doc/shared-libraries.md

   1 Shared Libraries
   2 ================
   3
   4 ## bitcoinconsensus
   5
   6 The purpose of this library is to make the verification functionality that is critical to Bitcoin's consensus available to other applications, e.g. to language bindings.
   7
   8 ### API
   9
  10 The interface is defined in the C header `bitcoinconsensus.h` located in  `src/script/bitcoinconsensus.h`.
  11
  12 #### Version
  13
  14 `bitcoinconsensus_version` returns an `unsigned int` with the API version *(currently at an experimental `0`)*.
  15
  16 #### Script Validation
  17
  18 `bitcoinconsensus_verify_script` returns an `int` with the status of the verification. It will be `1` if the input script correctly spends the previous output `scriptPubKey`.
  19
  20 ##### Parameters
  21 - `const unsigned char *scriptPubKey` - The previous output script that encumbers spending.
  22 - `unsigned int scriptPubKeyLen` - The number of bytes for the `scriptPubKey`.
  23 - `const unsigned char *txTo` - The transaction with the input that is spending the previous output.
  24 - `unsigned int txToLen` - The number of bytes for the `txTo`.
  25 - `unsigned int nIn` - The index of the input in `txTo` that spends the `scriptPubKey`.
  26 - `unsigned int flags` - The script validation flags *(see below)*.
  27 - `bitcoinconsensus_error* err` - Will have the error/success code for the operation *(see below)*.
  28
  29 ##### Script Flags
  30 - `bitcoinconsensus_SCRIPT_FLAGS_VERIFY_NONE`
  31 - `bitcoinconsensus_SCRIPT_FLAGS_VERIFY_P2SH` - Evaluate P2SH ([BIP16](https://github.com/bitcoin/bips/blob/master/bip-0016.mediawiki)) subscripts
  32 - `bitcoinconsensus_SCRIPT_FLAGS_VERIFY_DERSIG` - Enforce strict DER ([BIP66](https://github.com/bitcoin/bips/blob/master/bip-0066.mediawiki)) compliance
  33 - `bitcoinconsensus_SCRIPT_FLAGS_VERIFY_NULLDUMMY` - Enforce NULLDUMMY ([BIP147](https://github.com/bitcoin/bips/blob/master/bip-0147.mediawiki))
  34 - `bitcoinconsensus_SCRIPT_FLAGS_VERIFY_CHECKLOCKTIMEVERIFY` - Enable CHECKLOCKTIMEVERIFY ([BIP65](https://github.com/bitcoin/bips/blob/master/bip-0065.mediawiki))
  35 - `bitcoinconsensus_SCRIPT_FLAGS_VERIFY_CHECKSEQUENCEVERIFY` - Enable CHECKSEQUENCEVERIFY ([BIP112](https://github.com/bitcoin/bips/blob/master/bip-0112.mediawiki))
  36 - `bitcoinconsensus_SCRIPT_FLAGS_VERIFY_WITNESS` - Enable WITNESS ([BIP141](https://github.com/bitcoin/bips/blob/master/bip-0141.mediawiki))
  37
  38 ##### Errors
  39 - `bitcoinconsensus_ERR_OK` - No errors with input parameters *(see the return value of `bitcoinconsensus_verify_script` for the verification status)*
  40 - `bitcoinconsensus_ERR_TX_INDEX` - An invalid index for `txTo`
  41 - `bitcoinconsensus_ERR_TX_SIZE_MISMATCH` - `txToLen` did not match with the size of `txTo`
  42 - `bitcoinconsensus_ERR_DESERIALIZE` - An error deserializing `txTo`
  43 - `bitcoinconsensus_ERR_AMOUNT_REQUIRED` - Input amount is required if WITNESS is used
  44
  45 ### Example Implementations
  46 - [NBitcoin](https://github.com/NicolasDorier/NBitcoin/blob/master/NBitcoin/Script.cs#L814) (.NET Bindings)
  47 - [node-libbitcoinconsensus](https://github.com/bitpay/node-libbitcoinconsensus) (Node.js Bindings)
  48 - [java-libbitcoinconsensus](https://github.com/dexX7/java-libbitcoinconsensus) (Java Bindings)
  49 - [bitcoinconsensus-php](https://github.com/Bit-Wasp/bitcoinconsensus-php) (PHP Bindings)