Sign documents with QR-code embedded object

GroupDocs.Signature provides ability to embed into QR-code signature custom objects. This feature is implemented over object serialization to string and further encryption. By default library uses json format serialization and symmetric encryption, the class SymmetricEncryption class. Creation of this encryption expects 3 arguments like encryption algorithm enumeration SymmetricAlgorithmTypewith one of following values (DES, TripleDES, RC2, Rijndael), string value key and string value salt.

Here are the steps to embed into QR-code text with standard encryption with GroupDocs.Signature: 

  • Implement if needed custom data serialization class that implement IDataSerializer interface. By default GroupDocs.Signature uses embedded json format serialization but allows user to customize it.

  • Implement if needed custom data encryption class that implements IDataEncryption interface. By default GroupDocs.Signature has several encryption implementation you can use but allows user to customize it.

  • Implement class with properties and specify if needed class attributes (like custom serialization attribute, custom encryption attribute), specify attributes for properties like FormatAttribute  to specify serialization name and display format, same as SkipSerializationAttribute to mark property of class as not serialize 

  • Create new instance of  Signature class and pass source document path as a constructor parameter.

  • Create one or several objects of QrCodeSignOptions object with setData value 

  • Instantiate the  QrCodeSignOptions  object according to your requirements and custom object to setData property.

  • Call sign method of  Signature  class instance and pass QrCodeSignOptions to it.

Definition of class

This example shows how to define custom class with serialization and encryption properties and setup Format attributes for properties.

public class DocumentSignatureData
    public String getID(){ return ID; }
    public void setID(String value){ ID = value; }
    @FormatAttribute(propertyName = "SignID")
    public String ID;
    public final String getAuthor(){ return Author; }
    public final void setAuthor(String value){ Author = value; }
    @FormatAttribute(propertyName = "SAuth")
    public String Author;
    //JAVA-added public wrapper for internalized property accessor
    public final java.util.Date getSigned() {  return Signed; }
    public final void setSigned(java.util.Date value) { Signed = value; }
    @FormatAttribute (propertyName = "SDate",propertyFormat = "yyyy-MM-dd")
    public java.util.Date Signed = new java.util.Date();
    public final java.math.BigDecimal getDataFactor() { return DataFactor; }
    public final void setDataFactor(java.math.BigDecimal value) { DataFactor = value; }
    @FormatAttribute (propertyName = "SDFact",propertyFormat = "N2")
    public java.math.BigDecimal DataFactor = new java.math.BigDecimal(0.01);

Implementation of embedding custom object into QR-code signature

This example shows how to embed custom object into QR-code signature.

Signature signature = new Signature("sample.pdf");
// setup key and passphrase
String key = "1234567890";
String salt = "1234567890";
// create data encryption
IDataEncryption encryption = new SymmetricEncryption(SymmetricAlgorithmType.Rijndael, key, salt);
// create custom object
// create custom object
DocumentSignatureData documentSignature = new DocumentSignatureData();
documentSignature.setSigned(new java.util.Date());
documentSignature.setDataFactor(new java.math.BigDecimal("11.22"));
// setup QR-Code options
QrCodeSignOptions options = new QrCodeSignOptions();
// set custom object to serialize to QR Code
// QR-code type
// specify serialization encryption
// locate and aligh signature
Padding padding = new Padding() ;
// sign document to file
SignResult signResult = signature.sign("QrCodeEncryptedObject.pdf", options);
// analyzing result
System.out.print("List of newly created signatures:");
int number = 1;
for(BaseSignature temp : signResult.getSucceeded())
    System.out.print("Signature #"+ number++ +": Type: "+temp.getSignatureType()+" Id:"+temp.getSignatureId()+
            ",Location: "+temp.getLeft()+"x"+temp.getTop()+". Size: "+temp.getWidth()+"x"+temp.getHeight());

More resources

GitHub Examples 

You may easily run the code above and see the feature in action in our GitHub examples:

Free Online App 

Along with full-featured .NET library we provide simple, but powerful free Apps.
You are welcome to eSign PDF, Word, Excel, PowerPoint documents with free to use online GroupDocs Signature App.