A method for providing certified confidential data collaboration between untrusted parties, including creating a changeset proposal remotely performing a certified operation and passing the changeset proposal to the certified operation, creating a unique changeset reference validating the changeset proposal and creating a state-at-changeset structure extracting a section-state-at-changeset structure from the changeset proposal, performing a cryptographic hash of the state-at-changeset structure and the section-state-at-changeset structure, writing to a local transactional database a changeset fat twin record communicating a changeset reference notification for each fat twin record to the parties, performing a certified operation in a blockchain a certified thin twin smart contract and passing the changeset reference, the cryptographically hashed state-at-changeset structure and the cryptographically hashed section-state-at-changeset structure, validating that a previous certified operation with the same changeset reference does not exist, writing to the blockchain a new thin twin record and performing a proof-of-certified-operation on the thin twin smart contract.