding error occurs. |
---|
public abstract int getVersion ()
Gets the version
(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, i.e. 1, 2 or 3.
public void verify (PublicKey key, Provider sigProvider)
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 abstract
and it provides a default implementation.
Parameters
key | the PublicKey used to carry out the verification. |
---|---|
sigProvider | the signature provider. |
Throws
NoSuchAlgorithmException | on unsupported signature algorithms. |
---|---|
InvalidKeyException | on incorrect key. |
SignatureException | on signature errors. |
CertificateException | on encoding errors. |
UnsupportedOperationException | if the method is not supported |