Industry is built atop the principle of intellectual property, i.e., knowledge about a system, a process, or something else that can be sold to a customer. Therefore, it is of utmost importance to protect this intellectual property from competitors. For the development of complex systems, companies need to collaborate, each contributing their share of intellectual property needed to develop the system. The exchange of overlapping parts, e.g., interfaces, is needed for the integration and ultimately building the system. Sharing the interface in an incremental way, i.e., by representing it as deltas, i.e., changes made to a model, improves collaboration efficiency. Continuous sharing instead of a version-based sharing can further increase the efficiency. We propose the Deltachain approach, which combines the delta-based representation of models with encryption-based access control, allowing us to use untrusted infrastructure for sharing models.