For this sort of thing, you could always use git (optionally with signed commits). It’s strictly a generalization of a block chain, since the chain is a tree.

For this sort of thing, you could always use git (optionally with signed commits). It’s strictly a generalization of a block chain, since the chain is a tree. Also, instead of remaining anonymous and trying to scam pension funds, its creator named it after himself. It’s also at least a million times more energy efficient, and has better support for federation (i.e., forks).