Authentication is a method of verifying a user's identity. It involves ensuring that someone claiming to be who they say they are is actually who they say they are. It is a fundamental part of online interactions: The ability to verify a person's identity is essential for accessing a resource (such as a website or database) or using a service (such as Facebook).
This applies, for example, to logging into your bank account via Internet banking and the steps you take in the process. In order for customers to feel secure when using their accounts online, they need to make sure who they are. In short, authentication ensures that you are dealing with who you think you are.
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