iaik.x509.extensions.smime

Class SMIMECapabilities

java.lang.Object

iaik.x509.V3Extension

iaik.x509.extensions.smime.SMIMECapabilities

public class SMIMECapabilities
extends V3Extension

This class implements the S/MIMEv3 SMIMECapabilities certificate extension.

S/MIMEv3 (RFC 4262) specifies the SMIMECapabilities extension to may be included in a certificate for announcing the cryptographic S/MIME capabilities of the certificate subject. The SMIMECapabilities extension has the same ASN.1 syntax as the SMIMECapabilities attribute defines by RFC 3851:

 SMIMECapability ::= SEQUENCE {
   capabilityID OBJECT IDENTIFIER,
   parameters ANY DEFINED BY capabilityID OPTIONAL } 
 
 SMIMECapabilities ::= SEQUENCE OF SMIMECapability
 

However, whereas the SMIMECapabilities attribute maybe included in an S/MIME mail, the SMIMECapabilities may be included in a certificate. Any algorithm the certificate subject (or her/his S/MIME agent) is able to handle is announced by an SMIMECapability object identifying the algorithm by its OID. The optional parameters field may provide information that may be required to differentiate between two instances of the same algorithm (for instance key length for RC2). Any SMimeCapability to be announced is collected and included into an SMIMECapabilities extension in preference order.

 SMIMECapability ::= SEQUENCE {
   capabilityID OBJECT IDENTIFIER,
   parameters ANY DEFINED BY capabilityID OPTIONAL } 
 
 SMIMECapabilities ::= SEQUENCE OF SMIMECapability
 

When creating an SMIMECapabilities object the list of capabilities has to be supplied. The following example shows how to create an SMIMECapabilities extension containing capabilities announcing the ability to handle the TripleDES algorithm, and the RC2 algorithm for key lengths of 128, 64 and 40 bits, in this preference order:

 // capabilites
 SMIMECapability[] capabilities = new SMIMECapability[5];
 // 3DES
 capabilities[0] = new SMIMECapability(AlgorithmID.des_EDE3_CBC.getAlgorithm());
 // RC2 128
 capabilities[1] = new SMIMECapability(AlgorithmID.rc2_CBC.getAlgorithm());
 capabilities[1].setParameters(new INTEGER(128));
 // RC2 64
 capabilities[2] = new SMIMECapability(AlgorithmID.rc2_CBC.getAlgorithm());
 capabilities[2].setParameters(new INTEGER(64));
 // DES
 capabilities[3] = new SMIMECapability(AlgorithmID.des_CBC.getAlgorithm());
 // RC2 40
 capabilities[4] = new SMIMECapability(AlgorithmID.rc2_CBC.getAlgorithm());
 capabilities[4].setParameters(new INTEGER(40)); 
 SMIMECapabilities smimeCapabilities = new SMIMECapabilities(capabilities);
 ..
 // add es extension to a certificate
 X509Certificate cert = ...;
 cert.addExtension(smimeCapabilities);
 

To parse an SMIMECapabilities extension from a certificate use method getExtension with the SMIMECapabilities oid. Subsequently parse the SMIMECapabilities extension for the included capabilities:

  // the certificate
  X509Certificate cert = ...;
  ...
  // get SMIMECapabilities extension
  SMIMECapabilities smimeCapabilities = (SMIMECapabilities)cert.getExtension(SMIMECapabilities.oid);
  if (smimeCapabilities != null) {
    // get capabilities
    SMIMECapability capabilities[] = smimeCapabilities.getCapabilities();
    if (capabilities != null) {
      for (int i = 0; i < capabilities.length; i++) {
        ...
      }
    }
  }
  
 

See Also:

SMIMECapability, X509Certificate

Field Summary

Fields

Modifier and Type	Field and Description
static ObjectID	oid The object identifier of this SMIMECapabilities extension.

