A method for maintaining a consistent blockchain ledger for storing commitments across multiple separate blockchains includes: storing a blockchain comprised of a plurality of blocks, each block including at least a block header and one or more blockchain data values; receiving a base commitment from a first node, where the first node is included in a first blockchain network; generating a first new block including at least a first block header and the received base commitment; storing the first new block in the blockchain; receiving a state commitment from an additional node included in each of at least two additional blockchain networks; generating an additional new block including at least an additional block header and each received state commitment; and storing the additional new block in the blockchain.