Package eu.europa.esig.dss.pdf

Class AbstractPDFSignatureService

java.lang.Object

eu.europa.esig.dss.pdf.AbstractPDFSignatureService

All Implemented Interfaces:

PDFSignatureService

Direct Known Subclasses:

ITextPDFSignatureService, PdfBoxSignatureService

public abstract class AbstractPDFSignatureService
extends Object
implements PDFSignatureService

The abstract implementation of a PDF signature service

Field Summary

Fields

Modifier and Type	Field	Description
protected PdfDifferencesFinder	pdfDifferencesFinder	Used to find differences occurred between PDF revisions (e.g. visible changes).
protected PdfMemoryUsageSetting	pdfMemoryUsageSetting	Used to specify load mode of the PDF document
protected PdfObjectModificationsFinder	pdfObjectModificationsFinder	Used to find differences within internal PDF objects occurred between PDF revisions .
protected PdfPermissionsChecker	pdfPermissionsChecker	Used to verify PDF document permissions regarding a new signature creation
protected PdfSignatureFieldPositionChecker	pdfSignatureFieldPositionChecker	Used to verify the signature field position placement validity
protected DSSResourcesHandlerBuilder	resourcesHandlerBuilder	The builder to be used to create a new DSSResourcesHandler for each internal call, defining a way working with internal resources (e.g. in memory or by using temporary files).

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AbstractPDFSignatureService(PDFServiceMode serviceMode, SignatureDrawerFactory signatureDrawerFactory)	Constructor for the PDFSignatureService

