Federated learning has become increasingly
important for modern machine learning, especially for data privacy sensitive
scenarios. It is difficult to carry out secure machine learning between
heterogeneous data islands. A federated learning communication mode between
heterogeneous data islands is proposed, which realizes the hybrid federated
learning communication between horizontal and vertical, and breaks the
communication barrier of the disunity of model structure between horizontal and
vertical participants in traditional federated learning. Based on the special
privacy requirements of the government, banks and other institutions, the third
party aggregator is further removed on the basis of the hybrid federated
learning model, and the calculation is carried out only among the participants,
which greatly improves the privacy security of local data. In view of the
computational speed bottleneck caused by vertical homomorphic encryption in the
communication process in the above model, by increasing the local iteration
round q, the encryption time of vertical federation learning is shortened by
more than 10 times, and the computational bottleneck between horizontal and
vertical participants is reduced, and the accuracy loss is less than 5% .