What is blacklist? How it works?

The blacklist (or black list or negative list) is a way of grouping bad information and should be discarded immediately. It is understood that all records contained in the blacklist have already been confirmed as being bad, either by an algorithm or a person.

In order analysis, it is used to deny any request that contains those data - for example, an email that we already know to be a fraudster or an address that often results in disputes.