This document discusses algorithms for detecting credit card fraud. It compares the performance of two algorithms: random forest and K-nearest neighbors (KNN). Random forest uses decision trees to classify transactions as normal or fraudulent based on attributes of past transactions. KNN compares new transactions to historical ones based on attributes. The document tests these algorithms on a real-world credit card transaction dataset. It finds that random forest obtains good results on smaller datasets but has issues with imbalanced data. The authors' future work will focus on addressing these issues and improving the random forest algorithm.