Method Summary

Modifier and Type	Method	Description
protected void	addDeveloperExtension(PdfDocumentReader documentReader, String prefix, PdfDict developerExtension)	Adds a new developer extension defined in developerExtension dictionary
DSSDocument	addDssDictionary(DSSDocument document, PdfValidationDataContainer validationDataForInclusion)	This method adds the DSS dictionary (Baseline-LT) to a document without password-protection and without VRI dictionary.
DSSDocument	addDssDictionary(DSSDocument document, PdfValidationDataContainer validationDataForInclusion, char[] pwd)	This method adds the DSS dictionary (Baseline-LT) to a password-protected document without inclusion of VRI dictionary.
DSSDocument	addNewSignatureField(DSSDocument document, SignatureFieldParameters parameters)	This method allows to add a new signature field to an existing pdf document
protected void	analyzePdfModifications(DSSDocument document, PdfCMSRevision pdfRevision, PdfDocumentReader finalRevisionReader, char[] pwd)	This method performs a modification analysis for a single given pdfRevision
void	analyzePdfModifications(DSSDocument document, List<AdvancedSignature> signatures, char[] pwd)	Analyze the PDF revision and try to detect any modification (shadow attacks) for signatures
void	analyzeTimestampPdfModifications(DSSDocument document, List<TimestampToken> timestamps, char[] pwd)	Analyze the PDF revision and try to detect any modification (shadow attacks) for PDf document timestamps
protected void	assertSignatureFieldPositionValid(PdfDocumentReader documentReader, AnnotationBox annotationBox, int pageNumber)	This method verifies validity of the signature field box configuration calling the provided pdfSignatureFieldPositionChecker
protected AnnotationBox	buildSignatureFieldBox(SignatureDrawer signatureDrawer)	Returns a SignatureFieldBox.
protected void	checkPdfPermissions(PdfDocumentReader documentReader, SignatureFieldParameters fieldParameters)	This method verifies the PDF permissions dictionaries
protected abstract DSSMessageDigest	computeDigest(DSSDocument toSignDocument, PAdESCommonParameters parameters)	Computes digest on to be signed data computed on the toSignDocument respectively to the given parameters
protected PdfDict	createDeveloperExtensionDict(PdfDocumentReader documentReader, String baseVersion, Integer extensionLevel, String extensionRevision, String type, String url)	Creates a new developer extension dictionary with the given configuration
protected void	digitalSignatureEnhancement(PdfDocumentReader documentReader, PAdESCommonParameters parameters)	This method ensures the PDF document structure is correct for inclusion of specific digital signature's functionalities
protected void	ensureESICDeveloperExtension1(PdfDocumentReader documentReader)	This method verifies presence of the ESIC developer extension with level 1 in the PDF document.
protected void	ensureESICDeveloperExtension2(PdfDocumentReader documentReader)	This method verifies presence of the ESIC developer extension with level 2 in the PDF document.
protected void	ensureISO_32001DeveloperExtension(PdfDocumentReader documentReader)	This method verifies presence of the ISO 32001 developer extension in the PDF document.
protected void	ensureISO_32002DeveloperExtension(PdfDocumentReader documentReader)	This method verifies presence of the ISO 32002 developer extension in the PDF document.
List<String>	getAvailableSignatureFields(DSSDocument document)	This method returns not signed signature-fields
List<PdfRevision>	getRevisions(DSSDocument document, char[] pwd)	Retrieves revisions from a PDF document
protected String	getType()	Gets the type of the signature dictionary
protected AnnotationBox	getVisibleSignatureFieldBoxPosition(PdfDocumentReader reader, SignatureFieldParameters parameters)	Checks if the signatureFieldBox overlaps with any existing annotations on the given page and returns the respectful signature field box
protected AnnotationBox	getVisibleSignatureFieldBoxPosition(SignatureDrawer signatureDrawer, PdfDocumentReader documentReader, SignatureFieldParameters fieldParameters)	Checks validity of the SignatureField position and returns the calculated signature field box
protected List<PdfModification>	getVisualDifferences(PdfDocumentReader signedRevisionReader, PdfDocumentReader finalRevisionReader)	Returns a list of visual differences between the provided PDF and the signed content
protected DSSResourcesHandler	instantiateResourcesHandler()	This method instantiates a new DSSResourcesFactory
protected boolean	isCAdESDetached(PAdESCommonParameters parameters)	Verifies if the signature is created with a use of "ETSI.CAdES.detached" SubFilter
protected boolean	isDeveloperExtensionPresent(PdfDocumentReader documentReader, String prefix, PdfDict developerExtension)	Verifies whether the specified developer extension is present in the document's catalog.
protected boolean	isDocTimestamp(PdfSignatureDictionary pdfSigDict)	Checks if the given signature dictionary represents a DocTimeStamp
protected boolean	isDocumentTimestampLayer()	Checks if a DocumentTimestamp has to be added in the current mode
protected boolean	isISO_32001(PAdESCommonParameters parameters)	Verifies if the ISO_ profile for 32001 shall be activated
protected boolean	isISO_32002(PAdESCommonParameters parameters)	Verifies if the ISO_ profile for 32002 shall be activated
protected boolean	isSignature(PdfSignatureDictionary pdfSigDict)	Checks if the given signature dictionary represents a Signature
protected abstract PdfDocumentReader	loadPdfDocumentReader(DSSDocument dssDocument, char[] passwordProtection)	Loads PdfDocumentReader instance
protected SignatureDrawer	loadSignatureDrawer(SignatureImageParameters imageParameters)	Returns a SignatureDrawer initialized from a provided signatureDrawerFactory
DSSMessageDigest	messageDigest(DSSDocument toSignDocument, PAdESCommonParameters parameters)	Returns the message-digest computed on PDF signature revision's ByteRange
void	setPdfDifferencesFinder(PdfDifferencesFinder pdfDifferencesFinder)	Sets the PdfDifferencesFinder used to find the differences on pages between given PDF revisions.
void	setPdfMemoryUsageSetting(PdfMemoryUsageSetting pdfMemoryUsageSetting)	Sets the PdfMemoryUsageSetting used to specify the load mode of the PDF document
void	setPdfObjectModificationsFinder(PdfObjectModificationsFinder pdfObjectModificationsFinder)	Sets the PdfObjectModificationsFinder used to find the differences between internal PDF objects occurred between given PDF revisions.
void	setPdfPermissionsChecker(PdfPermissionsChecker pdfPermissionsChecker)	Sets the PdfPermissionsChecker used to verify the PDF document rules for a new signature creation
void	setPdfSignatureFieldPositionChecker(PdfSignatureFieldPositionChecker pdfSignatureFieldPositionChecker)	Sets the PdfSignatureFieldPositionChecker used to verify the validity of new signature field placement.
void	setResourcesHandlerBuilder(DSSResourcesHandlerBuilder resourcesHandlerBuilder)	Sets DSSResourcesFactoryBuilder to be used for a DSSResourcesHandler creation in internal methods.
DSSDocument	sign(DSSDocument toSignDocument, byte[] cmsSignedData, PAdESCommonParameters parameters)	Signs a PDF document
protected abstract DSSDocument	signDocument(DSSDocument toSignDocument, byte[] cmsSignedData, PAdESCommonParameters parameters)	This method creates a signed document from the original toSignDocument, incorporating a new revision, enveloping the provided cmsSignedData
protected AnnotationBox	toPdfPageCoordinates(AnnotationBox fieldAnnotationBox, AnnotationBox pageBox)	This method transforms a fieldAnnotationBox's positions and dimensions according to the given page
protected boolean	validateByteRange(ByteRange byteRange, DSSDocument document, byte[] cms)	This method verifies the validity of /ByteRange field against the extracted from /Contents field cms and the current pdf document

