Abstract: In order to solve the problem of key leakage detection of the authenticated encryption algorithm TinyJAMBU, a cube attack model is constructed based on the mixed integer linear programming (MILP) with division property. Moreover, a single key bit leakage detection method based on the reduced round TinyJAMBU is proposed. This method uses inequality equations to describe the division property model of the basic operations in the cryptographic algorithm, and uses the MILP tool to solve and detect the key leakage. The experimental results illustrate that the single key leakage in the reduced TinyJAMBU 345 encryption rounds can still be quickly detected when the cube variables is taken from the 0^th to 63^rd bits of the random number(nonce), where the required time complexity is less than 2⁹ encryption operations and the data complexity is less than 2⁹ chosen plaintext. Compared with the previous methods, this method achieves obvious advantages in both the applicability and the implementation complexity.