// Copyright (c) 2014-2022 The Bitcoin Core developers // Distributed under the MIT software license, see the accompanying // file COPYING or http://www.opensource.org/licenses/mit-license.php. #include <base58.h> #include <hash.h> #include <uint256.h> #include <util/strencodings.h> #include <util/string.h> #include <assert.h> #include <string.h> #include <limits> /** All alphanumeric characters except for "0", "I", "O", and "l" */ static const char* pszBase58 = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"; static const int8_t mapBase58[256] = { -1,-1,-1,-1,-1,-1,-1,-1, -1,-1,-1,-1,-1,-1,-1,-1, -1,-1,-1,-1,-1,-1,-1,-1, -1,-1,-1,-1,-1,-1,-1,-1, -1,-1,-1,-1,-1,-1,-1,-1, -1,-1,-1,-1,-1,-1,-1,-1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8,-1,-1,-1,-1,-1,-1, -1, 9,10,11,12,13,14,15, 16,-1,17,18,19,20,21,-1, 22,23,24,25,26,27,28,29, 30,31,32,-1,-1,-1,-1,-1, -1,33,34,35,36,37,38,39, 40,41,42,43,-1,44,45,46, 47,48,49,50,51,52,53,54, 55,56,57,-1,-1,-1,-1,-1, -1,-1,-1,-1,-1,-1,-1,-1, -1,-1,-1,-1,-1,-1,-1,-1, -1,-1,-1,-1,-1,-1,-1,-1, -1,-1,-1,-1,-1,-1,-1,-1, -1,-1,-1,-1,-1,-1,-1,-1, -1,-1,-1,-1,-1,-1,-1,-1, -1,-1,-1,-1,-1,-1,-1,-1, -1,-1,-1,-1,-1,-1,-1,-1, -1,-1,-1,-1,-1,-1,-1,-1, -1,-1,-1,-1,-1,-1,-1,-1, -1,-1,-1,-1,-1,-1,-1,-1, -1,-1,-1,-1,-1,-1,-1,-1, -1,-1,-1,-1,-1,-1,-1,-1, -1,-1,-1,-1,-1,-1,-1,-1, -1,-1,-1,-1,-1,-1,-1,-1, -1,-1,-1,-1,-1,-1,-1,-1, }; [[nodiscard]] static bool DecodeBase58(const char* psz, std::vector<unsigned char>& vch, int max_ret_len) { // Skip leading spaces. while (*psz && IsSpace(*psz)) psz++; // Skip and count leading '1's. int zeroes = 0; int length = 0; while (*psz == '1') { zeroes++; if (zeroes > max_ret_len) return false; psz++; } // Allocate enough space in big-endian base256 representation. int size = strlen(psz) * 733 /1000 + 1; // log(58) / log(256), rounded up. std::vector<unsigned char> b256(size); // Process the characters. static_assert(std::size(mapBase58) == 256, "mapBase58.size() should be 256"); // guarantee not out of range while (*psz && !IsSpace(*psz)) { // Decode base58 character int carry = mapBase58[(uint8_t)*psz]; if (carry == -1) // Invalid b58 character return false; int i = 0; for (std::vector<unsigned char>::reverse_iterator it = b256.rbegin(); (carry != 0 || i < length) && (it != b256.rend()); ++it, ++i) { carry += 58 * (*it); *it = carry % 256; carry /= 256; } assert(carry == 0); length = i; if (length + zeroes > max_ret_len) return false; psz++; } // Skip trailing spaces. while (IsSpace(*psz)) psz++; if (*psz != 0) return false; // Skip leading zeroes in b256. std::vector<unsigned char>::iterator it = b256.begin() + (size - length); // Copy result into output vector. vch.reserve(zeroes + (b256.end() - it)); vch.assign(zeroes, 0x00); while (it != b256.end()) vch.push_back(*(it++)); return true; } std::string EncodeBase58(Span<const unsigned char> input) { // Skip & count leading zeroes. int zeroes = 0; int length = 0; while (input.size() > 0 && input[0] == 0) { input = input.subspan(1); zeroes++; } // Allocate enough space in big-endian base58 representation. int size = input.size() * 138 / 100 + 1; // log(256) / log(58), rounded up. std::vector<unsigned char> b58(size); // Process the bytes. while (input.size() > 0) { int carry = input[0]; int i = 0; // Apply "b58 = b58 * 256 + ch". for (std::vector<unsigned char>::reverse_iterator it = b58.rbegin(); (carry != 0 || i < length) && (it != b58.rend()); it++, i++) { carry += 256 * (*it); *it = carry % 58; carry /= 58; } assert(carry == 0); length = i; input = input.subspan(1); } // Skip leading zeroes in base58 result. std::vector<unsigned char>::iterator it = b58.begin() + (size - length); while (it != b58.end() && *it == 0) it++; // Translate the result into a string. std::string str; str.reserve(zeroes + (b58.end() - it)); str.assign(zeroes, '1'); while (it != b58.end()) str += pszBase58[*(it++)]; return str; } bool DecodeBase58(const std::string& str, std::vector<unsigned char>& vchRet, int max_ret_len) { if (!ContainsNoNUL(str)) { return false; } return DecodeBase58(str.c_str(), vchRet, max_ret_len); } std::string EncodeBase58Check(Span<const unsigned char> input) { // add 4-byte hash check to the end std::vector<unsigned char> vch(input.begin(), input.end()); uint256 hash = Hash(vch); vch.insert(vch.end(), (unsigned char*)&hash, (unsigned char*)&hash + 4); return EncodeBase58(vch); } [[nodiscard]] static bool DecodeBase58Check(const char* psz, std::vector<unsigned char>& vchRet, int max_ret_len) { if (!DecodeBase58(psz, vchRet, max_ret_len > std::numeric_limits<int>::max() - 4 ? std::numeric_limits<int>::max() : max_ret_len + 4) || (vchRet.size() < 4)) { vchRet.clear(); return false; } // re-calculate the checksum, ensure it matches the included 4-byte checksum uint256 hash = Hash(Span{vchRet}.first(vchRet.size() - 4)); if (memcmp(&hash, &vchRet[vchRet.size() - 4], 4) != 0) { vchRet.clear(); return false; } vchRet.resize(vchRet.size() - 4); return true; } bool DecodeBase58Check(const std::string& str, std::vector<unsigned char>& vchRet, int max_ret) { if (!ContainsNoNUL(str)) { return false; } return DecodeBase58Check(str.c_str(), vchRet, max_ret); }