DPA meaning in Physics Related ?

In cryptography, a side channel attack is used to extract secret data from some secure device (such as a smart card, tamper-resistant "black box", or integrated circuit). Side-channel analysis is typically trying to non-invasively extract cryptographic keys and other secret information from the device. A simple example of this is the German tank problem: the serial numbers of tanks provide details of the production data for tanks. In physical security, a non-invasive attack would be similar to lock-picking, where a successful attack leaves no trace of the attacker being present.

Power analysis is a form of side channel attack in which the attacker studies the power consumption of a cryptographic hardware device. These attacks rely on basic physical properties of the device: semiconductor devices are governed by the laws of physics, which dictate that changes in voltages within the device require very small movements of electric charges (currents). By measuring those currents, it is possible to learn a small amount of information about the data being manipulated.

Simple power analysis (SPA) involves visually interpreting power traces, or graphs of electrical activity over time. Differential power analysis (DPA) is a more advanced form of power analysis, which can allow an attacker to compute the intermediate values within cryptographic computations through statistical analysis of data collected from multiple cryptographic operations. SPA and DPA were introduced to the open cryptography community in 1998 by Paul Kocher, Joshua Jaffe and Benjamin Jun.