Social Capital Consensus for Blockchains: Exploring Design Options for Replacement of Proof-of-Stake by Social Influence

Consensus protocols of blockchains usually bind participation to computational power or financial stake. Proof-of-Social-Capital (PoSC) asks whether consensus weight can instead be grounded in social influence. In this paper, we formalize PoSC as a protocol tuple spanning admission and uniqueness, the source and lifecycle of social capital, the mapping from support signals to effective consensus weight, leader election, and non-consensus trust dependencies. This abstraction enables structured analysis of the main security and deployability tradeoffs. For each dimension, we show how concrete design choices alter the threat surface and properties, including Sybil resistance, concentration of consensus power, proposer election, endorsement markets, and privacy. Finally, we provide a brief description of a reference instance with regard to the defined design space.