Why does the decode function of the segwit bech32 encoder/decoder take a hrp (human readable part) as input?












1














Looking at the code referenced in bip-0173, specifically for example here:
https://github.com/sipa/bech32/blob/master/ref/javascript/segwit_addr.js



  function decode (hrp, addr) {

      var dec = bech32.decode(addr);

      if (dec === null || dec.hrp !== hrp || dec.data.length < 1 || dec.data[0] > 16) {

        return null;

      }

      ...


I understand that this is an error checking statement, but why check a (user?) inputted hrp vs the decoded hrp from bech32.decode?



Also I'm assuming that the "dec.data[0] > 16" check is to make sure that the byte at index zero doesn't exceed a value of 16, which would be invalid hex. Is this correct?






segregated-witness bech32-address







share|improve this question



























    1














    Looking at the code referenced in bip-0173, specifically for example here:
    https://github.com/sipa/bech32/blob/master/ref/javascript/segwit_addr.js



      function decode (hrp, addr) {
    
      var dec = bech32.decode(addr);
    
      if (dec === null || dec.hrp !== hrp || dec.data.length < 1 || dec.data[0] > 16) {
    
        return null;
    
      }
    
      ...


    I understand that this is an error checking statement, but why check a (user?) inputted hrp vs the decoded hrp from bech32.decode?



    Also I'm assuming that the "dec.data[0] > 16" check is to make sure that the byte at index zero doesn't exceed a value of 16, which would be invalid hex. Is this correct?






    segregated-witness bech32-address







    share|improve this question

























      1












      1








      1







      Looking at the code referenced in bip-0173, specifically for example here:
      https://github.com/sipa/bech32/blob/master/ref/javascript/segwit_addr.js



        function decode (hrp, addr) {
      
      var dec = bech32.decode(addr);
      
      if (dec === null || dec.hrp !== hrp || dec.data.length < 1 || dec.data[0] > 16) {
      
        return null;
      
      }
      
      ...


      I understand that this is an error checking statement, but why check a (user?) inputted hrp vs the decoded hrp from bech32.decode?



      Also I'm assuming that the "dec.data[0] > 16" check is to make sure that the byte at index zero doesn't exceed a value of 16, which would be invalid hex. Is this correct?






      segregated-witness bech32-address







      share|improve this question













      Looking at the code referenced in bip-0173, specifically for example here:
      https://github.com/sipa/bech32/blob/master/ref/javascript/segwit_addr.js



        function decode (hrp, addr) {
      
      var dec = bech32.decode(addr);
      
      if (dec === null || dec.hrp !== hrp || dec.data.length < 1 || dec.data[0] > 16) {
      
        return null;
      
      }
      
      ...


      I understand that this is an error checking statement, but why check a (user?) inputted hrp vs the decoded hrp from bech32.decode?



      Also I'm assuming that the "dec.data[0] > 16" check is to make sure that the byte at index zero doesn't exceed a value of 16, which would be invalid hex. Is this correct?






      segregated-witness bech32-address




      segregated-witness bech32-address






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked 5 hours ago









      kawthuldrokkawthuldrok

      467




      467






















          2 Answers
          2






          active

          oldest

          votes


















          3














          The HRP is part of the bech32 encoded string, and in the bech32 decoding API, it is returned along with the payload by the decoder, after checking the checksum.



          We still want to compare it with the expected HRP in BIP173, which encodes the chain the software is operating on.



          Otherwise you could have a testnet node that accepts mainnet BIP173 addresses or the other way around.






          share|improve this answer





























            1















            I'm assuming that the "dec.data[0] > 16" check is to make sure that the byte at index zero doesn't exceed a value of 16, which would be invalid hex. Is this correct?




