Updates bech32 checksum constant to "M" #3
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…m; update all cpp tests and examples
add some new functions to c api; update all c tests and examples add missing header file for gcc
dcdpr
reviewed
Feb 12, 2021
| [BIP 0173](https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki). Later, in November 2019, Pieter published | ||
| some research regarding that an exponent used in the bech32 checksum algorithm (value = 1) may not be | ||
| optimal for the error detecting properties of bech32. In February 2021, Pieter published | ||
| [BIP 0350](http://www.example.com) reporting that "exhaustive analysis" showed the best possible exponent value is |
dcdpr
reviewed
Feb 12, 2021
| 0x2bc830a3. This improved variant of Bech32 is called "Bech32m". | ||
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| When decoding a possible bech32 encoded string, libbech32 returns an enum value showing whether bech32m or bech32 | ||
| was used to encode. This can be seen in the exaples above. |
dcdpr
reviewed
Feb 12, 2021
| @@ -7,15 +7,15 @@ namespace { | |||
| using namespace bech32::limits; | |||
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| // exponent used in checksum generation, taken from recommendation | |||
| // in: https://gist.github.com/sipa/a9845b37c1b298a7301c33a04090b2eb | |||
| const unsigned int M = 0x3FFFFFFF; | |||
| // in: https://github.com/sipa/bips/blob/bip-bech32m/bip-bech32m.mediawiki | |||
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link broken. ready to point to bip350.
https://github.com/bitcoin/bips/blob/master/bip-0350.mediawiki
sipa's working blob has moved here (but may be already abandoned):
https://github.com/sipa/bips/blob/6446f2af0a75e513a0c4bad0ddaad8d798bd5e2d/bip-0350.mediawiki
dcdpr
reviewed
Feb 12, 2021
| inputStr.length() - (index_of_separator+1) - bech32::limits::CHECKSUM_LENGTH; // +1 for zero-based index | ||
| inputStr.length() | ||
| - number_of_hrp_characters | ||
| - 1 // for separator character |
dcdpr
reviewed
Feb 12, 2021
| free(hrpdp); | ||
| void bech32_free_HrpAndDp(bech32_HrpAndDp *hrpAndDp) { | ||
| if(hrpAndDp == nullptr) | ||
| return; |
dcdpr
reviewed
Feb 12, 2021
| extern "C" | ||
| void bech32_free_bstring(bech32_bstring *bstring) { | ||
| if(bstring == nullptr) | ||
| return; |
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same Q here: is the program working well if it frees a null pointer?
discussion:
https://stackoverflow.com/questions/4190703/is-it-safe-to-delete-a-null-pointer#comment34158001_4190737
dcdpr
reviewed
Feb 12, 2021
| * @param dp pointer to the "data part" | ||
| * @param dplen the length of the "data part" array | ||
| * | ||
| * @return E_BECH32_SUCCESS on success, others on error (hrp/dp/bstr is NULL, bstr not | ||
| * @return E_BECH32_SUCCESS on success, others on error (i.e., hrp/dp/bstring is NULL, bstring not |
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grammar nazi: i think you mean e.g.
dcdpr
reviewed
Feb 12, 2021
| * | ||
| * @return E_BECH32_SUCCESS on success, others on error (hrp/dp/bstr is NULL, hrp/dp not | ||
| * @return E_BECH32_SUCCESS on success, others on error (i.e., output is NULL, hrp/dp not |
dcdpr
reviewed
Feb 12, 2021
| @@ -481,11 +634,12 @@ bech32_error bech32_decode(bech32_HrpAndDp *output, char const *bstr, size_t bst | |||
| if(hrpAndDp.hrp.empty() && hrpAndDp.dp.empty()) | |||
| return E_BECH32_INVALID_CHECKSUM; | |||
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| if(hrpAndDp.hrp.size() > output->hrplen-1) | |||
| if(hrpAndDp.hrp.size() > output->hrplen) | |||
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i see, so this wasn't a prior bug, but was a consequence of clarifying the semantics of hrplen.
dcdpr
reviewed
Feb 12, 2021
| b = splitString(data); | ||
| convertToLowercase(b.hrp); | ||
| mapDP(b.dp); | ||
| ASSERT_TRUE(verifyChecksum(b.hrp, b.dp)); | ||
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| data = "11qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq8c42pv"; | ||
| data = "11llllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllludsr8"; |
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what happens if the many-q-string is sent in now?
dcdpr
approved these changes
Feb 12, 2021
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This PR contains all changes needed to update the bech32 algorithm's exponential constant from the original value of "1", then the intermediate value of "0x3FFFFFFF", to the now final value of "0x2bc830a3". This final value, also known as "M", was decided upon following the recent research by Pieter Wuille, currently seen here: https://github.com/sipa/bips/blob/bip-bech32m/bip-bech32m.mediawiki
Also included are quite a few updates to the C API as I discovered a few memory leaks during my testing of the new constant.
Some items to consider: HrpAndDp is a crappy struct name for the decoded "human readable" and "data" parts. Can you suggest something better? I'm also not terribly fond of the function name "encodeUsingOriginalConstant()" which goes along with the default of "encode()".