Methods inherited from class java.lang.Object

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

Methods inherited from interface eu.europa.esig.dss.pdf.PDFSignatureService

addDssDictionary, addNewSignatureField, getAvailableSignatureFields, previewPageWithVisualSignature, previewSignatureField

Field Details

resourcesHandlerBuilder

protected DSSResourcesHandlerBuilder resourcesHandlerBuilder

The builder to be used to create a new DSSResourcesHandler for each internal call, defining a way working with internal resources (e.g. in memory or by using temporary files). The resources are used on a document creation Default : eu.europa.esig.dss.signature.resources.InMemoryResourcesHandler, working with data in memory

pdfDifferencesFinder

protected PdfDifferencesFinder pdfDifferencesFinder

Used to find differences occurred between PDF revisions (e.g. visible changes). Default : DefaultPdfDifferencesFinder

pdfObjectModificationsFinder

protected PdfObjectModificationsFinder pdfObjectModificationsFinder

Used to find differences within internal PDF objects occurred between PDF revisions . Default : DefaultPdfModificationsFinder

pdfPermissionsChecker

protected PdfPermissionsChecker pdfPermissionsChecker

Used to verify PDF document permissions regarding a new signature creation

pdfSignatureFieldPositionChecker

protected PdfSignatureFieldPositionChecker pdfSignatureFieldPositionChecker

Used to verify the signature field position placement validity

pdfMemoryUsageSetting

protected PdfMemoryUsageSetting pdfMemoryUsageSetting

Used to specify load mode of the PDF document

Constructor Details

AbstractPDFSignatureService

protected AbstractPDFSignatureService(PDFServiceMode serviceMode,
 SignatureDrawerFactory signatureDrawerFactory)

Constructor for the PDFSignatureService

Parameters:

serviceMode - current instance is used to generate Signature or DocumentTimeStamp revision

signatureDrawerFactory - the factory of SignatureDrawer

Method Details

setResourcesHandlerBuilder

public void setResourcesHandlerBuilder(DSSResourcesHandlerBuilder resourcesHandlerBuilder)

Description copied from interface: PDFSignatureService

Sets DSSResourcesFactoryBuilder to be used for a DSSResourcesHandler creation in internal methods. DSSResourcesHandler defines a way to operate with OutputStreams and create DSSDocuments. Default : eu.europa.esig.dss.signature.resources.InMemoryResourcesHandler. Works with data in memory.