            No, it's because only versions 0 - 16 are specified. Other versions might behave entirely differently. (As an aside, if it were a comparison for the sake of clamping to the range of a single hex character the test would be >15 not >16).






            share|improve this answer





















              Your Answer








              StackExchange.ready(function() {
              var channelOptions = {
              tags: "".split(" "),
              id: "308"
              };
              initTagRenderer("".split(" "), "".split(" "), channelOptions);

              StackExchange.using("externalEditor", function() {
              // Have to fire editor after snippets, if snippets enabled
              if (StackExchange.settings.snippets.snippetsEnabled) {
              StackExchange.using("snippets", function() {
              createEditor();
              });
              }
              else {
              createEditor();
              }
              });

              function createEditor() {
              StackExchange.prepareEditor({
              heartbeatType: 'answer',
              autoActivateHeartbeat: false,
              convertImagesToLinks: false,
              noModals: true,
              showLowRepImageUploadWarning: true,
              reputationToPostImages: null,
              bindNavPrevention: true,
              postfix: "",
              imageUploader: {
              brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
              contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
              allowUrls: true
              },
              noCode: true, onDemand: true,
              discardSelector: ".discard-answer"
              ,immediatelyShowMarkdownHelp:true
              });


              }
              });














              draft saved

              draft discarded


















              StackExchange.ready(
              function () {
              StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fbitcoin.stackexchange.com%2fquestions%2f83454%2fwhy-does-the-decode-function-of-the-segwit-bech32-encoder-decoder-take-a-hrp-hu%23new-answer', 'question_page');
              }
              );

              Post as a guest















              Required, but never shown

























              2 Answers
              2






              active

              oldest

              votes








              2 Answers
              2






              active

              oldest

              votes









              active

              oldest

              votes






              active

              oldest

              votes









              3














              The HRP is part of the bech32 encoded string, and in the bech32 decoding API, it is returned along with the payload by the decoder, after checking the checksum.



              We still want to compare it with the expected HRP in BIP173, which encodes the chain the software is operating on.



              Otherwise you could have a testnet node that accepts mainnet BIP173 addresses or the other way around.






              share|improve this answer


























                3














                The HRP is part of the bech32 encoded string, and in the bech32 decoding API, it is returned along with the payload by the decoder, after checking the checksum.



                We still want to compare it with the expected HRP in BIP173, which encodes the chain the software is operating on.



                Otherwise you could have a testnet node that accepts mainnet BIP173 addresses or the other way around.






                share|improve this answer
























                  3












                  3








                  3






                  The HRP is part of the bech32 encoded string, and in the bech32 decoding API, it is returned along with the payload by the decoder, after checking the checksum.



                  We still want to compare it with the expected HRP in BIP173, which encodes the chain the software is operating on.



                  Otherwise you could have a testnet node that accepts mainnet BIP173 addresses or the other way around.






                  share|improve this answer












                  The HRP is part of the bech32 encoded string, and in the bech32 decoding API, it is returned along with the payload by the decoder, after checking the checksum.



                  We still want to compare it with the expected HRP in BIP173, which encodes the chain the software is operating on.



                  Otherwise you could have a testnet node that accepts mainnet BIP173 addresses or the other way around.







                  share|improve this answer












                  share|improve this answer



                  share|improve this answer










                  answered 4 hours ago









                  Pieter WuillePieter Wuille

                  45.6k393154




                  45.6k393154























                      1















                      I'm assuming that the "dec.data[0] > 16" check is to make sure that the byte at index zero doesn't exceed a value of 16, which would be invalid hex. Is this correct?




                      No, it's because only versions 0 - 16 are specified. Other versions might behave entirely differently. (As an aside, if it were a comparison for the sake of clamping to the range of a single hex character the test would be >15 not >16).






                      share|improve this answer


























                        1















                        I'm assuming that the "dec.data[0] > 16" check is to make sure that the byte at index zero doesn't exceed a value of 16, which would be invalid hex. Is this correct?




                        No, it's because only versions 0 - 16 are specified. Other versions might behave entirely differently. (As an aside, if it were a comparison for the sake of clamping to the range of a single hex character the test would be >15 not >16).






                        share|improve this answer
























                          1












                          1








                          1







                          I'm assuming that the "dec.data[0] > 16" check is to make sure that the byte at index zero doesn't exceed a value of 16, which would be invalid hex. Is this correct?




                          No, it's because only versions 0 - 16 are specified. Other versions might behave entirely differently. (As an aside, if it were a comparison for the sake of clamping to the range of a single hex character the test would be >15 not >16).






