iaik.x509.extensions
Class IssuerAltName

java.lang.Object
  |
  +--iaik.x509.V3Extension
        |
        +--iaik.x509.extensions.IssuerAltName

public class IssuerAltName

extends V3Extension

This class implements the IssuerAltName extension.

The IssuerAltName extension is a standard X509v3 extension, which has to be marked as being critical if the certificate´s issuer field contains an empty sequence.

Each extension is associated with a specific certificateExtension object identifier, derived from:

 certificateExtension  OBJECT IDENTIFIER ::=
                            {joint-iso-ccitt(2) ds(5) 29}
 id-ce                 OBJECT IDENTIFIER ::=  certificateExtension
 

The object identifier for the IssuerAltName extension is defined as:

id-ce-issuerAltName OBJECT IDENTIFIER ::= { id-ce 18 }

which corresponds to the OID string "2.5.29.18".

The X.509 Certificate and CRL profile presented in the PKIX internet draft draft-ietf-pkix-ipki-part1-07.txt specifies the Issuer Alternative Name extension for associating Internet style identities with the issuer of the certificate. Defined options include an rfc822 name (electronic mail address), a DNS name, an IP address, and an URI:

 IssuerAltName ::= 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}
 

 OtherName ::= SEQUENCE {          
          type-id    OBJECT IDENTIFIER,
          value      [0] EXPLICIT ANY DEFINED BY type-id }
 

 EDIPartyName ::= SEQUENCE {
          nameAssigner            [0]     DirectoryString OPTIONAL,
          partyName               [1]     DirectoryString }
 

 DirectoryString ::= CHOICE {
    teletexString           TeletexString (SIZE (1..maxSize),
    printableString         PrintableString (SIZE (1..maxSize)),
    universalString         UniversalString (SIZE (1..maxSize)),
    bmpString               BMPString (SIZE(1..maxSIZE))
 }
 

If the only issuer identity included in the certificate is an alternative name form (e.g., an electronic mail address), then the issuer distinguished name shall be empty (an empty sequence), and the issuerAltName extension shall be present. If the issuer field contains an empty sequence, the issuerAltName extension shall be marked critical.

More information can be found in the PKIX internet draft draft-ietf-pkix-ipki-part1-07.txt, section 4.2.1.8 "Issuer Alternative Name".

For adding a IssuerAltName extension object to a X509Certificate, use the addExtension method of the X509Certificate class, e.g.:

 X509Certificate cert = new X509Certificate();
  ...
 GeneralNames generalNames = new GeneralNames();
 generalNames.addName(new GeneralName(GeneralName.uniformResourceIdentifier, "http://www.test.com/"));
 IssuerAltName issuerAltName = new IssuerAltName(generalNames);
 cert.addExtension(issuerAltName);
 

When intending to mark this extension as critical (which necessarily has to be done if the certificate´s issuer field is an empty sequence), use the setCritical method of the iaik.x509.V3Extension parent class (note that you have to mark an extension as critical before adding the extension to a certificate):

 issuerAltName.setCritical(true);
 

See Also:

GeneralNames, GeneralName, IA5String, OCTET_STRING, ObjectID, Name, T61String, PrintableString, UNIString, BMPString, V3Extension, X509Extensions, X509Certificate

Field Summary

static ObjectID

oid The object identifier of this IssuerAltName extension.

Fields inherited from class iaik.x509.V3Extension

critical

Constructor Summary

IssuerAltName()
Default Constructor.

IssuerAltName(GeneralNames generalNames)
Constructs an IssuerAltName object form a GeneralNames ASN.1 type.

Method Summary

GeneralNames	getGeneralNames() Returns the alternative name of the issuer.
ObjectID	getObjectID() Returns the object ID of this IssuerAltName extension
int	hashCode() Returns a hashcode for this identity.
void	init(ASN1Object obj) Inits this IssuerAltName implementation with an ASN1object representing the value of this extension.
void	setGeneralNames(GeneralNames alternateName) Sets the alternative name of the issuer.
ASN1Object	toASN1Object() Returns an ASN1Object representing the value of this IssuerAltName extension object.
java.lang.String	toString() Returns a string that represents the of this IssuerAltName extension.

