Blockchain is receiving an increasing attention from industry and academia as a breakthrough technology that could provide enormous benefits to different sectors. Financial sector is one of those sectors that started to consider applying blockchain. However, it is still in its initial stages. The objective of this paper is to apply blockchain and smart contract technologies in managing investments that implement real Islamic investment policy (profit-loss-sharing agreement), this will result in easier, faster, secure and transparent investment transactions to both investors and entrepreneurs (or businesses). This work proposes a design of middleware infrastructure that implements the real Islamic investment policy (profit-loss-sharing rate) called Musharakah (joint venture), where investors and entrepreneurs share a pre-agreed percentage of profit or loss from the financed project. The platform acts as a trusted third party without the need for another mediator; it will help both investors and entrepreneurs negotiate their terms.