A list of authorized and recognized people, organizations, computer programs, or even cryptocurrency addresses is referred to as a "whitelist." Whitelists typically pertain to a specific product, occasion, or piece of data. Whitelists can thus convey many connotations depending on the context in which they are employed. For instance, when users sign up for a company's mailing list, they are frequently prompted to add the company's email address to their whitelist in order to prevent the messages from going straight to the users' spam boxes. To avoid having their emails automatically classified as spam, businesses may occasionally pay fees to have their emails included in Internet service providers' whitelists. Users can ensure that future emails will arrive in their inboxes by adding an email address to their whitelist. Whitelists can be applied to network security situations as well. Local area networks (LANs), for instance, can create a list of trusted MAC addresses to prevent outsiders from connecting to them. Similarly to this, wireless internet routers can employ whitelists to restrict access to the connection to only known users. A list of computer programs that are deemed safe to use may also be related to the idea of whitelisting. Although users can manually build whitelists, many antivirus programs feature predefined lists of trusted programs that won't be targeted during system scans. Last but not least, in the context of blockchain technology and cryptocurrencies, whitelists are either associated with Initial Coin Offering (ICO) activities or with withdrawal addresses. For investors who are ready to take part in the public sale of their tokens, cryptocurrency projects may offer a whitelisting phase in the first scenario. Therefore, before being whitelisted, any investor who wishes to take part in the ICO must disclose their personal information (this is typically done through a KYC procedure). A list of cryptocurrency addresses that people deem to be reliable is referred to as a whitelist when discussing withdrawal addresses. They would then be restricted to making withdrawals from their exchange account to the addresses that had previously been whitelisted.