/ doc / shared-libraries.md
shared-libraries.md
 1  Shared Libraries
 2  ================
 3  
 4  ## bitcoinconsensus
 5  ***This library is deprecated and will be removed in v28***
 6  
 7  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.
 8  
 9  ### API
10  
11  The interface is defined in the C header `bitcoinconsensus.h` located in `src/script/bitcoinconsensus.h`.
12  
13  #### Version
14  
15  `bitcoinconsensus_version` returns an `unsigned int` with the API version *(currently `2`)*.
16  
17  #### Script Validation
18  
19  `bitcoinconsensus_verify_script`, `bitcoinconsensus_verify_script_with_amount` and `bitcoinconsensus_verify_script_with_spent_outputs` return an `int` with the status of the verification. It will be `1` if the input script correctly spends the previous output `scriptPubKey`.
20  
21  ##### Parameters
22  ###### bitcoinconsensus_verify_script
23  - `const unsigned char *scriptPubKey` - The previous output script that encumbers spending.
24  - `unsigned int scriptPubKeyLen` - The number of bytes for the `scriptPubKey`.
25  - `const unsigned char *txTo` - The transaction with the input that is spending the previous output.
26  - `unsigned int txToLen` - The number of bytes for the `txTo`.
27  - `unsigned int nIn` - The index of the input in `txTo` that spends the `scriptPubKey`.
28  - `unsigned int flags` - The script validation flags *(see below)*.
29  - `bitcoinconsensus_error* err` - Will have the error/success code for the operation *(see below)*.
30  
31  ###### bitcoinconsensus_verify_script_with_amount
32  - `const unsigned char *scriptPubKey` - The previous output script that encumbers spending.
33  - `unsigned int scriptPubKeyLen` - The number of bytes for the `scriptPubKey`.
34  - `int64_t amount` - The amount spent in the input
35  - `const unsigned char *txTo` - The transaction with the input that is spending the previous output.
36  - `unsigned int txToLen` - The number of bytes for the `txTo`.
37  - `unsigned int nIn` - The index of the input in `txTo` that spends the `scriptPubKey`.
38  - `unsigned int flags` - The script validation flags *(see below)*.
39  - `bitcoinconsensus_error* err` - Will have the error/success code for the operation *(see below)*.
40  
41  ###### bitcoinconsensus_verify_script_with_spent_outputs
42  - `const unsigned char *scriptPubKey` - The previous output script that encumbers spending.
43  - `unsigned int scriptPubKeyLen` - The number of bytes for the `scriptPubKey`.
44  - `int64_t amount` - The amount spent in the input
45  - `const unsigned char *txTo` - The transaction with the input that is spending the previous output.
46  - `unsigned int txToLen` - The number of bytes for the `txTo`.
47  - `UTXO *spentOutputs` - Previous outputs spent in the transaction. `UTXO` is a struct composed by `const unsigned char *scriptPubKey`, `unsigned int scriptPubKeySize` (the number of bytes for the `scriptPubKey`) and `unsigned int value`.
48  - `unsigned int spentOutputsLen` - The number of bytes for the `spentOutputs`.
49  - `unsigned int nIn` - The index of the input in `txTo` that spends the `scriptPubKey`.
50  - `unsigned int flags` - The script validation flags *(see below)*.
51  - `bitcoinconsensus_error* err` - Will have the error/success code for the operation *(see below)*.
52  
53  ##### Script Flags
54  - `bitcoinconsensus_SCRIPT_FLAGS_VERIFY_NONE`
55  - `bitcoinconsensus_SCRIPT_FLAGS_VERIFY_P2SH` - Evaluate P2SH ([BIP16](https://github.com/bitcoin/bips/blob/master/bip-0016.mediawiki)) subscripts
56  - `bitcoinconsensus_SCRIPT_FLAGS_VERIFY_DERSIG` - Enforce strict DER ([BIP66](https://github.com/bitcoin/bips/blob/master/bip-0066.mediawiki)) compliance
57  - `bitcoinconsensus_SCRIPT_FLAGS_VERIFY_NULLDUMMY` - Enforce NULLDUMMY ([BIP147](https://github.com/bitcoin/bips/blob/master/bip-0147.mediawiki))
58  - `bitcoinconsensus_SCRIPT_FLAGS_VERIFY_CHECKLOCKTIMEVERIFY` - Enable CHECKLOCKTIMEVERIFY ([BIP65](https://github.com/bitcoin/bips/blob/master/bip-0065.mediawiki))
59  - `bitcoinconsensus_SCRIPT_FLAGS_VERIFY_CHECKSEQUENCEVERIFY` - Enable CHECKSEQUENCEVERIFY ([BIP112](https://github.com/bitcoin/bips/blob/master/bip-0112.mediawiki))
60  - `bitcoinconsensus_SCRIPT_FLAGS_VERIFY_WITNESS` - Enable WITNESS ([BIP141](https://github.com/bitcoin/bips/blob/master/bip-0141.mediawiki))
61  - `bitcoinconsensus_SCRIPT_FLAGS_VERIFY_TAPROOT` - Enable TAPROOT ([BIP340](https://github.com/bitcoin/bips/blob/master/bip-0340.mediawiki), [BIP341](https://github.com/bitcoin/bips/blob/master/bip-0341.mediawiki), [BIP342](https://github.com/bitcoin/bips/blob/master/bip-0342.mediawiki))
62  
63  ##### Errors
64  - `bitcoinconsensus_ERR_OK` - No errors with input parameters *(see the return value of `bitcoinconsensus_verify_script` for the verification status)*
65  - `bitcoinconsensus_ERR_TX_INDEX` - An invalid index for `txTo`
66  - `bitcoinconsensus_ERR_TX_SIZE_MISMATCH` - `txToLen` did not match with the size of `txTo`
67  - `bitcoinconsensus_ERR_DESERIALIZE` - An error deserializing `txTo`
68  - `bitcoinconsensus_ERR_AMOUNT_REQUIRED` - Input amount is required if WITNESS is used
69  - `bitcoinconsensus_ERR_INVALID_FLAGS` - Script verification `flags` are invalid (i.e. not part of the libconsensus interface)
70  - `bitcoinconsensus_ERR_SPENT_OUTPUTS_REQUIRED` - Spent outputs are required if TAPROOT is used
71  - `bitcoinconsensus_ERR_SPENT_OUTPUTS_MISMATCH` - Spent outputs size doesn't match tx inputs size
72  
73  ### Example Implementations
74  - [NBitcoin](https://github.com/MetacoSA/NBitcoin/blob/5e1055cd7c4186dee4227c344af8892aea54faec/NBitcoin/Script.cs#L979-#L1031) (.NET Bindings)
75  - [node-libbitcoinconsensus](https://github.com/bitpay/node-libbitcoinconsensus) (Node.js Bindings)
76  - [java-libbitcoinconsensus](https://github.com/dexX7/java-libbitcoinconsensus) (Java Bindings)
77  - [bitcoinconsensus-php](https://github.com/Bit-Wasp/bitcoinconsensus-php) (PHP Bindings)
78  - [rust-bitcoinconsensus](https://github.com/rust-bitcoin/rust-bitcoinconsensus) (Rust Bindings)