eSign Image with Metadata signature Leave feedback

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.

• 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 to the options with the add method, or to its signatures collection with the append or add_range method.
• Call Sign method of Signature class instance and pass MetadataSignOptions to it.

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

from datetime import datetime

from groupdocs.signature import Signature
from groupdocs.signature.options import MetadataSignOptions
from groupdocs.signature.domain import ImageMetadataSignature


def sign_png():
    with Signature("sample.png") as signature:
        options = MetadataSignOptions()

        # Image metadata entries are identified by a number, not a name
        metadata_id = 41996

        # Add several Image Metadata signatures with values of different types
        options.add(ImageMetadataSignature(metadata_id, "Mr.Scherlock Holmes"))  # text
        options.add(ImageMetadataSignature(metadata_id + 1, datetime.now()))      # date and time
        options.add(ImageMetadataSignature(metadata_id + 2, 123456))              # whole number
        options.add(ImageMetadataSignature(metadata_id + 3, 123.456))             # floating-point number

        # Sign the image and save the result
        result = signature.sign("signed.png", options)
        print(f"Signed with {len(result.succeeded)} metadata signature(s):")
        for item in result.succeeded:
            print(f"  {item.id}")


if __name__ == "__main__":
    sign_png()

Binary file (PNG, 77 KB)

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

• GroupDocs.Signature for Python via .NET examples, plugins, and showcase

Along with the full-featured Python library, we provide simple but powerful free online apps.

To sign PDF, Word, Excel, PowerPoint, and other documents you can use the online apps from the GroupDocs.Signature App Product Family.