Under the condition of a discrete logarithm problem, S2 is decrypted by the OPE (Oblivious Polynomial Evaluation) protocol and Lagrange Interpolation Polynomial (scheme 2).

• 在离散对数困难问题的条件下，利用不经意多项式估值协议和拉格朗日插值多项式来解密S2（方案2）。