                          share|improve this answer













                          I'm assuming that the "dec.data[0] > 16" check is to make sure that the byte at index zero doesn't exceed a value of 16, which would be invalid hex. Is this correct?




                          No, it's because only versions 0 - 16 are specified. Other versions might behave entirely differently. (As an aside, if it were a comparison for the sake of clamping to the range of a single hex character the test would be >15 not >16).







                          share|improve this answer












                          share|improve this answer



                          share|improve this answer










                          answered 4 hours ago









                          G. MaxwellG. Maxwell

                          3,3821630




                          3,3821630






























                              draft saved

                              draft discarded




















































                              Thanks for contributing an answer to Bitcoin Stack Exchange!


                              • Please be sure to answer the question. Provide details and share your research!

                              But avoid …



                              • Asking for help, clarification, or responding to other answers.

                              • Making statements based on opinion; back them up with references or personal experience.


                              To learn more, see our tips on writing great answers.





                              Some of your past answers have not been well-received, and you're in danger of being blocked from answering.


                              Please pay close attention to the following guidance:


                              • Please be sure to answer the question. Provide details and share your research!

                              But avoid …



                              • Asking for help, clarification, or responding to other answers.

                              • Making statements based on opinion; back them up with references or personal experience.


                              To learn more, see our tips on writing great answers.




                              draft saved


                              draft discarded














                              StackExchange.ready(
                              function () {
                              StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fbitcoin.stackexchange.com%2fquestions%2f83454%2fwhy-does-the-decode-function-of-the-segwit-bech32-encoder-decoder-take-a-hrp-hu%23new-answer', 'question_page');
                              }
                              );

                              Post as a guest















                              Required, but never shown





















































                              Required, but never shown














                              Required, but never shown












                              Required, but never shown







                              Required, but never shown

































                              Required, but never shown














                              Required, but never shown












                              Required, but never shown







                              Required, but never shown







                              -

                              Popular posts from this blog

                              A CLEAN and SIMPLE way to add appendices to Table of Contents and bookmarks

                              Image
                              0 I found a lot of questions abount appendices and ToC. Many users want appendices to be grouped in an Appendix part, however some problems arise with ToC, hyperref, PDF viewer bookmarks, and so on. There are different solutions which require extra packages, command patching and other extra code, however none of them satisfies me. I almost found an easy way to accomplish a good result, where appendices are added to bookmarks in the right way and hyperref links point to the right page. However, the number of the "Appendix" part page is wrong (it's the number of appendix A). Is there any EASY way to fix that? This is a MWE: documentclass{book} usepackage[nottoc,notlot,notlof]{tocbibind} usepackage{hyperref} begin{document} frontmatter tableofcontents mainmatter part{First} chapter{...
                              Read more

                              Calculate evaluation metrics using cross_val_predict sklearn

                              Image
                              1 In the sklearn.model_selection.cross_val_predict page it is stated: Generate cross-validated estimates for each input data point. It is not appropriate to pass these predictions into an evaluation metric. Can someone explain what does it mean? If this gives estimate of Y (y prediction) for every Y (true Y), why can't I calculate metrics such as RMSE or coefficient of determination using these results? python scikit-learn cross-validation share | improve this question edited Nov 28 '18 at 17:52 desertnaut 20.3k 7 43 79 ...
                              Read more

                              Insert data from modal to MySQL (multiple modal on website)

                              Image
                              0 I have problem with inserting data to MySQL from modal. My modal: <a href="#" class="badge badge-pill badge-success">6 komentarzy</a> <a href="#" class="badge badge-pill badge-danger">brak komentarzy</a> <a data-toggle="modal" href="#add_desk_comm_{$desk_['desk_id']}" data-target="#add_desk_comm_{$desk_['desk_id']}" class="ediiit">(dodaj)</a> <div class="modal fade" id="add_desk_comm_{$desk_['desk_id']}" tabindex="-1" role="dialog" aria-labelledby="edit_printer" aria-hidden="true"> <div class="modal-dialog" role="document"> ...
                              Read more