**6. Lightweight cryptography**

To measure the performance of lightweight algorithms, there are some performance metrics are described below.


4.**Latency:** Latency is defined as the total time required to complete a task. Here the number of clock cycles required for encryption of a single block message is defined as N. So, the latency is defined by:

Latency = N ∗ CriticalPathoftheCircuit

5.**Power and energy consumption:** Power consumption is dependent on the operating frequency, critical path, and so on the execution time. The unit used to define power consumption is W. For hardware implementation power calculation is done by using GE and operating frequency. Energy consumption per bit can be calculated as and the unit used is J:

Energy = Latency ∗ Power/blocksize.

**RAM/ROM memory:** Total RAM or ROM memory required in bytes to execute the algorithm.

6.**Efficiency:** This is a trade-off between the performance of the algorithm and the cost to implement it. For hardware implementation, the efficiency can be calculated as:

Efficiency = Throughput/Complexity.

Complexity in terms of chip area is defined by GE and so the unit used to define complexity is KGE. For a software implementation, the efficiency can be calculated as:

Efficiency = Throughput/Codesize.

In this case, code size is defined in KB.
