Line data    Source code

       1              : // Copyright (c) 2017, 2021 Pieter Wuille
       2              : // Copyright (c) 2021-present The Bitcoin Core developers
       3              : // Distributed under the MIT software license, see the accompanying
       4              : // file COPYING or http://www.opensource.org/licenses/mit-license.php.
       5              : 
       6              : // Bech32 and Bech32m are string encoding formats used in newer
       7              : // address types. The outputs consist of a human-readable part
       8              : // (alphanumeric), a separator character (1), and a base32 data
       9              : // section, the last 6 characters of which are a checksum. The
      10              : // module is namespaced under bech32 for historical reasons.
      11              : //
      12              : // For more information, see BIP 173 and BIP 350.
      13              : 
      14              : #ifndef BITCOIN_BECH32_H
      15              : #define BITCOIN_BECH32_H
      16              : 
      17              : #include <cstddef>
      18              : #include <cstdint>
      19              : #include <string>
      20              : #include <utility>
      21              : #include <vector>
      22              : 
      23              : namespace bech32
      24              : {
      25              : 
      26              : static constexpr size_t CHECKSUM_SIZE = 6;
      27              : static constexpr char SEPARATOR = '1';
      28              : 
      29              : enum class Encoding {
      30              :     INVALID, //!< Failed decoding
      31              : 
      32              :     BECH32,  //!< Bech32 encoding as defined in BIP173
      33              :     BECH32M, //!< Bech32m encoding as defined in BIP350
      34              : };
      35              : 
      36              : /** Character limits for Bech32(m) encoded strings. Character limits are how we provide error location guarantees.
      37              :  *  These values should never exceed 2^31 - 1 (max value for a 32-bit int), since there are places where we may need to
      38              :  *  convert the CharLimit::VALUE to an int. In practice, this should never happen since this CharLimit applies to an address encoding
      39              :  *  and we would never encode an address with such a massive value */
      40              : enum CharLimit : size_t {
      41              :     BECH32 = 90,            //!< BIP173/350 imposed character limit for Bech32(m) encoded addresses. This guarantees finding up to 4 errors.
      42              : };
      43              : 
      44              : /** Encode a Bech32 or Bech32m string. If hrp contains uppercase characters, this will cause an
      45              :  *  assertion error. Encoding must be one of BECH32 or BECH32M. */
      46              : std::string Encode(Encoding encoding, const std::string& hrp, const std::vector<uint8_t>& values);
      47              : 
      48          174 : struct DecodeResult
      49              : {
      50              :     Encoding encoding;         //!< What encoding was detected in the result; Encoding::INVALID if failed.
      51              :     std::string hrp;           //!< The human readable part
      52              :     std::vector<uint8_t> data; //!< The payload (excluding checksum)
      53              : 
      54           42 :     DecodeResult() : encoding(Encoding::INVALID) {}
      55          132 :     DecodeResult(Encoding enc, std::string&& h, std::vector<uint8_t>&& d) : encoding(enc), hrp(std::move(h)), data(std::move(d)) {}
      56              : };
      57              : 
      58              : /** Decode a Bech32 or Bech32m string. */
      59              : DecodeResult Decode(const std::string& str, CharLimit limit = CharLimit::BECH32);
      60              : 
      61              : /** Return the positions of errors in a Bech32 string. */
      62              : std::pair<std::string, std::vector<int>> LocateErrors(const std::string& str, CharLimit limit = CharLimit::BECH32);
      63              : 
      64              : } // namespace bech32
      65              : 
      66              : #endif // BITCOIN_BECH32_H