com.entrust.toolkit.asn1.tsp

Class MessageImprint

java.lang.Object

com.entrust.toolkit.asn1.tsp.MessageImprint

All Implemented Interfaces:

ASN1Type

public class MessageImprint
extends java.lang.Object
implements ASN1Type

This class implements the MessageImprint structure as defined in RFC 3161, the Time-Stamp Protocol (TSP) specification.

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

The length of hashedMessage MUST match the length of hash values produced by hashAlgorithm (e.g., 20 bytes for SHA-1 or 16 bytes for MD5).

The hash algorithm indicated in the hashAlgorithm field SHOULD be a known hash algorithm (one-way and collision resistant). That means that it SHOULD be one-way and collision resistant. The Time Stamp Authority SHOULD check whether or not the given hash algorithm is known to be "sufficient" (based on the current state of knowledge in cryptanalysis and the current state of the art in computational resources, for example). If the TSA does not recognize the hash algorithm or knows that the hash algorithm is weak (a decision left to the discretion of each individual TSA), then the TSA SHOULD refuse to provide the time-stamp token by returning a pkiStatusInfo of 'bad_alg'.

Since:

7.0

See Also:

RFC 3161

Constructor Summary

Constructors

Constructor and Description
MessageImprint(AlgorithmID hashAlgorithm) Creates a new MessageImprint object with the specified hash algorithm and an empty hashed message.
MessageImprint(AlgorithmID hashAlgorithm, byte[] hashedMessage) Creates a new MessageImprint object with the specified components.
MessageImprint(ASN1Object obj) Creates a new MessageImprint object from an ASN1Object.

Method Summary

Modifier and Type	Method and Description
void	calculateHashedMessage(byte[] message) Sets the hash of the message by calculating the hash over the message indicated.
void	calculateHashedMessage(java.io.InputStream message) Sets the hash of the message by calculating the hash over the message indicated.
void	decode(ASN1Object obj) Decodes a MessageImprint object from an ASN1Object.
boolean	equals(java.lang.Object obj) Indicates whether some other object is "equal to" this one.
AlgorithmID	getHashAlgorithm() Returns the hash algorithm that was used to create the hash of the message.
byte[]	getHashedMessage() Returns the hash of the message.
int	hashCode() Returns a hash code value for the object.
ASN1Object	toASN1Object() Encodes this MessageImprint object as an ASN1Object.
java.lang.String	toString() Creates a text representation of the ASN.1 structure of this MessageImprint object.

Methods inherited from class java.lang.Object

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

Constructor Detail

MessageImprint

public MessageImprint(AlgorithmID hashAlgorithm)
               throws java.lang.IllegalArgumentException

Creates a new MessageImprint object with the specified hash algorithm and an empty hashed message.

Parameters:

hashAlgorithm - the hash algorithm that was used to create the hash of the message

Throws:

java.lang.IllegalArgumentException - thrown if the parameter is null

MessageImprint

public MessageImprint(AlgorithmID hashAlgorithm,
                      byte[] hashedMessage)
               throws java.lang.IllegalArgumentException

Creates a new MessageImprint object with the specified components.

Parameters:

hashAlgorithm - the hash algorithm that was used to create the hash of the message

hashedMessage - the hash of the message

Throws:

java.lang.IllegalArgumentException - thrown if any of the parameters are null

MessageImprint

public MessageImprint(ASN1Object obj)
               throws CodingException,
                      java.lang.IllegalArgumentException

Creates a new MessageImprint object from an ASN1Object.

The ASN1Object must be a MessageImprint structure.

Parameters:

obj - the ASN.1 representation of a MessageImprint structure

Throws:

CodingException - thrown if an errors occurs while decoding the ANS1Object

java.lang.IllegalArgumentException - thrown if the parameter is null

Method Detail

getHashAlgorithm

public AlgorithmID getHashAlgorithm()

Returns the hash algorithm that was used to create the hash of the message.

Returns:

the hashAlgorithm component

getHashedMessage

public byte[] getHashedMessage()

Returns the hash of the message.

Returns:

the hashedMessage component

calculateHashedMessage

public void calculateHashedMessage(byte[] message)
                            throws java.lang.SecurityException,
                                   java.lang.IllegalArgumentException

Sets the hash of the message by calculating the hash over the message indicated.

Parameters:

message - the message to be hashed

Throws:

java.lang.SecurityException - thrown if the hash algorithm is not implemented by any of the installed JCA providers

java.lang.IllegalArgumentException - thrown if the parameter is null

calculateHashedMessage

public void calculateHashedMessage(java.io.InputStream message)
                            throws java.io.IOException,
                                   java.lang.SecurityException,
                                   java.lang.IllegalArgumentException

Sets the hash of the message by calculating the hash over the message indicated.

Parameters:

message - contains the message to be hashed

Throws:

java.io.IOException - thrown if an error occurred while reading the message from the input stream

java.lang.SecurityException - thrown if the hash algorithm is not implemented by any of the installed JCA providers

java.lang.IllegalArgumentException - thrown if the parameter is null

decode

public void decode(ASN1Object obj)
            throws CodingException,
                   java.lang.IllegalArgumentException

Decodes a MessageImprint object from an ASN1Object.

The ASN1Object must contain a MessageImprint structure.

Specified by:

decode in interface ASN1Type

Parameters:

obj - an ASN.1 representation of a MessageImprint structure

Throws:

CodingException - thrown if an errors occurs while decoding the ANS1Object

java.lang.IllegalArgumentException - thrown if the parameter is null

toASN1Object

public ASN1Object toASN1Object()

Encodes this MessageImprint object as an ASN1Object.

Specified by:

toASN1Object in interface ASN1Type

Returns:

an ASN.1 representation of the MessageImprint structure

toString

public java.lang.String toString()

Creates a text representation of the ASN.1 structure of this MessageImprint object.

Overrides:

toString in class java.lang.Object

Returns:

a text representation of the ASN.1 structure of this object

equals

public boolean equals(java.lang.Object obj)

Indicates whether some other object is "equal to" this one.

Two MessageImprint objects are equal only if their components are equal.

Overrides:

equals in class java.lang.Object

Parameters:

obj - the reference object with which to compare

Returns:

true if the objects are "equal"; false otherwise

hashCode

public int hashCode()

Returns a hash code value for the object.

Overrides:

hashCode in class java.lang.Object

Returns:

a hash code value for this object