Hash-linked timestamping is the key feature behind blockchain technology. It makes it possible to design financing contracts that are based on reliable and up-to-date records of transactions. For this reason, it is considered to enhance trust. This paper develops a theoretical model that uses dynamic contract theory to derive optimal financing contracts in a blockchain environment. I show that a dynamically adjusting profit sharing rule is optimal and I highlight properties that determine the splitting rule. In contrast to the view that blockchain enhances traditional contracts like debt and equity by bringing efficiency gains, I emphasise that blockchain allows borrowers to learn from data and take effoort decisions more frequently, which make debt and equity contracts costlier.