Privacy Protection of Task in Crowdsourcing: Policy-Hiding and Attribute Updating Attribute-Based Access Control Based on Blockchain

Table 2

Comparisons of blockchain-based access control schemes.

Scheme	Policy privacy	Fine granularity	Attribute update	Policy test	Decentration
[22]
[23]		✓	✓		✓
[26]		✓			✓
[25]
[19]		✓	✓		✓
[18]		✓			✓
[24]		✓			✓
[27]	✓	✓		✓	✓
Our	✓	✓	✓	✓	✓