Specified by:

setResourcesHandlerBuilder in interface PDFSignatureService

Parameters:

resourcesHandlerBuilder - DSSResourcesHandlerBuilder

setPdfDifferencesFinder

public void setPdfDifferencesFinder(PdfDifferencesFinder pdfDifferencesFinder)

Description copied from interface: PDFSignatureService

Sets the PdfDifferencesFinder used to find the differences on pages between given PDF revisions. Default : eu.europa.esig.dss.pdf.modifications.DefaultPdfDifferencesFinder

Specified by:

setPdfDifferencesFinder in interface PDFSignatureService

Parameters:

pdfDifferencesFinder - PdfDifferencesFinder

setPdfObjectModificationsFinder

public void setPdfObjectModificationsFinder(PdfObjectModificationsFinder pdfObjectModificationsFinder)

Description copied from interface: PDFSignatureService

Sets the PdfObjectModificationsFinder used to find the differences between internal PDF objects occurred between given PDF revisions. Default : eu.europa.esig.dss.pdf.modifications.DefaultPdfObjectModificationsFinder

Specified by:

setPdfObjectModificationsFinder in interface PDFSignatureService

Parameters:

pdfObjectModificationsFinder - PdfObjectModificationsFinder

setPdfPermissionsChecker

public void setPdfPermissionsChecker(PdfPermissionsChecker pdfPermissionsChecker)

Description copied from interface: PDFSignatureService

Sets the PdfPermissionsChecker used to verify the PDF document rules for a new signature creation

Specified by:

setPdfPermissionsChecker in interface PDFSignatureService

Parameters:

pdfPermissionsChecker - PdfPermissionsChecker

setPdfSignatureFieldPositionChecker

public void setPdfSignatureFieldPositionChecker(PdfSignatureFieldPositionChecker pdfSignatureFieldPositionChecker)

Description copied from interface: PDFSignatureService

Sets the PdfSignatureFieldPositionChecker used to verify the validity of new signature field placement. For example to ensure the new signature field lies within PDF page borders and/or it does not overlap with existing signature fields.

Specified by:

setPdfSignatureFieldPositionChecker in interface PDFSignatureService

Parameters:

pdfSignatureFieldPositionChecker - PdfPermissionsChecker

setPdfMemoryUsageSetting

public void setPdfMemoryUsageSetting(PdfMemoryUsageSetting pdfMemoryUsageSetting)

Description copied from interface: PDFSignatureService

Sets the PdfMemoryUsageSetting used to specify the load mode of the PDF document

Specified by:

setPdfMemoryUsageSetting in interface PDFSignatureService

Parameters:

pdfMemoryUsageSetting - PdfMemoryUsageSetting

loadSignatureDrawer

protected SignatureDrawer loadSignatureDrawer(SignatureImageParameters imageParameters)

Returns a SignatureDrawer initialized from a provided signatureDrawerFactory

Parameters:

imageParameters - SignatureImageParameters to use

Returns:

SignatureDrawer

instantiateResourcesHandler

protected DSSResourcesHandler instantiateResourcesHandler()
                                                   throws IOException

This method instantiates a new DSSResourcesFactory

Returns:

DSSResourcesHandler

Throws:

IOException - if an error occurs on DSSResourcesHandler instantiation

messageDigest

public DSSMessageDigest messageDigest(DSSDocument toSignDocument,
 PAdESCommonParameters parameters)

Description copied from interface: PDFSignatureService

Returns the message-digest computed on PDF signature revision's ByteRange

Specified by:

messageDigest in interface PDFSignatureService

Parameters:

toSignDocument - the document to be signed

parameters - the signature/timestamp parameters

Returns:

DSSMessageDigest

computeDigest

protected abstract DSSMessageDigest computeDigest(DSSDocument toSignDocument,
 PAdESCommonParameters parameters)

Computes digest on to be signed data computed on the toSignDocument respectively to the given parameters

Parameters:

toSignDocument - DSSDocument to be signed

parameters - PAdESCommonParameters

Returns:

DSSMessageDigest

sign

public DSSDocument sign(DSSDocument toSignDocument,
 byte[] cmsSignedData,
 PAdESCommonParameters parameters)

Description copied from interface: PDFSignatureService

Signs a PDF document

Specified by:

sign in interface PDFSignatureService

Parameters:

toSignDocument - the pdf document to be signed

cmsSignedData - the encoded CMS Signed data

parameters - the signature/timestamp parameters

Returns:

DSSDocument

signDocument

protected abstract DSSDocument signDocument(DSSDocument toSignDocument,
 byte[] cmsSignedData,
 PAdESCommonParameters parameters)

