iaik.tsp
Class MessageImprint

java.lang.Object
  iaik.tsp.MessageImprint

public class MessageImprint
extends java.lang.Object

This class implements the TSP ASN.1 type MessageImprint as it is specified in RFC 3161.

 MessageImprint ::= SEQUENCE {
     hashAlgorithm    AlgorithmIdentifier,
     hashedMessage    OCTET STRING
 }
 

This class handles the ASN.1 structure and the DER encoding and decoding of this structure.

Constructor Summary

MessageImprint(AlgorithmID hash_algorithm, byte[] hashed_message)
To construct a new MessageImprint object, an AlgorithmID object and the corresponding hash code must be provided.

MessageImprint(ASN1Object component)
This constructor tries to reconstruct a MessageImprint object from a given ASN.1 structure.

Method Summary

static byte[]	calculateHash(byte[] toBeHashed, AlgorithmID hashAlgorithm) This method calculates the hash value of the given data.
boolean	equals(java.lang.Object obj) Compare two MessageImprint objects.
byte[]	getEncoded() This method DER encodes the ASN.1 MessageImprint object.
AlgorithmID	getHashAlgorithm() This method returns the AlgorithmID object.
byte[]	getHashedMessage() This method returns the hashed message.
int	hashCode() Returns a hash code of this MessageImprint.
void	setHashAlgorithm(AlgorithmID hash_algorithm) Sets the hash algorithm to be used.
void	setHashedMessage(byte[] hashed_message) Sets the hashed message.
ASN1Object	toASN1Object() Returns the ASN.1 structure of the MessageImprint object.
java.lang.String	toString() This method returns a string representation of this object.

Methods inherited from class java.lang.Object

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

Constructor Detail

MessageImprint

public MessageImprint(AlgorithmID hash_algorithm,
                      byte[] hashed_message)
               throws java.lang.NullPointerException

To construct a new MessageImprint object, an AlgorithmID object and the corresponding hash code must be provided.

Parameters:

hash_algorithm - A one-way collision resistant hash algorithm.

hashed_message - The hashed message.

Throws:

java.lang.NullPointerException - Thrown if one of the arguments is null.

MessageImprint

public MessageImprint(ASN1Object component)
               throws CodingException

This constructor tries to reconstruct a MessageImprint object from a given ASN.1 structure.

Parameters:

component - ASN.1 structure to reconstruct.

Throws:

CodingException - Thrown if the given ASN1Object is not a MessageImprint ASN.1 object.

Method Detail

getEncoded

public byte[] getEncoded()

This method DER encodes the ASN.1 MessageImprint object.

Returns:

DER encoded MessageImprint object.

toASN1Object

public ASN1Object toASN1Object()

Returns the ASN.1 structure of the MessageImprint object.

Returns:

ASN1Object of the MessageImprint object.

hashCode

public int hashCode()

Returns a hash code of this MessageImprint.

Overrides:

hashCode in class java.lang.Object

Returns:

the hash code

equals

public boolean equals(java.lang.Object obj)

Compare two MessageImprint objects.

Overrides:

equals in class java.lang.Object

Parameters:

obj - Object to compare with.

Returns:

True if x==y otherwise false.

setHashAlgorithm

public void setHashAlgorithm(AlgorithmID hash_algorithm)
                      throws java.lang.NullPointerException

Sets the hash algorithm to be used.

Parameters:

hash_algorithm - The used hash algorithm.

Throws:

java.lang.NullPointerException - If the given parameter is null.

getHashAlgorithm

public AlgorithmID getHashAlgorithm()

This method returns the AlgorithmID object.

Returns:

The stored AlgorithmID object or null.

setHashedMessage

public void setHashedMessage(byte[] hashed_message)

Sets the hashed message.

Parameters:

hashed_message - The hashed message.

getHashedMessage

public byte[] getHashedMessage()

This method returns the hashed message.

Returns:

the hashed message.

toString

public java.lang.String toString()

This method returns a string representation of this object.

Overrides:

toString in class java.lang.Object

Returns:

a string representing the MessageImprint object.

calculateHash

public static byte[] calculateHash(byte[] toBeHashed,
                                   AlgorithmID hashAlgorithm)
                            throws java.security.NoSuchAlgorithmException,
                                   java.lang.NullPointerException

This method calculates the hash value of the given data.

Parameters:

toBeHashed - The data to be hashed.

hashAlgorithm - The used hash algorithm.

Returns:

The hashed data

Throws:

java.security.NoSuchAlgorithmException - Thrown if the given algorithm is not supported.

java.lang.NullPointerException - Thrown if one of the arguments is null.