Blockchain-Based Fine-Grained Data Sharing for Multiple Groups in Internet of Things

Algorithm 1

Signature verification.

	Input:: system public key
	: message
	: the group signature of message
	Output:/: the verification result.
	(1) Compute the following values:
	(2) GM randomly selects computes , then sends to as its member certificate.
	(3) User checks if . If successful, then is its signing key.
	(4) ifthen
	(5)  return
	(6) else
	(7)  return
	(8) end if