This method creates a signed document from the original toSignDocument, incorporating a new revision, enveloping the provided cmsSignedData

Parameters:

toSignDocument - DSSDocument to be signed

cmsSignedData - byte array representing the encoded CMS signed data's binaries

parameters - PAdESCommonParameters

Returns:

DSSDocument

isDocumentTimestampLayer

protected boolean isDocumentTimestampLayer()

Checks if a DocumentTimestamp has to be added in the current mode

Returns:

TRUE if it is a DocumentTimestamp layer, FALSE otherwise

getType

protected String getType()

Gets the type of the signature dictionary

Returns:

String

digitalSignatureEnhancement

protected void digitalSignatureEnhancement(PdfDocumentReader documentReader,
 PAdESCommonParameters parameters)

This method ensures the PDF document structure is correct for inclusion of specific digital signature's functionalities

Parameters:

documentReader - PdfDocumentReader to be extended

parameters - PAdESCommonParameters

ensureESICDeveloperExtension1

protected void ensureESICDeveloperExtension1(PdfDocumentReader documentReader)

This method verifies presence of the ESIC developer extension with level 1 in the PDF document. Creates one, when not present.

Parameters:

documentReader - PdfDocumentReader

ensureESICDeveloperExtension2

protected void ensureESICDeveloperExtension2(PdfDocumentReader documentReader)

This method verifies presence of the ESIC developer extension with level 2 in the PDF document. Creates one, when not present.

Parameters:

documentReader - PdfDocumentReader

ensureISO_32001DeveloperExtension

protected void ensureISO_32001DeveloperExtension(PdfDocumentReader documentReader)

This method verifies presence of the ISO 32001 developer extension in the PDF document. Creates one, when not present.

Parameters:

documentReader - PdfDocumentReader

ensureISO_32002DeveloperExtension

protected void ensureISO_32002DeveloperExtension(PdfDocumentReader documentReader)

This method verifies presence of the ISO 32002 developer extension in the PDF document. Creates one, when not present.

Parameters:

documentReader - PdfDocumentReader

createDeveloperExtensionDict

protected PdfDict createDeveloperExtensionDict(PdfDocumentReader documentReader,
 String baseVersion,
 Integer extensionLevel,
 String extensionRevision,
 String type,
 String url)

Creates a new developer extension dictionary with the given configuration

Parameters:

documentReader - PdfDocumentReader

baseVersion - String

extensionLevel - String

extensionRevision - String

type - String

url - String

Returns:

PdfDict

isCAdESDetached

protected boolean isCAdESDetached(PAdESCommonParameters parameters)

Verifies if the signature is created with a use of "ETSI.CAdES.detached" SubFilter

Parameters:

parameters - PAdESCommonParameters

Returns:

TRUE if the "ETSI.CAdES.detached" SubFilter is used, FALSE otherwise

isISO_32001

protected boolean isISO_32001(PAdESCommonParameters parameters)

Verifies if the ISO_ profile for 32001 shall be activated

Parameters:

parameters - PAdESCommonParameters

Returns:

TRUE if the ISO_ developer extension shall be included, FALSE otherwise

isISO_32002

protected boolean isISO_32002(PAdESCommonParameters parameters)

Verifies if the ISO_ profile for 32002 shall be activated

Parameters:

parameters - PAdESCommonParameters

Returns:

TRUE if the ISO_ developer extension shall be included, FALSE otherwise

isDeveloperExtensionPresent

protected boolean isDeveloperExtensionPresent(PdfDocumentReader documentReader,
 String prefix,
 PdfDict developerExtension)

Verifies whether the specified developer extension is present in the document's catalog. The extension shall fully match the defined parameters.

