Verifying digital signatures using the web service API

1.	Include project files

•	Create a Microsoft .NET client assembly that consumes the Signature WSDL. For information, see Creating a .NET client assembly.

•	Reference the Microsoft .NET client assembly. For information, see Referencing the .NET client assembly.

2.	Create a Signature client

Using the Microsoft .NET client assembly, create a SignatureServiceService object by invoking its default constructor.

3.	Get the PDF document that contains the signature to verify

•	Create a BLOB object by using its constructor. The BLOB object is used to store a PDF document that contains a digital or certified signature to verify.

•	Create a System.IO.FileStream object by invoking its constructor and passing a string value that represents the file location of the signed PDF document and the mode in which to open the file.

•	Create a byte array that stores the content of the System.IO.FileStream object. You can determine the size of the byte array by getting the System.IO.FileStream object’s Length property.

•	Populate the byte array with stream data by invoking the System.IO.FileStream object’s Read method and passing the byte array, the starting position, and the stream length to read.

•	Populate the BLOB object by assigning its binaryData property with the contents of the byte array.

4.	Verify the digital signature

Verify the digital signature by invoking the SignatureServiceService object’s verify method and passing the following values:

•	A BLOB object that contains the signed PDF document.

•	A string value that represents the name of the signature field that contains the digital signature. For example, you can specify form1[0].#subform[0].SignatureField1[0]if this field contains a digital signature to verify.

•	A RevocationCheckStyle object that specifies a static data member that represents the revocation checking options. For example, you can specify RevocationCheckStyle.NoCheck that results in revocation checking not being performed.

•	A Boolean value that specifies whether the revocation check style is specified.

•	A VerificationTime object that specifies a static data member that represents a verification time that is used to verify a digital signature. For example, you can specify VerificationTime.CurrentTime that results in the current time being used.

•	A Boolean value that specifies whether the revocation verification time is specified.

•	A OCSPPreferences object that stores preferences for OCSP support. You can specify null for this parameter.

•	A CRLPreferences object that stores CRL related preferences. You can specify null for this parameter.

•	A TSPPreferences object that stores preferences for TSP support. You can specify null for this parameter.

•	A PathValidationPreferences object that controls RFC3280-related path validation options. You can specify null for this parameter.

The verify method returns a PDFSignatureVerificationResult object that contains information that can be used to verify the digital signature.

5.	Determine the signer’s identity

Determine the status of the signer by checking the value of the PDFSignatureVerificationResult object’s signerStatus data member. For example, if the signer is not trusted, the value of this data member is IdentityStatus.Nottrusted.

6.	Determine the status of the signature

Determine the status of the signature by checking the value of the PDFSignatureVerificationResult object’s signatureStatus data member. For example, if the signature is not valid, the value of this data member is PDFSignatureStatus.Invalid.

Current page: http://livedocs.adobe.com/livecycle/es/sdkHelp/programmer/sdkHelp/signaturesVerify.91.4.html