iaik.ixsil.algorithms

Class SignatureAlgorithm

java.lang.Object

iaik.ixsil.algorithms.Algorithm

iaik.ixsil.algorithms.SignatureAlgorithm

Direct Known Subclasses:

SignatureAlgorithmImplDSA, SignatureAlgorithmImplECDSA, SignatureAlgorithmImplHMAC, SignatureAlgorithmImplRSA

public abstract class SignatureAlgorithm
extends Algorithm

Defines the behaviour of a signature algorithm in addition to the standard algorithm's behaviour. A signature algorithm takes an octet stream as input data. In case of a signature verification it takes a key used for verification and the signature to verify as additional parameters. The result can be obtained with method sign() in case of a signature computation (the octet stream of the signature), or by the verify(java.io.InputStream) method in case of a signature creation (a decision wether or not the specified signature could have been verified).

Field Summary

Fields

Modifier and Type	Field and Description
protected java.io.InputStream	input_ The input data for the algorithm.
protected java.lang.String	jCEProviderName_ The name of the JCE provider to choose for creating signatures.
protected java.security.PrivateKey	privateKey_ The private key used to compute the signature.

Fields inherited from class iaik.ixsil.algorithms.Algorithm

uri_

Constructor Summary

Constructors

Constructor and Description
SignatureAlgorithm()

Method Summary

Modifier and Type	Method and Description
void	setInput(java.io.InputStream input) Sets the octet stream data to be processed by the signature algorithm.
void	setJCEProviderName(java.lang.String providerName) Sets a particular JCE provider to be used for computing the signature.
void	setSignerKey(java.security.PrivateKey signerKey) Sets the private key to be used by the signature algorithm.
abstract void	setVerifierKey(java.security.Key verifierKey) Allows IXSIL to set the key to be used for verifying a signature value.
abstract java.io.InputStream	sign() Computes the signature value for the input previously provided by means of method setInput(java.io.InputStream).
abstract boolean	verifierKeyUnknown() Tells IXSIL if the algorithm knows about the key to use for verifying a signature, or if this key must be set by the IXSIL core.
abstract boolean	verify(java.io.InputStream signature) Verifies the specified signature for the input data previously set with method setInput(java.io.InputStream).

Methods inherited from class iaik.ixsil.algorithms.Algorithm

getURI, setParameters, setURI, toElement

Methods inherited from class java.lang.Object

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

Field Detail

input_

protected java.io.InputStream input_

The input data for the algorithm.

jCEProviderName_

protected java.lang.String jCEProviderName_

The name of the JCE provider to choose for creating signatures.

privateKey_

protected java.security.PrivateKey privateKey_

The private key used to compute the signature.

Constructor Detail

SignatureAlgorithm

public SignatureAlgorithm()

Method Detail

sign

public abstract java.io.InputStream sign()
                                  throws AlgorithmException

Computes the signature value for the input previously provided by means of method setInput(java.io.InputStream). The signature algorithm implementation is responsible to know about the key used to compute the signature value.

Returns:

the signature value for the input specified with method setInput(java.io.InputStream). This value will NOT be base64 encoded.

Throws:

AlgorithmException - if computing the signature fails for any reason.

verify

public abstract boolean verify(java.io.InputStream signature)
                        throws AlgorithmException

Verifies the specified signature for the input data previously set with method setInput(java.io.InputStream). The key necessary to verify the signature can be set either with method setVerifierKey(java.security.Key), or the signature algorithm implementation knows about this key from any other source.

Parameters:

signature - The bytes representing the signature to be verified.

Returns:

true, if the signature is valid, false otherwise.

Throws:

AlgorithmException - if the validity of the signature cannot be checked for any reason.

setVerifierKey

public abstract void setVerifierKey(java.security.Key verifierKey)
                             throws AlgorithmException

Allows IXSIL to set the key to be used for verifying a signature value.

Parameters:

verifierKey - The key to be used for signature verification. Must obviously fit for the implemented algorithm.

Throws:

AlgorithmException - if the key does not fit for the implemented algorithm.

verifierKeyUnknown

public abstract boolean verifierKeyUnknown()

Tells IXSIL if the algorithm knows about the key to use for verifying a signature, or if this key must be set by the IXSIL core.

Returns:

true if the signature algorithm does not know about the verification key.

setInput

public void setInput(java.io.InputStream input)

Sets the octet stream data to be processed by the signature algorithm.

Parameters:

input - The data to be processed by the signature algorithm. Must not be null.

setJCEProviderName

public void setJCEProviderName(java.lang.String providerName)
                        throws AlgorithmException

Sets a particular JCE provider to be used for computing the signature. If this method is never invoked, the most preferred installed provider will be used.

Parameters:

providerName - The name of the JCE provider. A provider with this name must currently be installed. May be null to reset a previously chosen provider.

Throws:

AlgorithmException - if a provider with the specified name is currently not installed.

setSignerKey

public void setSignerKey(java.security.PrivateKey signerKey)
                  throws AlgorithmException

Sets the private key to be used by the signature algorithm.

Parameters:

signerKey - The private key to be used by the signature algorithm.

Throws:

AlgorithmException