Abstract: A method of maintaining integrity of a distributed block chain, including blocks of at least a first and second block chain sequence of blocks, the method including: (a) with the blocks of at least a first and second block chain sequence of blocks, reflecting at least the headers of a first block of the first chain in a subsequent first block of the second block chain; (b) reflecting at least the headers of the subsequent first block in a subsequent block of the first chain; (c) for the first chain, and the subsequent block, finding the most recently reflected first block in the reflected subsequent first block block; (d) establishing the most recently reflected first block is known to the most recently reflected second block; and (e) establishing that the second block is known to the current second block and wherein the reflecting includes incorporating the header information of a block of one blockchain into the block of the other blockchain.

Abstract: This disclosure relates to voting systems for collecting votes from multiple voters. The voters are associated with multiple identity public keys that each identify one voter. The system comprises nodes to collect the votes and to combine the votes into a vote container and store the vote container on a public data store. Each node communicates voting public keys between the nodes by using cryptography to remove an association between the voting public keys and the identity public keys to create a list of anonymised voting public keys. Each node, after the association between the voting public keys and the identity public keys is removed, communicates votes, authenticated by the anonymised voting public keys, by using cryptography to remove an association between the votes and the voting public keys to create anonymised votes and combine the anonymised votes into the vote container.