In general, a whitelist means a list of people or things considered to be acceptable or trustworthy, for example, permitted and verified individuals, organizations, computer programs, or even cryptocurrency addresses. Therefore, depending on the context, whitelists can have different meanings.

For instance, users who subscribe to a cryptocurrency company's mailing list are frequently asked to add the company's email address to their whitelists. in order to prevent the emails from ending up in spam folders. In some other cases, businesses may also pay fees to have their emails whitelisted by Internet service providers so that they are not automatically marked as spam.

In a network security context, local area networks (LANs), for example, can create a list of trusted MAC addresses to prevent unauthorized access. Similarly, wireless internet routers can use whitelists to restrict Internet access to only known users.

Aside from that, the concept of whitelisting may be associated with a list of computer programs that are deemed safe to use. Many antivirus programs have a predefined list of trusted applications that will not be targeted during system scans, but users can also create their own whitelists.

Whitelists in the blockchain and cryptocurrency environment are either associated with Initial Coin Offering (ICO) events or with withdrawal addresses. In the case of ICO events, cryptocurrency projects may provide a whitelisting phase for investors who wish to participate in the token's public sale. As a result, any investor who wishes to participate in the ICO must provide personal information before being whitelisted which is usually done through a KYC procedure. Simply put, in cryptocurrency, whitelist is a list of people who have expressed an interest in participating in an ICO (Initial Coin Offering) and have registered their intention to purchase the new coins.

Meanwhile, when it comes to withdrawal addresses, a whitelist is a list of cryptocurrency addresses that users deem trustworthy. In that case, they would only be able to withdraw funds from their exchange account to the previously whitelisted addresses in order to to keep their funds safe from hackers.