A Fine-Grained IoT Data Access Control Scheme Combining Attribute-Based Encryption and Blockchain

Table 1

Symbol description.

Symbol	Description
	Data owner
	Data consumer
	File
	Access control policy set by data owner
	Key generated by AES algorithm
	Ciphertext of a file
	The address of the ciphertext of the file on IPFS
	The hash value of the file
	Public key generated by CP-ABE algorithm
	Master key generated by CP-ABE algorithm
	Private key generated by CP-ABE algorithm
	Attribute set of data consumers
	Ciphertext of key
	Decrypted key
	Decrypted file
	Hash value of encrypted file after decryption