1. A computer-based method, comprising the steps of: receiving an incoming Downloadable; performing a hashing function on the incoming Downloadable to compute an incoming Downloadable ID; retrieving security profile data for the incoming Downloadable from a database of Downloadable security profiles indexed according to Downloadable IDs, based on the incoming Downloadable ID, the security profile data including a list of suspicious computer operations that may be attempted by the Downloadable; appending a representation of the retrieved Downloadable security profile data to the incoming Downloadable, to generate an appended Downloadable; and transmitting the appended Downloadable to a destination computer.