Validate signature with pre-calculated digest

Question

Hello to all!
I'm trying to build a system that signs and validates signatures on large files.
To get a signature i used a pre-calculated digest and was easy, but for validating the same signature i can't discover how to give the pre-calculated digest.
I can't use the normal validate because the java api uses the "JavaUtils.getBytesFromStream" method and try to get all the file to memory.
can someone indicate the solution to this (or explain why don't had a solution, if it is the case)?

Answer 1

Hello!
smullan wrote:
I assume you have tried returning an OctetStreamData wrapped around an InputStream? Yes. I let here the code of the URIDereferencer i'm using.
public class ConstrulinkURIDereferencer implements URIDereferencer {
     private String filesPath;
     private URIDereferencer defaultDereferencer = null;
     public ConstrulinkURIDereferencer(String filesPath) {
          this.filesPath = filesPath;
     public void setURIDereferencer(URIDereferencer defaultDereferencer) {
          this.defaultDereferencer = defaultDereferencer;
     @Override
     public Data dereference(URIReference uriReference, XMLCryptoContext context)
               throws URIReferenceException {
          try {
               String filename = uriReference.getURI();
               File f = new File(filesPath+filename);
               if (!f.exists() && defaultDereferencer!=null) {
                    return defaultDereferencer.dereference(uriReference, context);
               } else {
                    return new OctetStreamData(new FileInputStream(filesPath+filename));
          } catch (FileNotFoundException e) {
               throw new URIReferenceException(e);
}I try to get a file, if that fails i send the request for dereference to the deafult URIDereferencer (the one that was there before).
What i got from seeing the code at Koders the problem was that when we call the method JavaUtils.getBytesFromStream (you can see the stacktrace above) it will read all the bytes of the stream. I didn't see if these bytes are used for something else than the digest.
>
It sounds like it could be a bug. I will try coming up with a sample and debug it further. If you are able to, please also post your code here or send it to [email protected].
I'll try monday to send you a executable code.
Thanks