Blacklist (computing)

In computing, a "blacklist" is a list of entities, such as IP addresses, email addresses, or applications, that are explicitly blocked or denied access to a system or network. This is often used as a security measure to prevent malicious activities, spam, or unwanted content. When an entity is on a blacklist, it is automatically barred from certain actions or interactions, while everything not on the list is typically allowed. Blacklisting helps protect systems from potential threats and ensures safer online environments.