Search for encrypted objects Metadata signatures

GroupDocs.Signature provides ability to search for embedded objects in Metadata signatures with standard or custom encryption. Standard encryption is implemented over class SymmetricEncryption class. Creation of this object expects 3 arguments like encryption algorithm enumeration SymmetricAlgorithmType with one of following values (DES, TripleDES, RC2, Rijndael), string value key and string value salt.

Here are the steps to search for embedded Metadata signature with standard encryption with GroupDocs.Signature:

Create new instance of Signature class and pass source document path or stream as a constructor parameter.
Compose object of SymmetricEncryption class with same parameters as secured QR-code was signed with.
Create objects of MetadataSearchOptions class and setup property DataEncryption with object of SymmetricEncryption
Call Search method of Signature class instance and pass MetadataSearchOptions to it.
Call method GetData() of encrypted MetadataSignature object to retrieve object of type Type.

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
{
    [Format("SignID")]
    public string ID { get; set; }
    [Format("SAuth")]
    public string Author { get; set; }
    [Format("SDate", "yyyy-MM-dd")]
    public DateTime Signed { get; set; }
    [Format("SDFact", "N2")]
    public decimal DataFactor { get; set; }
    [SkipSerialization]
    public string Comments { get; set; }
}

Search for embedded object in Metadata signatures

This example shows how to search for embedded objects in Metadata signatures.

using (Signature signature = new Signature("MetadataEncryptedObject.docx"))
{
    // setup key and passphrase
    string key = "1234567890";
    string salt = "1234567890";
    // create data encryption
    IDataEncryption encryption = new SymmetricEncryption(SymmetricAlgorithmType.Rijndael, key, salt);
    MetadataSearchOptions options = new MetadataSearchOptions()
    {
        DataEncryption = encryption
    };
    // search for signatures in document
    List<WordProcessingMetadataSignature> signatures = signature.Search<WordProcessingMetadataSignature>(options);
    Console.WriteLine("\nSource document contains following signatures.");
    // get required metadata signatures
    WordProcessingMetadataSignature mdSignature = signatures.FirstOrDefault(p => p.Name == "Signature");
    if (mdSignature != null)
    {
        DocumentSignatureData documentSignatureData = mdSignature.GetData<DocumentSignatureData>();
        if (documentSignatureData != null)
        {
            Console.WriteLine("Signature has DocumentSignatureData object:\n ID = {0}, Author = {1}, Signed = {2}, DataFactor {3}",
                documentSignatureData.ID, documentSignatureData.Author, documentSignatureData.Signed.ToShortDateString(), documentSignatureData.DataFactor);
        }
    }
    // get required metadata signatures
    WordProcessingMetadataSignature mdAuthor = signatures.FirstOrDefault(p => p.Name == "Author");
    if (mdAuthor != null)
    {
        Console.WriteLine("Metadata signature found. Name : {0}. Value: {1}", mdAuthor.Name, mdAuthor.GetData<string>());
    }
    // get required metadata signatures
    WordProcessingMetadataSignature mdDocId = signatures.FirstOrDefault(p => p.Name == "DocumentId");
    if (mdDocId != null)
    {
        Console.WriteLine("Metadata signature found. Name : {0}. Value: {1}", mdDocId.Name, mdDocId.GetData<string>());
    }
}

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.

Search for embedded object with custom serialization of Metadata signatures Search for encrypted text in Metadata signatures