A class should have only one responsibility
Responsibility is the work that has been assigned to the class. In the SOLID set of principles, the S stands for the SRP. When applied to a class, the SRP states that the class must only work on a single aspect of the feature being implemented. The responsibility of that single aspect should be fully encapsulated within the class. Therefore, you should never apply more than one responsibility to a class.
Let’s look at an example to understand why:
public class MultipleResponsibilities{
    public string DecryptString(
        string text,
        SecurityAlgorithm algorithm)
    {
        // ...implementation...
    }
    public string EncryptString(
        string text,
   ...
