eSign Image with Metadata signature

Metadata signature for Image document is an electronic signature based on image metadata standard. Most image formats support metadata specification or EXIF. Image metadata is dictionary map with unique whole short identifier in range 0-65535, Some identifiers are reserved by EXIF specification. From signature perspective image metadata may content any hidden value of standard (int,char, string) or custom type (user defined class), be encrypted and decrypted back by known key over Search method.

GroupDocs.Signature provides ImageMetadataSignature class to specify Metadata e-signature for image documents. Image document metadata contains pair with unique identifier Id and its Value.
Image document metadata could keep big amount of data that provides ability to keep serialized custom objects with additional encryption in there. See more examples here.

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

Create new instance of Signature class and pass source document path as a constructor parameter.
Instantiate the MetadataSignOptions object according to your requirements.
Instantiate one or several ImageMetadataSignature objects and add them into MetadataSignOptions to metadata signatures collection (getSignatures) via add or addRange method.
Call sign method of Signature class instance and pass MetadataSignOptions to it.

How to eSign Image with Metadata signature

This example shows how to sign png image with metadata e-signatures

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

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

// Specify different Metadata Signatures and add them to options signature collection
int imgsMetadataId = 41996;

// Create several Image Metadata signatures with different types
ImageMetadataSignature[] signatures = new ImageMetadataSignature[]
        {
                new ImageMetadataSignature(imgsMetadataId++, 123456), // int
                new ImageMetadataSignature(imgsMetadataId++, "Mr.Scherlock Holmes"), // string
                new ImageMetadataSignature(imgsMetadataId++,new Date()), // date time
                new ImageMetadataSignature(imgsMetadataId++, 123.456), //decimal value
        };
options.getSignatures().addRange(signatures);

// sign document to file
signature.sign("SampleSigned.jpg", 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.

eSign document with Metadata signature eSign PDF with Metadata signature