Removing Digital Signatures

To remove a digital signature from a signature field, perform the following tasks:

1. Include project files.

2. Create a Signature client.

3. Get the PDF document that contains a signature to remove.

4. Remove the digital signature from the signature field.

5. Save the PDF document as a PDF file.

Remove a digital signature by using the Signature API (Java):

1. Include project files

   Include client JAR files, such as adobe-signatures-client.jar, in your Java project’s class path.

2. Create a Signature client

   • Create a ServiceClientFactory object that contains connection properties.

   • Create a SignatureServiceClient object by using its constructor and passing the ServiceClientFactory object.

3. Get the PDF document that contains a signature to remove

   • Create a java.io.FileInputStream object that represents the PDF document that contains the signature to remove by using its constructor and passing a string value that specifies the location of the PDF document.

   • Create a com.adobe.idp.Document object by using its constructor and passing the java.io.FileInputStream object.

4. Remove the digital signature from the signature field

   Remove a digital signature from a signature field by invoking the SignatureServiceClient object’s clearSignatureField method and passing the following values:

   • A com.adobe.idp.Document object that represents the PDF document that contains the signature to remove.

   • A string value that specifies the name of the signature field that contains the digital signature.

   The clearSignatureField method returns a com.adobe.idp.Document object that represents the PDF document from which the digital signature was removed.

5. Save the PDF document as a PDF file

   • Create a java.io.File object and ensure that the file extension is .pdf.

   • Invoke the com.adobe.idp.Document object’s copyToFile method. Pass the java.io.File object to copy the contents of the com.adobe.idp.Document object to the file. Ensure that you use the Document object that was returned by the clearSignatureField method.

Remove a digital signature by using the Signature API (web service):

1. Include project files

   Create a Microsoft .NET project that uses MTOM. Ensure that you use the following WSDL definition: http://localhost:8080/soap/services/SignatureService?WSDL&lc_version=9.0.1.

   注意： Replace localhost with the IP address of the server hosting LiveCycle.

2. Create a Signature client

   • Create a SignatureServiceClient object by using its default constructor.

   • Create a SignatureServiceClient.Endpoint.Address object by using the System.ServiceModel.EndpointAddress constructor. Pass a string value that specifies the WSDL to the LiveCycle service (for example, http://localhost:8080/soap/services/SignatureService?WSDL). You do not need to use the lc_version attribute. This attribute is used when you create a service reference.)

   • Create a System.ServiceModel.BasicHttpBinding object by getting the value of the SignatureServiceClient.Endpoint.Binding field. Cast the return value to BasicHttpBinding.

   • Set the System.ServiceModel.BasicHttpBinding object’s MessageEncoding field to WSMessageEncoding.Mtom. This value ensures that MTOM is used.

   • Enable basic HTTP authentication by performing the following tasks:

     • Assign the LiveCycle user name to the field SignatureServiceClient.ClientCredentials.UserName.UserName.

     • Assign the corresponding password value to the field SignatureServiceClient.ClientCredentials.UserName.Password.

     • Assign the constant value HttpClientCredentialType.Basic to the field BasicHttpBindingSecurity.Transport.ClientCredentialType.

     • Assign the constant value BasicHttpSecurityMode.TransportCredentialOnly to the field BasicHttpBindingSecurity.Security.Mode.

3. Get the PDF document that contains a signature to remove

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

   • 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. Pass the byte array, the starting position, and the stream length to read.

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

4. Remove the digital signature from the signature field

   Remove the digital signature by invoking the SignatureServiceClient object’s clearSignatureField 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 to remove.

   The clearSignatureField method returns a BLOB object that represents the PDF document from which the digital signature was removed.

5. Save the PDF document as a PDF file

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

   • Create a byte array that stores the content of the BLOB object that was returned by the sign method. Populate the byte array by getting the value of the BLOB object’s MTOM data member.

   • Create a System.IO.BinaryWriter object by invoking its constructor and passing the System.IO.FileStream object.

   • Write the contents of the byte array to the PDF file by invoking the System.IO.BinaryWriter object’s Write method and passing the byte array.