InterceptingSignatureVerification

XAdES4j allows the registration of additional verification logic on different moments of the verification process. All the verifiers presented below can be registered through XadesVerificationProfile.

Early Verifiers

To perform verifications on the signature structure just after unmarshalling, one should use RawSignatureVerifiers:

public interface RawSignatureVerifier
{
  void verify(RawSignatureVerifierContext ctx);
}

These verifiers are invoked after unmarshalling the signature and prior to any actual core or XAdES verification. A possible usage is checking for unsafe transforms on the data object references.

Final Verifiers

If some custom verifications are needed after the built-in verification process, one might use a CustomSignatureVerifier:

public interface CustomSignatureVerifier
{
    public void verify(
            XAdESVerificationResult verificationData,
            QualifyingPropertyVerificationContext ctx);
}

Invoking these verifiers is the last step of the verification process.

Qualifying Property Verifiers

To replace or extend the verification logic for a specific qualifying property, one should implement and register the appropriate QualifyingPropertyVerifier.

public interface QualifyingPropertyVerifier<TData extends PropertyDataObject>
{
    public QualifyingProperty verify(
            TData propData,
            QualifyingPropertyVerificationContext ctx);
}

To access the default verifier for a given qualifying property, custom verifiers should have a constructor dependency and use the BuiltIn annotation. For instance, to extend the verification of the SigningTime property one might do:

class MySigningTimeVerifier implements QualifyingPropertyVerifier<SigningTimeData>
{
    private final QualifyingPropertyVerifier<SigningTimeData> builtInVerifier;

    @Inject
    public MySigningTimeVerifier(
            @BuiltIn QualifyingPropertyVerifier<SigningTimeData> builtInVerifier)
    {
        this.builtInVerifier = builtInVerifier;
    }

    @Override
    public QualifyingProperty verify(SigningTimeData propData, QualifyingPropertyVerificationContext ctx) 
    {
        QualifyingProperty p = builtInVerifier.verify(propData, ctx);
        // Do something else here...
    }
}