Package com.bfo.box

Class C2PAHelper

java.lang.Object

com.bfo.box.C2PAHelper

public class C2PAHelper
extends Object

A general Helper class for C2PA which functions as a main method, provides utility methods for embedding C2PA in files. See C2PAStore for details on how to use it

See Also:

• C2PAStore

Constructor Summary

Constructors

Constructor	Description
C2PAHelper()

Method Summary

Modifier and Type	Method	Description
static void	main(String[] args)
static Json	readJPEG(InputStream in)	Read a JPEG image from the supplied InputStream and return a Json object describing various aspects of it that are relevant for C2PA.
static List<C2PAStatus>	writeJPEG(Json image, C2PAStore store, OutputStream out)	Save a JPEG, signing and inserting the supplied C2PAStore.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

C2PAHelper

public C2PAHelper()

Method Details

readJPEG

public static Json readJPEG(InputStream in)
                     throws IOException

Read a JPEG image from the supplied InputStream and return a Json object describing various aspects of it that are relevant for C2PA.

• c2pa - if the JPEG image contains a C2PA object, this will be set to a buffer containing the encoded C2PA object
• xmp - if the JPEG image contains an XMP block, this will be set to a buffer containing the XMP data
• data - a buffer which contains the image data after the C2PA and XMP are removed
• insert_offset - an offset into the "data" object that is the suggested location of any new C2PA or XMP data.

Parameters:

in - the InputStream (required)

Returns:

the data as described

Throws:

IOException - if the object failed to load

writeJPEG

public static List<C2PAStatus> writeJPEG(Json image,
 C2PAStore store,
 OutputStream out)
                                  throws IOException

Save a JPEG, signing and inserting the supplied C2PAStore.

• data - a buffer which contains the image data after the C2PA and XMP are removed
• insert_offset - the offset into the "data" object that is the location of any the C2PA and XMP data.
• xmp - (optional) a string or bytebuffer that contains the XMP data to insert. If this value is zero length, or is any other value other than null, a basic XMP will be created and inserted.

After this method exits, the image parameter will be updated to add a c2pa, which is encoded version of the C2PA object that was written.

The C2PA store supplied must have an active manifest with a C2PA_AssertionHashData and that has had C2PASignature.setSigner(java.security.PrivateKey, java.util.List<java.security.cert.X509Certificate>) called on it.

Parameters:

image - the image data, which must have at least data and insert_offset

store - the C2PA store to insert

out - the OutputStream to write to

Returns:

the list of C2PA status codes from signing

Throws:

IOException - if the object failed to save

main

public static void main(String[] args)
                 throws Exception

Throws:

Exception