Parameters:

documentReader - PdfDocumentReader

prefix - String

developerExtension - PdfDict

Returns:

TRUE if the extension is present, FALSE otherwise

addDeveloperExtension

protected void addDeveloperExtension(PdfDocumentReader documentReader,
 String prefix,
 PdfDict developerExtension)

Adds a new developer extension defined in developerExtension dictionary

Parameters:

documentReader - PdfDocumentReader

prefix - String

developerExtension - PdfDict

getRevisions

public List<PdfRevision> getRevisions(DSSDocument document,
 char[] pwd)

Description copied from interface: PDFSignatureService

Retrieves revisions from a PDF document

Specified by:

getRevisions in interface PDFSignatureService

Parameters:

document - the document to extract revisions from

pwd - the password protection phrase used to encrypt the PDF document use 'null' value for not an encrypted document

Returns:

list of extracted PdfRevisions

addDssDictionary

public DSSDocument addDssDictionary(DSSDocument document,
 PdfValidationDataContainer validationDataForInclusion)

Description copied from interface: PDFSignatureService

This method adds the DSS dictionary (Baseline-LT) to a document without password-protection and without VRI dictionary.

Specified by:

addDssDictionary in interface PDFSignatureService

Parameters:

document - the document to be extended

validationDataForInclusion - PdfValidationDataContainer

Returns:

the pdf document with the added dss dictionary

addDssDictionary

public DSSDocument addDssDictionary(DSSDocument document,
 PdfValidationDataContainer validationDataForInclusion,
 char[] pwd)

Description copied from interface: PDFSignatureService

This method adds the DSS dictionary (Baseline-LT) to a password-protected document without inclusion of VRI dictionary.

Specified by:

addDssDictionary in interface PDFSignatureService

Parameters:

document - the document to be extended

validationDataForInclusion - PdfValidationDataContainer

pwd - the password protection used to create the encrypted document (optional)

Returns:

the pdf document with the added dss dictionary

getAvailableSignatureFields

public List<String> getAvailableSignatureFields(DSSDocument document)

Description copied from interface: PDFSignatureService

This method returns not signed signature-fields

Specified by:

getAvailableSignatureFields in interface PDFSignatureService

Parameters:

document - the pdf document

Returns:

the list of empty signature fields

addNewSignatureField

public DSSDocument addNewSignatureField(DSSDocument document,
 SignatureFieldParameters parameters)

Description copied from interface: PDFSignatureService

This method allows to add a new signature field to an existing pdf document

Specified by:

addNewSignatureField in interface PDFSignatureService

Parameters:

document - the pdf document

parameters - the parameters with the coordinates,... of the signature field

Returns:

the pdf document with the new added signature field

loadPdfDocumentReader

protected abstract PdfDocumentReader loadPdfDocumentReader(DSSDocument dssDocument,
 char[] passwordProtection)
                                                    throws IOException,
InvalidPasswordException

Loads PdfDocumentReader instance

Parameters:

dssDocument - DSSDocument to read

passwordProtection - the password used to protect the document

Returns:

PdfDocumentReader

Throws:

IOException - in case of loading error

InvalidPasswordException - if the password is not provided or invalid for a protected document

validateByteRange

protected boolean validateByteRange(ByteRange byteRange,
 DSSDocument document,
 byte[] cms)

This method verifies the validity of /ByteRange field against the extracted from /Contents field cms and the current pdf document

Parameters:

byteRange - ByteRange to be validated

document - DSSDocument current PDF document

cms - byte array representing the binaries extracted from /Contents field

Returns:

TRUE if the /ByteRange is valid, FALSE otherwise

isDocTimestamp

protected boolean isDocTimestamp(PdfSignatureDictionary pdfSigDict)

Checks if the given signature dictionary represents a DocTimeStamp

Parameters:

pdfSigDict - PdfSignatureDictionary to check

Returns:

TRUE if the signature dictionary represents a DocTimeStamp, FALSE otherwise

isSignature

protected boolean isSignature(PdfSignatureDictionary pdfSigDict)

Checks if the given signature dictionary represents a Signature

Parameters:

pdfSigDict - PdfSignatureDictionary to check

Returns:

TRUE if the signature dictionary represents a Signature, FALSE otherwise

getVisibleSignatureFieldBoxPosition

protected AnnotationBox getVisibleSignatureFieldBoxPosition(SignatureDrawer signatureDrawer,
 PdfDocumentReader documentReader,
 SignatureFieldParameters fieldParameters)
                                                     throws IOException

Checks validity of the SignatureField position and returns the calculated signature field box

Parameters:

signatureDrawer - SignatureDrawer

documentReader - PdfDocumentReader

fieldParameters - SignatureFieldParameters

Returns:

AnnotationBox

Throws:

IOException - if an exception occurs

buildSignatureFieldBox

protected AnnotationBox buildSignatureFieldBox(SignatureDrawer signatureDrawer)
                                        throws IOException

Returns a SignatureFieldBox. Used for a SignatureField position validation.

