A Four-Tier Smart Contract Model with On-Chain Upgrade

Table 1

Subset upgrades of contracts.

Case	Proxy contract	Verification contract	Business contract	Storage contract
1: (P1, T0, L0, D0)	Upgrade	Continue to use	Continue to use	Continue to use
2: (P0, T1, L0, D0)	Continue to use	Upgrade	Continue to use	Continue to use
3: (P0, T0, L1, D0)	Continue to use	Continue to use	Upgrade	Continue to use
4: (P0, T0, L0, D1)	Continue to use	Continue to use	Continue to use	Upgrade