Regular Paper

Journal of Cryptographic Engineering

, Volume 1, Issue 1, pp 5-27

First online:

Open Access This content is freely available online to anyone, anywhere at any time.

Introduction to differential power analysis

  • Paul KocherAffiliated withCryptography Research, Inc
  • , Joshua JaffeAffiliated withCryptography Research, Inc Email author 
  • , Benjamin JunAffiliated withCryptography Research, Inc
  • , Pankaj RohatgiAffiliated withCryptography Research, Inc


The power consumed by a circuit varies according to the activity of its individual transistors and other components. As a result, measurements of the power used by actual computers or microchips contain information about the operations being performed and the data being processed. Cryptographic designs have traditionally assumed that secrets are manipulated in environments that expose no information beyond the specified inputs and outputs. This paper examines how information leaked through power consumption and other side channels can be analyzed to extract secret keys from a wide range of devices. The attacks are practical, non-invasive, and highly effective—even against complex and noisy systems where cryptographic computations account for only a small fraction of the overall power consumption. We also introduce approaches for preventing DPA attacks and for building cryptosystems that remain secure even when implemented in hardware that leaks.


Differential power analysis DPA SPA Side-channel attacks Tamper resistance Cryptanalysis