1. A method for privacy-preserving sharing of security log data for secure collaboration, comprising: obtaining a first set of log data describing network events associated with one or more network addresses; negotiating, by a computer with a potential partner, to determine a metric for estimating a benefit of sharing data, wherein the potential partner is associated with a second set of log data describing network events associated with one or more network addresses; computing, by the computer, a metric value that preserves the privacy of the first set of log data, based on at least the first set of log data; determining whether the metric value exceeds a predetermined threshold for the determined metric; and responsive to determining that the metric value exceeds the predetermined threshold, negotiating, by the computer with the potential partner, to select a merging process for sharing data with the potential partner; determining a set of rules for sharing data during the merging process; and merging data from the first set of log data with the potential partner according to the set of rules and the negotiated merging process.