Methods inherited from class iaik.x509.V3Extension

getName, isCritical, setCritical

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

oid

public static final ObjectID oid

The object identifier of this IssuerAltName extension. The corresponding OID string is "2.5.29.18".

Constructor Detail

IssuerAltName

public IssuerAltName()

Default Constructor.

Creates an empty IssuerAltName object. Use setGeneralNames for supplying some GeneralNames object to this IssuerAltName extension.

The critical value per default is set to false. If you want to specify this extension as critical (which necessarily has to be done if the certificate´s issuer field is an empty sequence) before adding it to a certificate, use the setCritical method of the iaik.x509.V3Extension parent class:

 issuerAltName.setCritical(true);
 cert.addExtension(issuerAltName);
 

See Also:

V3Extension.setCritical(boolean)

IssuerAltName

public IssuerAltName(GeneralNames generalNames)

Constructs an IssuerAltName object form a GeneralNames ASN.1 type.

The critical value per default is set to false. If you want to specify this extension as critical (which necessarily has to be done if the certificate´s issuer field is an empty sequence) before adding it to a certificate, use the setCritical method of the iaik.x509.V3Extension parent class:

 X509Certificate cert = new X509Certificate();
  ...
 GeneralNames generalNames = new GeneralNames();
 generalNames.addName(new GeneralName(GeneralName.uniformResourceIdentifier, "http://www.test.com/"));
 IssuerAltName issuerAltName = new IssuerAltName(generalNames);
 issuerAltName.setCritical(true);
 cert.addExtension(issuerAltName); 
 

Parameters:

gn - the alternative name of the issuer as GeneralNames

See Also:

V3Extension.setCritical(boolean), GeneralNames

Method Detail

getObjectID

public ObjectID getObjectID()

Returns the object ID of this IssuerAltName extension

Overrides:

getObjectID in class V3Extension

Returns:

the object ID

init

public void init(ASN1Object obj)
          throws X509ExtensionException

Inits this IssuerAltName implementation with an ASN1object representing the value of this extension.

The given ASN1Object represents a GeneralNames value (additionally) identifying the certificate issuer.

The given ASN1Object is the one created by toASN1Object().

This method is used by the X509Extensions class when parsing the ASN.1 representation of a certificate for properly initializing an included IssuerAltName extension. This method initializes the extension only with its value, but not with its critical specification. For that reason, this method shall not be explicitly called by an application.

Overrides:

init in class V3Extension

Parameters:

obj - the IssuerAltName as ASN1Object

Throws:

X509ExtensionException - if the extension could not be parsed

toASN1Object

public ASN1Object toASN1Object()
                        throws X509ExtensionException

Returns an ASN1Object representing the value of this IssuerAltName extension object.

The returned ASN1Object represents a GeneralNames value (additionally) identifying the certificate issuer.

 IssuerAltName ::= GeneralNames
 

Overrides:

toASN1Object in class V3Extension

Returns:

the value of this IssuerAltName as ASN1Object

Throws:

X509ExtensionException - if the ASN1Object cannot be created because of an coding error

setGeneralNames

public void setGeneralNames(GeneralNames alternateName)

Sets the alternative name of the issuer.

For instance:

 GeneralNames generalNames = new GeneralNames();
 generalNames.addName(new GeneralName(GeneralName.uniformResourceIdentifier, "http://www.test.com/"));
 IssuerAltName issuerAltName = new IssuerAltName();
 issuerAltName.setGeneralNames(generalNames);
 

Parameters:

the - alternative name of the issuer as GeneralNames

See Also:

getGeneralNames(), GeneralNames

getGeneralNames

public GeneralNames getGeneralNames()

Returns the alternative name of the issuer.

Returns:

the alternative name as GeneralNames

See Also:

setGeneralNames(iaik.asn1.structures.GeneralNames), GeneralNames

hashCode

public int hashCode()

Returns a hashcode for this identity.

Overrides:

hashCode in class V3Extension

Returns:

a hash code for this identity

toString

public java.lang.String toString()

Returns a string that represents the of this IssuerAltName extension.

Overrides:

toString in class java.lang.Object

Returns:

the string representation