Search for embedded and encrypted objects in QR-code signatures

GroupDocs.Signature provides additional features when searching forQR-code signatures (QrCodeSignature) that were previously encrypted or contains embedded data objects. Summary the abilities are as follow

  • ability to search for embedded custom objects into metadata and decrypt them to original source values
  • ability to search for encrypted text of QR-code signature and decrypt it
  • ability to search for embedded object into QR-code signatures with custom encryption and custom serialization
      

Following topics show different aspects

Alternative implementation of custom data serialization

This example shows how to specify custom serialization class. This class should be implemented as Attribute and IDataSerializer interface.

/**
 * Creates class that implements IDataSerializer interface
 * It cam support common serialization like JSon or custom data format
 */
public class CustomSerializationAttribute implements IDataSerializer{
 
 
    public <T> T deserialize(String source, Class<T> type)
    {
        return new Gson().fromJson(source, type);
    }
    public String serialize(Object data)
    {
        return new Gson().toJson(data);
    }
 
}

Implementation of custom data encryption

This example shows how to specify custom serialization class. This class could be implemented also as Attribute (optional) to specify as class attribute.

public class CustomXOREncryption implements IDataEncryption
{
    /**
     * <p>
     * Gets or sets non empty key for encryption (at least one character)
     * </p>
     */
    public final int getKey(){ return auto_Key; }
    /**
     * <p>
     * Gets or sets non empty key for encryption (at least one character)
     * </p>
     */
    public final void setKey(int value){ auto_Key = value; }
    private int auto_Key;
 
    /**
     * <p>
     * Encode method to encrypt string.
     * </p>
     * @return Returns enccrypted string
     * @param source Source string to encode.
     */
    public final String encode(String source)
    {
        return process(source);
    }
 
    /**
     * <p>
     * Decode method to obtain decrypted string.
     * </p>
     * @return Returns decrypted string
     * @param source Source string to decode.
     */
    public final String decode(String source)
    {
        return process(source);
    }
 
    /**
     * <p>
     * Using XOR operation get encoded / decoded string
     * </p>
     * @return
     * @param source
     */
    private String process(String source)
    {
        StringBuilder src = new StringBuilder(source);
        StringBuilder dst = new StringBuilder(src.length());
        char chTmp;
        for (int index = 0; index < src.length(); ++index)
        {
            chTmp = src.charAt(index);
            chTmp = (char)(chTmp ^ this.getKey());
            dst.append(chTmp);
        }
        return dst.toString();
    }
}

Definition of class

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

public static 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);
}

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.

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