Fields inherited from class iaik.x509.V3Extension

critical

Constructor Summary

Constructors

Constructor and Description
SMIMECapabilities() Empty default constructor.
SMIMECapabilities(SMIMECapability[] capabilities) Creates an SMIMECapabilities extension for the supplied list of algorithm capabilities to be announced.

Method Summary

Methods

Modifier and Type	Method and Description
SMIMECapability[]	getCapabilities() Returns the capabilites included.
SMIMECapability[]	getCapabilities(ObjectID capabilityID) Returns all capabilities with the same capability ID.
ObjectID	getObjectID() Returns the OID identifying the SMIMECapabilities extension.
int	hashCode() Returns a hashcode for this identity.
void	init(ASN1Object obj) Inits this SMIMECapabilities object with an ASN1Object representing the value of this extension.
ASN1Object	toASN1Object() Returns this SMIMECapabilities as ASN1Object.
java.lang.String	toString() Returns a string representation of this SMIMECapabilities.
java.lang.String	toString(boolean detailed) Returns a string representation of this SMIMECapabilities.

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 SMIMECapabilities extension. The corresponding OID string is "1.2.840.113549.1.9.15".

Constructor Detail

SMIMECapabilities

public SMIMECapabilities()

Empty default constructor. Required for dynamic object creation.

SMIMECapabilities

public SMIMECapabilities(SMIMECapability[] capabilities)

Creates an SMIMECapabilities extension for the supplied list of algorithm capabilities to be announced.

Parameters:

capabilities - the algorithm capabilities to be announced

Method Detail

getCapabilities

public SMIMECapability[] getCapabilities()

Returns the capabilites included.

Returns:

all capabilities included in this SMIMECapabilities extension or null if no capabilities are included

getCapabilities

public SMIMECapability[] getCapabilities(ObjectID capabilityID)

Returns all capabilities with the same capability ID.

This method may be used for getting all included SMIMECapability objects belonging to the same algorithm but possibly having different algorithm parameters.

Parameters:

capabilityID - the OID identifying the algorithm in mind

Returns:

all capabilities having the given capabilityID or null if no capabilities with the requested ID are included

init

public void init(ASN1Object obj)
          throws X509ExtensionException

Inits this SMIMECapabilities object with an ASN1Object representing the value of this extension.

The given ASN1Object represents the SEQUENCE of SMIMECapability elements included in the extension:

 SMIMECapabilities ::= SEQUENCE OF SMIMECapability
 

This method is used by the X509Extensions class when parsing the ASN.1 representation of a certificate for properly initializing an included BasicConstraints 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.

Specified by:

init in class V3Extension

Parameters:

obj - the SMimeCapabilities value as ASN1Object

Throws:

X509ExtensionException - if the extension could not be parsed

toASN1Object

public ASN1Object toASN1Object()
                        throws X509ExtensionException

Returns this SMIMECapabilities as ASN1Object. The returned ASN1Object represents the SEQUENCE of SMIMECapability elements included in this extension:

 SMIMECapabilities ::= SEQUENCE OF SMIMECapability
 

Specified by:

toASN1Object in class V3Extension

Returns:

this SMIMECapabilities as ASN1Object

Throws:

X509ExtensionException - if the extension could not be created

getObjectID

public ObjectID getObjectID()

Returns the OID identifying the SMIMECapabilities extension. The corresponding OID string is "1.2.840.113549.1.9.15".

Specified by:

getObjectID in class V3Extension

Returns:

the OID identifying the SMIMECapabilities extension.

hashCode

public int hashCode()

Returns a hashcode for this identity.

Specified by:

hashCode in class V3Extension

Returns:

a hash code for this identity

toString

public java.lang.String toString()

Returns a string representation of this SMIMECapabilities.

Overrides:

toString in class java.lang.Object

Returns:

this SMIMECapabilities as string

toString

public java.lang.String toString(boolean detailed)

Returns a string representation of this SMIMECapabilities.

Parameters:

detailed - whether to print more detailed information

Returns:

this SMIMECapabilities as string