de.flexiprovider.pki
Class AlgorithmIdentifier

java.lang.Object
  |
  +--java.util.AbstractCollection
        |
        +--java.util.AbstractList
              |
              +--java.util.ArrayList
                    |
                    +--codec.asn1.ASN1AbstractCollection
                          |
                          +--codec.asn1.ASN1Sequence
                                |
                                +--codec.x509.AlgorithmIdentifier
                                      |
                                      +--de.flexiprovider.pki.AlgorithmIdentifier

All Implemented Interfaces:

codec.asn1.ASN1Collection, codec.asn1.ASN1Type, java.lang.Cloneable, java.util.Collection, java.io.Externalizable, java.util.List, java.io.Serializable

public class AlgorithmIdentifier

extends codec.x509.AlgorithmIdentifier

This class represents the ASN.1/DER value of the AlgorithmIdentifier defined in Annex D to Recommendation X.509. This structure is extensively used for instance in the PKCS standards of RSA Inc. The ASN.1 definition of this structure is as given below:

 AlgorithmIdentifier  ::= SEQUENCE{
   algorithm  OBJECT IDENTIFIER,
   parameters ANY DEFINED BY algorithm OPTIONAL
 }
 

For this class to work properly, providers need to define the following algorithm aliases for the AlgorithmParameters implementations they provide:

1. AlgorithmParameters.MyAlg = class
2. Alg.Alias.AlgorithmParameters.1.2.3.4 = MyAlg
3. Alg.Alias.AlgorithmParameters.OID.1.2.3.4 = MyAlg

The first property defined the mapping of the JCE compliant standard name of the algorithm to the implementing class. The second provider entry allows mapping OID to those algorithm names while the third allows mapping those names on corresponding OID.

The alias definitions are used by this class in order to find an AlgorithmParameters implementation for the OID embedded in the X.509 AlgorithmIdentifier structure, and to create the OID for a given AlgorithmParameters instances. This is done by means of the JCA class, which operates on the engine and alias definitions of the installed providers.

Author:

Volker Roth

See Also:

codec.util.JCA, Serialized Form

Fields inherited from class codec.x509.AlgorithmIdentifier

algorithm_, parameters_

Fields inherited from class java.util.AbstractList

modCount

Constructor Summary

AlgorithmIdentifier()
This method builds the tree of ASN.1 objects used for decoding this structure.

AlgorithmIdentifier(codec.asn1.ASN1ObjectIdentifier oid, codec.asn1.ASN1Type params)
Creates an instance with the given OID and parameters.

AlgorithmIdentifier(codec.asn1.ASN1ObjectIdentifier oid, byte[] b)
Creates an instance with the given OID and opaque algorithm parameter representation.

Method Summary

AlgorithmParameters

getParams() This method locates a suitable AlgorithmParameters implementation if it is available from the JCE compliant security providers that are installed locally.

Methods inherited from class codec.x509.AlgorithmIdentifier

clone, createAlgorithmIdentifier, equals, getAlgorithmName, getAlgorithmOID, getParameters, hashCode, toString

Methods inherited from class codec.asn1.ASN1Sequence

getTag

Methods inherited from class codec.asn1.ASN1AbstractCollection

checkConstraints, decode, encode, getCollection, getConstraint, getTagClass, getValue, isExplicit, isOptional, isType, readExternal, setConstraint, setExplicit, setOptional, writeExternal

Methods inherited from class java.util.ArrayList

add, add, addAll, addAll, clear, contains, ensureCapacity, get, indexOf, isEmpty, lastIndexOf, remove, removeRange, set, size, toArray, toArray, trimToSize

Methods inherited from class java.util.AbstractList

iterator, listIterator, listIterator, subList

Methods inherited from class java.util.AbstractCollection

containsAll, remove, removeAll, retainAll

Methods inherited from class java.lang.Object

, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Collection

add, addAll, clear, contains, containsAll, isEmpty, iterator, remove, removeAll, retainAll, size, toArray, toArray

Methods inherited from interface java.util.List

containsAll, iterator, listIterator, listIterator, remove, removeAll, retainAll, subList

Constructor Detail

AlgorithmIdentifier

public AlgorithmIdentifier()

This method builds the tree of ASN.1 objects used for decoding this structure.

AlgorithmIdentifier

public AlgorithmIdentifier(codec.asn1.ASN1ObjectIdentifier oid,
                           byte[] b)
                    throws codec.asn1.ASN1Exception

Creates an instance with the given OID and opaque algorithm parameter representation. Both the given OID and the parameter encoding is cloned or copied. No side effects occur if these arguments are modified after completion of this constructor.

Parameters:

oid - The algorithm object identifier.

b - The opaque DER encoding of the parameters for the algorithm known under the given OID. If no parameters are required then null might be passed. In that case ASN.1NULL is encoded.

Throws:

codec.asn1.ASN1Exception - if the opaque representation does not contain a valid DER header and contents octets.

AlgorithmIdentifier

public AlgorithmIdentifier(codec.asn1.ASN1ObjectIdentifier oid,
                           codec.asn1.ASN1Type params)
                    throws codec.asn1.ASN1Exception

Creates an instance with the given OID and parameters. The parameters are encoded according to DER and stored by means of an opaque type. If the given parameters are null then an ASN.1 NULL is encoded.

Parameters:

oid - The OID to use.

params - The ASN.1 type of which the parameters consist.

Throws:

codec.asn1.ASN1Exception - if the given parameters cannot be encoded. This should rarely happen.

Method Detail

getParams

public AlgorithmParameters getParams()
                              throws NoSuchAlgorithmException,
                                     InvalidAlgorithmParameterException

This method locates a suitable AlgorithmParameters implementation if it is available from the JCE compliant security providers that are installed locally.

Such providers need to specify the following aliases for this to work:

• AlgorithmParameters.MyAlg = class
• Alg.Alias.AlgorithmParameters.1.2.3.4 = MyAlg

If you ever want to test a provider for compliance with the JCE and cleverness, test it against the FhG-IGD PKCS package. If it doesn't work then better demand fixes from the provider's vendor.

This method may be called only if this instance is initialised properly either by specifying AlgorithmParameters in a constructor or by parsing a valid ASN.1/DER encoding.

Returns:

The AlgorithmParameters or null if none are enclosed in this structure.

Throws:

NoSuchAlgorithmException - if no matching AlgorithmParameters engine is found.

InvalidAlgorithmParameterException - if the parameters cannot be decoded properly.