Abstract

Credit networks represent a way of modeling trust between entities in a network. Nodes in the network print their own currency and trust each other for a certain amount of each other’s currency. This allows the network to serve as a decentralized payment infrastructure—arbitrary payments can be routed through the network by passing IOUs between trusting nodes in their respective currencies—and obviates the need for a common currency. Nodes can repeatedly transact with each other and pay for the transaction using trusted currency. A natural question to ask in this setting is: how long can the network sustain liquidity, i.e. how long can the network support the routing of payments before credit dries up? We answer this question in terms of the long term success probability of transactions for various network topologies and credit values. We show that a number of well-known graph families have the remarkable property that repeated transactions do not result in a loss of liquidity. Further, we show using simulations that the success probability of transactions in Erdös-Rényi and powerlaw networks depends only on average node degree and credit capacity, not on network size. Finally, we compare liquidity in credit networks to that in a centralized payment infrastructure and show that credit networks are not significantly less liquid; thus we do not lose much liquidity in return for their robustness and decentralized properties.

Citations