Methods and systems for the use of multi-party computation (“MPC”) key systems that involve the use of multiple parties, each of which hold respective private data that may be used to evaluate a computation without ever revealing any of the private data held by each party to perform blockchain operations. Using the MPC key systems, the methods and systems generate secure, encrypted communications across distributed computer networks for authorizing use of cryptography-based digital repositories in order to perform blockchain operations in decentralized applications.