As mentioned earlier, one of the basic parameters for knowledge to be considered open is that it is published under an open license or a public domain declaration. In the case of the former, these types of licenses allow information to be redistributed and reused with few restrictions. In other words, open licenses indicate to a person or organization that the content can be used under certain conditions established by the author and the type of open license used. On the other hand, information published under a public domain declaration can be used and exploited freely, without any permission, while respecting the author's integrity. This tool allows the creator of a work to waive their copyright and place it in the public domain. Both terms are embedded within open access, making information more useful by allowing a greater number of people to make use of it.
To delve deeper into open licenses, it must be mentioned that there are a variety of them; however, the most well-known and widely used are those offered by Creative Commons, an international nonprofit organization that seeks to share technical, legal, and policy solutions to benefit the exchange of knowledge. Creative Commons open licenses allow the use of a work but under certain conditions, ensuring that the content remains protected. In other words, if an author wishes to post their work on the internet to reach a wider audience, they can use one of these licenses, which must be attached to their work so that the public can identify the usage conditions chosen by the author when accessing the open content.
There are six types of open licenses, which are presented in the following table:
