iaik.ixsil.algorithms

Class DigestAlgorithmImpl

java.lang.Object

iaik.ixsil.algorithms.Algorithm

iaik.ixsil.algorithms.DigestAlgorithm

iaik.ixsil.algorithms.DigestAlgorithmImpl

public class DigestAlgorithmImpl
extends DigestAlgorithm

Provides an flexible digest algorithm implementation which can be supplied with multiple different types of digest algorithms. If the default constructor is used, the default SHA-1 message digest algorithm will be used, as it has been specified in XML Signature, Message Digests. The Java Cryptography Architecture API is used for implementing the cryptographic computations.

Field Summary

Fields

Modifier and Type	Field and Description
protected java.lang.String	DEFAULT_ALGORITHM_URI_ The default algorithm URI for this algorithm implementation.
protected java.lang.String	JCA_ALGID_ The identifier used for the SHA-1 algorithm within the Java Cryptography Architecture.

Fields inherited from class iaik.ixsil.algorithms.DigestAlgorithm

input_

Fields inherited from class iaik.ixsil.algorithms.Algorithm

uri_

Constructor Summary

Constructors

Constructor and Description
DigestAlgorithmImpl() Standard constructor.
DigestAlgorithmImpl(java.lang.String DigestAlg) Constructor that allows specific digest algorithms to be defined by JCE Algorithm ID.
DigestAlgorithmImpl(java.lang.String URI, java.lang.String DigestAlg) Constructor that allows specific digest algorithms to be defined.

Method Summary

Modifier and Type	Method and Description
java.io.InputStream	digest() Computes the digest for the input data previously specified by means of method DigestAlgorithm.setInput(java.io.InputStream).
java.lang.String	getUriByAlgID(java.lang.String DigestAlg) Returns a digest algorithm URI string based on
org.w3c.dom.Element	toElement(org.w3c.dom.Document signatureDOMDoc) Returns the DOM element representation of the algorithm.

Methods inherited from class iaik.ixsil.algorithms.DigestAlgorithm

setInput

Methods inherited from class iaik.ixsil.algorithms.Algorithm

getURI, setParameters, setURI

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_ALGORITHM_URI_

protected java.lang.String DEFAULT_ALGORITHM_URI_

The default algorithm URI for this algorithm implementation.

JCA_ALGID_

protected java.lang.String JCA_ALGID_

The identifier used for the SHA-1 algorithm within the Java Cryptography Architecture.

Constructor Detail

DigestAlgorithmImpl

public DigestAlgorithmImpl()

Standard constructor. Sets the default value for the algorithm URI to http://www.w3.org/2000/09/xmldsig#sha1.

DigestAlgorithmImpl

public DigestAlgorithmImpl(java.lang.String URI,
                           java.lang.String DigestAlg)

Constructor that allows specific digest algorithms to be defined. The specified URI must be the appropriate type of URI for the Digest Algorithm defined.

For example, the default constructor uses SHA-1

 
 URI:        http://www.w3.org/2000/09/xmldsig#sha1
 JCE AlgID:  SHA-1
 

Note: This constructor does not take any parameters, so only digest algorithms that do not require parameters may be used

Parameters:

URI - The URI to use for the specified digest algorithm

DigestAlg - The JCA/JCE digest algorithm String which identifies the digest algorithm

DigestAlgorithmImpl

public DigestAlgorithmImpl(java.lang.String DigestAlg)

Constructor that allows specific digest algorithms to be defined by JCE Algorithm ID. The URI is determined from a known list based on the JCE .

The following mappings are supported:

 "SHA-1"  , "http://www.w3.org/2000/09/xmldsig#sha1"
 "SHA-224", "http://www.w3.org/2001/04/xmldsig-more#sha224"
 "SHA-256", "http://www.w3.org/2001/04/xmlenc#sha256"
 "SHA-384", "http://www.w3.org/2001/04/xmldsig-more#sha384"
 "SHA-512", "http://www.w3.org/2001/04/xmlenc#sha512"
    

For example, the default constructor uses SHA-1

 
 URI:        http://www.w3.org/2000/09/xmldsig#sha1
 JCE AlgID:  SHA-1
 

Note: This constructor does not take any parameters, so only digest algorithms that do not require parameters may be used

Parameters:

DigestAlg - The JCA/JCE digest algorithm String which identifies the digest algorithm

Method Detail

toElement

public org.w3c.dom.Element toElement(org.w3c.dom.Document signatureDOMDoc)
                              throws AlgorithmException

Returns the DOM element representation of the algorithm.

Specified by:

toElement in class Algorithm

Parameters:

signatureDOMDoc - The DOM document which should be used to create necessary DOM nodes.

Returns:

the DOM element representation of the algorithm.

Throws:

AlgorithmException - if no identifying URI has been specified for this algorithm.

digest

public java.io.InputStream digest()
                           throws AlgorithmException

Computes the digest for the input data previously specified by means of method DigestAlgorithm.setInput(java.io.InputStream).

Specified by:

digest in class DigestAlgorithm

Returns:

the digest bytes for the specified input. This value will NOT be base64 encoded.

Throws:

AlgorithmException - if no input has been specified for the digest algorithm, or if computing the message digest fails for any reason.

getUriByAlgID

public java.lang.String getUriByAlgID(java.lang.String DigestAlg)
                               throws AlgorithmException

Returns a digest algorithm URI string based on

Parameters:

DigestAlg - the digest algorithm ID. For example "SHA-256"

Returns:

a URI that indicates the digest algorithm specified in DigestAlg

Throws:

AlgorithmException - if the algorithm ID is invalid or does not have an associated URI