Privacy for cloud computing has become an important issue in recent years. In this paper, the authors propose a threshold-based model for privacy protection in cloud computing with a particular (n +1, t +1) secret sharing scheme which is bases on the matrix and vector. They show how their (n +1, t +1) secret sharing scheme can be applied to protect privacy. They assign each row of the matrix as a key of vector. They make use of the linear correlation and linear independence of the vector to evaluate the rank of the key matrix.