Parameters:

signatureDrawer - SignatureDrawer

Returns:

AnnotationBox

Throws:

IOException - if an exception occurs

getVisibleSignatureFieldBoxPosition

protected AnnotationBox getVisibleSignatureFieldBoxPosition(PdfDocumentReader reader,
 SignatureFieldParameters parameters)
                                                     throws IOException

Checks if the signatureFieldBox overlaps with any existing annotations on the given page and returns the respectful signature field box

Parameters:

reader - PdfDocumentReader to be validated

parameters - SignatureFieldParameters

Returns:

AnnotationBox computed signature field box

Throws:

IOException - if an exception occurs

assertSignatureFieldPositionValid

protected void assertSignatureFieldPositionValid(PdfDocumentReader documentReader,
 AnnotationBox annotationBox,
 int pageNumber)

This method verifies validity of the signature field box configuration calling the provided pdfSignatureFieldPositionChecker

Parameters:

documentReader - PdfDocumentReader document where the new signature field should be created

annotationBox - AnnotationBox defining position and dimensions of the new signature field

pageNumber - the number of a page where the new signature should be created

toPdfPageCoordinates

protected AnnotationBox toPdfPageCoordinates(AnnotationBox fieldAnnotationBox,
 AnnotationBox pageBox)

This method transforms a fieldAnnotationBox's positions and dimensions according to the given page

Parameters:

fieldAnnotationBox - AnnotationBox computed field of a signature

pageBox - AnnotationBox page's box

Returns:

AnnotationBox

analyzePdfModifications

public void analyzePdfModifications(DSSDocument document,
 List<AdvancedSignature> signatures,
 char[] pwd)

Description copied from interface: PDFSignatureService

Analyze the PDF revision and try to detect any modification (shadow attacks) for signatures

Specified by:

analyzePdfModifications in interface PDFSignatureService

Parameters:

document - DSSDocument the document

signatures - the different signatures to be analysed

pwd - String password protection

analyzeTimestampPdfModifications

public void analyzeTimestampPdfModifications(DSSDocument document,
 List<TimestampToken> timestamps,
 char[] pwd)

Description copied from interface: PDFSignatureService

Analyze the PDF revision and try to detect any modification (shadow attacks) for PDf document timestamps

Specified by:

analyzeTimestampPdfModifications in interface PDFSignatureService

Parameters:

document - DSSDocument the document

timestamps - the detached document timestamps to be analysed

pwd - String password protection

analyzePdfModifications

protected void analyzePdfModifications(DSSDocument document,
 PdfCMSRevision pdfRevision,
 PdfDocumentReader finalRevisionReader,
 char[] pwd)
                                throws IOException

This method performs a modification analysis for a single given pdfRevision

Parameters:

document - DSSDocument the validating document

pdfRevision - PdfCMSRevision signature revision to be validated

finalRevisionReader - PdfDocumentReader final document revision

pwd - char array representing the password string

Throws:

IOException - if an exception occurs while reading the PDF document

getVisualDifferences

protected List<PdfModification> getVisualDifferences(PdfDocumentReader signedRevisionReader,
 PdfDocumentReader finalRevisionReader)

Returns a list of visual differences between the provided PDF and the signed content

Parameters:

signedRevisionReader - PdfDocumentReader for the signed revision content

finalRevisionReader - PdfDocumentReader for the input PDF document

Returns:

a list of PdfModifications

checkPdfPermissions

protected void checkPdfPermissions(PdfDocumentReader documentReader,
 SignatureFieldParameters fieldParameters)

This method verifies the PDF permissions dictionaries

Parameters:

documentReader - PdfDocumentReader document to be checked

fieldParameters - SignatureFieldParameters identifying a new signature field configuration