CC BY 4.0 vs CC BY-SA 4.0
<p>I'm confused by the difference between CC BY 4.0 and CC BY-SA (4.0?)</p>

<p><strong>Context:</strong></p>

<p>I found some books shared with CC BY 4.0. I want to publish these books in my book-reading app (commercial product) but I need to make changes to it for my country's market and want to protect those changes. </p>

<p><strong><a href="https://creativecommons.org/licenses/by/4.0/" rel="nofollow noreferrer">CC BY 4.0</a> requires me to:</strong></p>

<ul>
<li>attribute original creators (I'm totally ok with that)</li>
<li>indicate if changes are made (I'm totally ok with that)</li>
</ul>

<p><strong>BUT it also requires me to link to the license.</strong> </p>

<p>I would think that "linking to the original license (CC BY)" is confusing if I don't want to license it under the same license terms (since it is not a SA (Share Alike) license. How would I go about doing this? 
Would something like "This work was originally shared under CC BY 4.0, the work it it's adapted form is now shared under CC BY-NC-ND" suffice? Do you have an example for such a case?</p>

<p><strong>AND it also requires me to not apply any legal terms or technological measures that legally restrict others from doing anything the license permits.</strong></p>

<p>I don't really get this. The CC BY is <strong>not</strong> as SA (Share Alike) license so I could share it differently. This to me suggests I would be able to restrict it's useage. Not being able to apply restricting legal terms seems like a contradition. </p>

<p>The core issue here is: do you have (partial) copyright in the work?</p>

<ul>
<li><p>without copyright, you have no right to issue a license – but you can pass on the same license you received</p></li>
<li><p>when you made an adaptation to the work you hold partial copyright, but your choice of license depends on the license you received for the original work</p>

<ul>
<li>under CC-BY you can license your adaptation under any license, as long as this doesn't prevent exercise of recipient's rights under the original license with respect to the original work. Compliance is simplified by staying in the CC license ecosystem, e.g by using CC-BY, CC-BY-NC, or CC-BY-ND.</li>
<li>under CC-BY-SA you can only license your adaptations under a compatible license, such as CC-BY-SA of the same or later version.</li>
</ul></li>
</ul>

<p>Format-shifting, changing the presentation of the work, or purely mechanical transformations likely does not constitute a creative work that would give you any copyright.</p>

<p>If you have an app like an e-book reader, the license of the content is completely separate from the license of the app. You're not required to license your app on any way or to make it free, but you have to comply with the license of the content – such as pointing users to the website of the work, if any. The precise contents of an attribution notice are enumerated in the full license text, only reading summaries might be confusing.</p>

<p>Regarding the interplay between your adaptions and the CC-BY 4.0 licensed original work:</p>

<ul>
<li>the work you have created combines both your adaptions and parts of the original work

<ul>
<li>what changes are considered copyrightable depends on your jurisdiction, but manual translation generally counts</li>
</ul></li>
<li>the recipient receives a full license to the original work, to which you are not party and are not allowed to apply downstream restrictions (section 2.a.5)</li>
<li>you can choose any license you want for your adaptions as long as it doesn't prevent compliance with the license of the original parts (section 3.a.4)

<ul>
<li>e.g. an incompatible term would be to forbid recipients from disclosing the origin of the original version</li>
<li>you <em>can</em> apply DRM to your parts, but they are usually not separable from the original parts. Therefore, consider offering the original version in a DRM-free manner, e.g. by linking to the original.</li>
</ul></li>
<li><p>regardless of your chosen license, you must provide attribution per section 3.a. A complete notice for a translated e-book might read:</p>

<blockquote>
  <p>"Title of the Translated Book"<br>
  Translation by Your Name<br>
  Copyright YEAR Your Name  </p>
  
  <p>Translated from: "original title" by ?Original Author ?(link to original)<br>
  ?Copyright YEAR Original Author<br>
  ?Disclaimer: ...<br>
  Licensed under CC-BY 4.0 (link to license)</p>
  
  <p>?Info about previous modifications</p>
</blockquote>

<p>(items prefixed with <code>?</code> only have to be shown if the original licensor supplied them, but it's best to include them to the fullest degree possible)</p></li>
</ul>

copyright creative-commons