Methods, systems and computer programs for verifying permissioning rights to one or more data resources associated with a data processing platform (DPP) are disclosed. An exemplary method comprises receiving an assertion statement (AS) identifying a user, a data resource and an operation performable with respect to the data resource, the operation comprising a read operation or a view operation, and applying the AS to a network database storing an access control list defining, for each of a plurality of data resources associated with the DPP, one or more users having permission to perform one or more operations on the respective data resource, wherein applying the AS is effective to determine validity of the AS in relation to the data resource identified in the AS. If the assertion is false, an error message is generated for output; if the assertion is true, the read operation or the view operation is executed.