By adopting such IT systems, involved parties can profit from certainty of which contract version is valid, and can review the conditions at any given time. In the following, a blockchain-based multi-party contract management system is introduced, which spans the whole contracting lifecycle. As illustrated in Figure 8, all relevant parties, including the client, prime contractor and all sub-contractors align and agree on the latest conditions to be determined in the contract. The main challenge here is to balance the need for proof, which involves transparency and the need for data privacy.