This is a library for converting between bitcoin transaction IDs (TxIDs), bitcoin transaction coordinates (blockHeight, transactionIndex, and txoIndex), and "Bech32 Encoded Tx Position References" (TxRefs). TxRefs are described in BIP 0136.
See the full code for the following examples.
int blockHeight = 10000;
int transactionIndex = 2;
std::string txref = txref::encode(blockHeight, transactionIndex);
assert(txref == "tx1:rq3n-qqzq-qk8k-mzd"); int blockHeight = 10000;
int transactionIndex = 4;
std:string txref = txref::encodeTestnet(blockHeight, transactionIndex);
assert(txref == "txtest1:xq3n-qqyq-qhrg-gy3");Create an extended txref for a mainnet transaction, with a blockHeight, transactionIndex, and txoIndex:
int blockHeight = 10000;
int transactionIndex = 2;
int txoIndex = 3;
std::string txref = txref::encode(blockHeight, transactionIndex, txoIndex);
assert(txref == "tx1:yq3n-qqzq-qrqq-9z4d-2n");Create an extended txref for a testnet transaction, with a blockHeight, transactionIndex, and txoIndex
int blockHeight = 10000;
int transactionIndex = 4;
int txoIndex = 6;
std::string txref = txref::encodeTestnet(blockHeight, transactionIndex, txoIndex);
assert(txref == "txtest1:8q3n-qqyq-qxqq-v3x4-ze");See the full code for the following examples.
txref::DecodedResult decodedResult = txref::decode("tx1:yq3n-qqzq-qrqq-9z4d-2n");
assert(decodedResult.hrp == "tx");
assert(decodedResult.magicCode == txref::MAGIC_CODE_MAIN_EXTENDED);
assert(decodedResult.blockHeight == 10000);
assert(decodedResult.transactionIndex == 2);
assert(decodedResult.txoIndex == 3);
assert(decodedResult.encoding == txref::Encoding::Bech32m);This txref has been encoded with the original bech32 internal constant. The decoding will still succeed, but the library will also return a commentary string that contains an explanatory message along with the txref that should be used instead.
txref::DecodedResult decodedResult = txref::decode("txtest1:xjk0-uqay-zat0-dz8");
assert(decodedResult.hrp == "txtest");
assert(decodedResult.magicCode == txref::MAGIC_CODE_TEST);
assert(decodedResult.blockHeight == 466793);
assert(decodedResult.transactionIndex == 2205);
assert(decodedResult.txoIndex == 0);
assert(decodedResult.encoding == txref::Encoding::Bech32); // note: Bech32 rather than Bech32m
std::cout << decodedResult.commentary << "\n";
// prints:
// "The txref txtest1:xjk0-uqay-zat0-dz8 uses an old encoding scheme and should be updated to txtest1:xjk0-uqay-zghl-p89 See https://github.com/dcdpr/libtxref#regarding-bech32-checksums for more information."See the full code for the following example.
int blockHeight = 10000;
int transactionIndex = 2;
int txoIndex = 3;
char main_hrp[] = "tx";
txref_tstring * tstring = txref_create_tstring();
if(!tstring)
return E_TXREF_NO_MEMORY;
txref_error err = txref_encode(tstring, blockHeight, transactionIndex, txoIndex, false, main_hrp);
if(err != E_TXREF_SUCCESS) {
txref_free_tstring(tstring);
return err;
}
assert(strcmp(tstring->string, "tx1:yq3n-qqzq-qrqq-9z4d-2n") == 0);
txref_free_tstring(tstring);See the full code for the following example.
char txref[] = "tx1:yq3n-qqzq-qrqq-9z4d-2n";
txref_DecodedResult *decodedResult = txref_create_DecodedResult();
if(!decodedResult)
return E_TXREF_NO_MEMORY;
txref_error err = txref_decode(decodedResult, txref);
if(err != E_TXREF_SUCCESS) {
txref_free_DecodedResult(decodedResult);
return err;
}
assert(decodedResult->blockHeight == 10000);
assert(decodedResult->transactionIndex == 2);
assert(decodedResult->txoIndex == 3);
txref_free_DecodedResult(decodedResult);To build libtxref, you will need:
- cmake
- g++, clang or Visual Studio (community edition)
libtxref uses a pretty standard cmake build system:
mkdir build
cd build
cmake ..
make
You can also run all the tests:
make test
If the above doesn't work, you probably need to install some prerequisites. For example, on a fresh Debian 10 ("buster") system:
sudo apt-get update
sudo apt-get install make gcc g++
It is worth getting the latest cmake (check cmake.org for the latest release), so install that the hard way:
sudo apt-get install libssl-dev # recent cmake needs ssl
wget https://github.com/Kitware/CMake/releases/download/v3.20.1/cmake-3.20.1.tar.gz
wget https://github.com/Kitware/CMake/releases/download/v3.20.1/cmake-3.20.1-SHA-256.txt
shasum -a 256 --ignore-missing -c cmake-3.20.1-SHA-256.txt # make sure this says "OK"
tar xzf cmake-3.20.1.tar.gz
cd cmake-3.20.1
./configure
make
sudo make install
Now you can again try to build libtxref.
If you got this code by cloning the github repo:
git clone https://github.com/dcdpr/libtxref.git
then you will need to do a few extra steps to make sure you have everything:
cd libbech32
git submodule init
git submodule update
There is another way to do this which is a little simpler, however. If you pass --recurse-submodules to the git clone command, it will automatically initialize and update each submodule in the repository:
git clone --recurse-submodules https://github.com/dcdpr/libtxref.git
The Bech32 data encoding format was first proposed by Pieter Wuille in early 2017 in BIP 0173. Later, in November 2019, Pieter published some research that a constant 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 reporting that "exhaustive analysis" showed the best possible constant value is 0x2bc830a3. This improved variant of Bech32 is called "Bech32m".
When decoding a txref, libtxref returns an enum value showing whether bech32m or bech32 was used to encode. If the original bech32 variant is detected, libtxref also returns a commentary string that can be shown to the user. This commentary will contain a new txref that represents the same transaction data, but using the new bech32m variant. This can be seen in the examples above.
When encoding data, libtxref will only use the new constant value of 0x2bc830a3.