The digital seal is a mechanism that allows to verify (in parts or as a whole) the authenticity and integrity of non-electronic documents automatically by cryptographic means using optical document readers only. The digital seal is a two-dimensional barcode printed on the document and comprises digitally signed data for checking the authenticity of the document and the integrity of relevant document contents, e.g. text or images.
The storage capacity in monochromatic 2D barcodes is limited. In order to enable digital seals to store additional information (such as facial images, fingerprint templates, other biometric information or additional textual data), BSI TR-03137 Part 2 defines Just Another Barcode (JABCode), a color 2D barcode. By using color information, the storage capacity of the barcode is significantly enhanced compared to a monochromatic barcode with the same physical size.
Note that an independent open-source implementation (GNU Lesser GPL) is externally available at https://github.com/jabcode/jabcode