Distributed Outsourced Privacy-Preserving Gradient Descent Methods among Multiple Parties

Algorithm 8

Subprotocol prediction.

	Initialization: DO’s encrypted query feature vector , the corresponding key pair (, ), MO’s encrypted coefficient vector , and the corresponding key pair (, ), where and
	Target: prediction result
	Step 1: DO and MO send and to the CS, respectively.
	Step 2: CS computes pr, whereas
	Step 3: CS sends pr to the MO.
	Step 4: MO runs Algorithm 5 and decrypts pr with its key pair (, ) and obtains
	Step 5: MO sends to each DO.
	Step 6: MO runs Algorithm 5 to decrypt with its key pair (, ) and gets access to the desired prediction result: