HA-Med: A Blockchain-Based Solution for Sharing Medical Data with Hidden Policies and Attributes

Table 1

Notations in this paper.

Notation	Description
/	The cyclic multiplicative groups
	Access policy
	User’s attribute set
	The tree-structured access policy
	The symmetric encryption key
	The security parameter
	The public key
	The master secret key
	The ciphertext of medical data
	The ciphertext of the symmetric key
	Information transaction
	Access transaction
	The vector generated by the attribute set
	Attribute hiding vector