Merge pull request #916 from daira/zip-244-clarification

ZIP 244: clarify that shielded inputs can't just sign the txid if there are transparent inputs

rendered/zip-0244.html

@@ -233,7 +233,7 @@
                     </section>
                 </section>
                 <section id="signature-digest"><h4><span class="section-heading">Signature Digest</span><span class="section-anchor"> <a rel="bookmark" href="#signature-digest"><img width="24" height="24" class="section-anchor" src="assets/images/section-anchor.png" alt=""></a></span></h4>
-                    <p>A new per-input transaction digest algorithm is defined that constructs a hash that may be signed by a transaction creator to commit to the effects of the transaction. A signature digest is produced for each transparent input, each Sapling input, and each Orchard action. For transparent inputs, this follows closely the algorithms from ZIP 143 <a id="footnote-reference-10" class="footnote_reference" href="#zip-0143">6</a> and ZIP 243 <a id="footnote-reference-11" class="footnote_reference" href="#zip-0243">7</a>. For shielded inputs, this algorithm has the exact same output as the transaction digest algorithm, thus the txid may be signed directly.</p>
+                    <p>A new per-input transaction digest algorithm is defined that constructs a hash that may be signed by a transaction creator to commit to the effects of the transaction. A signature digest is produced for each transparent input, each Sapling input, and each Orchard action. This follows closely the algorithms from ZIP 143 <a id="footnote-reference-10" class="footnote_reference" href="#zip-0143">6</a> and ZIP 243 <a id="footnote-reference-11" class="footnote_reference" href="#zip-0243">7</a>. For transactions without transparent inputs, this algorithm has the exact same output as the transaction digest algorithm, thus the txid may be signed directly.</p>
                     <p>The overall structure of the hash is as follows; each name referenced here will be described in detail below:</p>
                     <pre>signature_digest
 ├── header_digest

zips/zip-0244.rst

@@ -453,9 +453,9 @@ Signature Digest
 A new per-input transaction digest algorithm is defined that constructs a hash that may be
 signed by a transaction creator to commit to the effects of the transaction. A signature
 digest is produced for each transparent input, each Sapling input, and each Orchard
-action. For transparent inputs, this follows closely the algorithms from ZIP 143 [#zip-0143]_
-and ZIP 243 [#zip-0243]_. For shielded inputs, this algorithm has the exact same output
-as the transaction digest algorithm, thus the txid may be signed directly.
+action. This follows closely the algorithms from ZIP 143 [#zip-0143]_ and ZIP 243 [#zip-0243]_.
+For transactions without transparent inputs, this algorithm has the exact same output as
+the transaction digest algorithm, thus the txid may be signed directly.
 
 The overall structure of the hash is as follows; each name referenced here will be
 described in detail below::