Reverse engineering of Java Card applets using power analysis

Faculty of Electrical Engineering, Mathematics and Computer Science CE-MS-2006-05 Power analysis of smart cards is commonly used to obtain information about implemented cryptographic algorithms. We propose a similar methodology for reverse engineering of Java Card applets. In order to acquire power traces, we present a new microcontroller based smart card reader with an accurate adjustable trigger function. Because power analysis only does not provide enough information, we refine our methodology by involving additional information sources. Issues like distinguishing between instructions performing similar tasks and reverse engineering of conditional branches and nested loops are also addressed. The proposed methodology is applied to a commercially available Java Card smart card and the results are reported. We conclude that our augmented power analysis can be successfully used to acquire information about the instructions executed on a Java Card smart card. Reverse engineering of Java Card applets using power analysis