I want to compute a multiplication between many secret values and then distribute the result to everyone involved. For this, I thought about an MPC protocol built from Threshold Homomorphic Elgamal. All I need is :
- to protect parties secret values
- to compute the product homomorphically and obtain the result encrypted
- only the involved parties should be able to decrypt the obtained product
Is Elgamal secure enough for this context ?
As I have found from the description of the Threshold Elgamal pag. 64 and 66, it assumes an apriori distribution of the secret.