SecureBoost \(+\) : Large Scale and High-Performance Vertical Federated Gradient Boosting Decision Tree

Gradient boosting decision tree (GBDT) is an ensemble machine learning algorithm that is widely used in industry. Due to the problem of data isolation and the requirement of privacy, many works try to use vertical federated learning to train machine learning models collaboratively between different data owners. SecureBoost is one of the most popular vertical federated learning algorithms for GBDT. However, to achieve privacy preservation, SecureBoost involves complex training procedures and time-consuming cryptography operations. This causes SecureBoost to be slow to train and does not scale to large-scale data. In this work, we propose SecureBoost+, a large-scale and high-performance vertical federated gradient boosting decision tree framework. SecureBoost+ is secure in the semi-honest model, which is the same as SecureBoost. SecureBoost+ can be scaled up to tens of millions of data samples faster than SecureBoost. SecureBoost+ achieves high performance through several novel optimizations for SecureBoost, including ciphertext operation optimization and the introduction of new training mechanisms. The experimental results show that SecureBoost+ is 6–35x faster than SecureBoost but with the same accuracy and can be scaled up to tens of millions of data samples and thousands of feature dimensions.