eSign PDF with Metadata signature

GroupDocs.Signature provides PdfMetadataSignature class to specify different Metadata signature objects for MetadataSignOptions instance. 
PDF document metadata is hidden attributes, some of them are visible only over viewing standard document properties like Author, Creation Date, Producer, Entry, Keywords etc.
PDF document metadata contains 3 fields: Name, Value and TagPrefix, combination of Name and Tag prefix should be unique.

PDF document metadata could keep big amount of data that provides ability to keep serialized custom objects with additional encryption in there. See Advanced examples how to embed secure data.

Here are the steps to add metadata signatures into PDF document with GroupDocs.Signature:

How to eSign PDF with Metadata signature

This example shows how to sign PDF document with several e-signatures as metadata.

Signature signature = new Signature("sample.pdf");

// create Metadata option with predefined Metadata text
MetadataSignOptions options = new MetadataSignOptions();

// Create few Pdf Metadata signatures
PdfMetadataSignature[] signatures = new PdfMetadataSignature[]
                new PdfMetadataSignature("Author", "Mr.Scherlock Holmes"),
                new PdfMetadataSignature("DateCreated", new Date()),
                new PdfMetadataSignature("DocumentId", 123456),
                new PdfMetadataSignature("SignatureId", 123.456)//decimal value

// sign document to file
signature.sign("SampleSigned.pdf", options);

How to eSign PDF with standard metadata signatures

This example shows how to sign PDF document with standard standard embedded PDF document metadata signatures. If PDF metadata signature already exists with same name its value will be overwritten.

Signature signature = new Signature("sample.pdf");
// setup options with text of signature
MetadataSignOptions options = new MetadataSignOptions();

// Using standard Pdf Metadata Signatures with new values
MetadataSignature[] signatures = new MetadataSignature[]
                PdfMetadataSignatures.getAuthor().deepClone("Mr.Scherlock Holmes"),
                PdfMetadataSignatures.getCreateDate().deepClone(DateUtils.addDays(new Date(), -1)),
                PdfMetadataSignatures.getMetadataDate().deepClone(DateUtils.addDays(new Date(), -2)),
                PdfMetadataSignatures.getModifyDate().deepClone(DateUtils.addDays(new Date(), -13)),
                PdfMetadataSignatures.getKeywords().deepClone("GroupDocs, Signature, Metadata, Creation Tool"),
                PdfMetadataSignatures.getTitle().deepClone("Metadata Example"),
                PdfMetadataSignatures.getSubject().deepClone("Metadata Test Example"),
                PdfMetadataSignatures.getDescription().deepClone("Metadata Test example description"),

// sign document to file
signature.sign("sample_signed.pdf", options);

More resources

Advanced Usage Topics 

To learn more about document eSign features, please refer to the advanced usage section.

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.