1  // Copyright (c) 2014-present The Bitcoin Core developers
  2  // Distributed under the MIT software license, see the accompanying
  3  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  4  
  5  #include <key_io.h>
  6  
  7  #include <base58.h>
  8  #include <bech32.h>
  9  #include <script/interpreter.h>
 10  #include <script/solver.h>
 11  #include <tinyformat.h>
 12  #include <util/overflow.h>
 13  #include <util/strencodings.h>
 14  
 15  #include <algorithm>
 16  #include <cassert>
 17  #include <cstring>
 18  
 19  /// Maximum witness length for Bech32 addresses.
 20  static constexpr std::size_t BECH32_WITNESS_PROG_MAX_LEN = 40;
 21  
 22  namespace {
 23  class DestinationEncoder
 24  {
 25  private:
 26      const CChainParams& m_params;
 27  
 28  public:
 29      explicit DestinationEncoder(const CChainParams& params) : m_params(params) {}
 30  
 31      std::string operator()(const PKHash& id) const
 32      {
 33          std::vector<unsigned char> data = m_params.Base58Prefix(CChainParams::PUBKEY_ADDRESS);
 34          data.insert(data.end(), id.begin(), id.end());
 35          return EncodeBase58Check(data);
 36      }
 37  
 38      std::string operator()(const ScriptHash& id) const
 39      {
 40          std::vector<unsigned char> data = m_params.Base58Prefix(CChainParams::SCRIPT_ADDRESS);
 41          data.insert(data.end(), id.begin(), id.end());
 42          return EncodeBase58Check(data);
 43      }
 44  
 45      std::string operator()(const WitnessV0KeyHash& id) const
 46      {
 47          std::vector<unsigned char> data = {0};
 48          data.reserve(33);
 49          ConvertBits<8, 5, true>([&](unsigned char c) { data.push_back(c); }, id.begin(), id.end());
 50          return bech32::Encode(bech32::Encoding::BECH32, m_params.Bech32HRP(), data);
 51      }
 52  
 53      std::string operator()(const WitnessV0ScriptHash& id) const
 54      {
 55          std::vector<unsigned char> data = {0};
 56          data.reserve(53);
 57          ConvertBits<8, 5, true>([&](unsigned char c) { data.push_back(c); }, id.begin(), id.end());
 58          return bech32::Encode(bech32::Encoding::BECH32, m_params.Bech32HRP(), data);
 59      }
 60  
 61      std::string operator()(const WitnessV1Taproot& tap) const
 62      {
 63          std::vector<unsigned char> data = {1};
 64          data.reserve(53);
 65          ConvertBits<8, 5, true>([&](unsigned char c) { data.push_back(c); }, tap.begin(), tap.end());
 66          return bech32::Encode(bech32::Encoding::BECH32M, m_params.Bech32HRP(), data);
 67      }
 68  
 69      std::string operator()(const WitnessUnknown& id) const
 70      {
 71          const std::vector<unsigned char>& program = id.GetWitnessProgram();
 72          if (id.GetWitnessVersion() < 1 || id.GetWitnessVersion() > 16 || program.size() < 2 || program.size() > 40) {
 73              return {};
 74          }
 75          std::vector<unsigned char> data = {(unsigned char)id.GetWitnessVersion()};
 76          data.reserve(1 + CeilDiv(program.size() * 8, 5u));
 77          ConvertBits<8, 5, true>([&](unsigned char c) { data.push_back(c); }, program.begin(), program.end());
 78          return bech32::Encode(bech32::Encoding::BECH32M, m_params.Bech32HRP(), data);
 79      }
 80  
 81      std::string operator()(const CNoDestination& no) const { return {}; }
 82      std::string operator()(const PubKeyDestination& pk) const { return {}; }
 83  };
 84  
 85  CTxDestination DecodeDestination(const std::string& str, const CChainParams& params, std::string& error_str, std::vector<int>* error_locations)
 86  {
 87      std::vector<unsigned char> data;
 88      uint160 hash;
 89      error_str = "";
 90  
 91      // Note this will be false if it is a valid Bech32 address for a different network
 92      bool is_bech32 = (ToLower(str.substr(0, params.Bech32HRP().size())) == params.Bech32HRP());
 93  
 94      if (!is_bech32 && DecodeBase58Check(str, data, 21)) {
 95          // base58-encoded Bitcoin addresses.
 96          // Public-key-hash-addresses have version 0 (or 111 testnet).
 97          // The data vector contains RIPEMD160(SHA256(pubkey)), where pubkey is the serialized public key.
 98          const std::vector<unsigned char>& pubkey_prefix = params.Base58Prefix(CChainParams::PUBKEY_ADDRESS);
 99          if (data.size() == hash.size() + pubkey_prefix.size() && std::equal(pubkey_prefix.begin(), pubkey_prefix.end(), data.begin())) {
100              std::copy(data.begin() + pubkey_prefix.size(), data.end(), hash.begin());
101              return PKHash(hash);
102          }
103          // Script-hash-addresses have version 5 (or 196 testnet).
104          // The data vector contains RIPEMD160(SHA256(cscript)), where cscript is the serialized redemption script.
105          const std::vector<unsigned char>& script_prefix = params.Base58Prefix(CChainParams::SCRIPT_ADDRESS);
106          if (data.size() == hash.size() + script_prefix.size() && std::equal(script_prefix.begin(), script_prefix.end(), data.begin())) {
107              std::copy(data.begin() + script_prefix.size(), data.end(), hash.begin());
108              return ScriptHash(hash);
109          }
110  
111          // If the prefix of data matches either the script or pubkey prefix, the length must have been wrong
112          if ((data.size() >= script_prefix.size() &&
113                  std::equal(script_prefix.begin(), script_prefix.end(), data.begin())) ||
114              (data.size() >= pubkey_prefix.size() &&
115                  std::equal(pubkey_prefix.begin(), pubkey_prefix.end(), data.begin()))) {
116              error_str = "Invalid length for Base58 address (P2PKH or P2SH)";
117          } else {
118              error_str = "Invalid or unsupported Base58-encoded address.";
119          }
120          return CNoDestination();
121      } else if (!is_bech32) {
122          // Try Base58 decoding without the checksum, using a much larger max length
123          if (!DecodeBase58(str, data, 100)) {
124              error_str = "Invalid or unsupported Segwit (Bech32) or Base58 encoding.";
125          } else {
126              error_str = "Invalid checksum or length of Base58 address (P2PKH or P2SH)";
127          }
128          return CNoDestination();
129      }
130  
131      data.clear();
132      const auto dec = bech32::Decode(str);
133      if (dec.encoding == bech32::Encoding::BECH32 || dec.encoding == bech32::Encoding::BECH32M) {
134          if (dec.data.empty()) {
135              error_str = "Empty Bech32 data section";
136              return CNoDestination();
137          }
138          // Bech32 decoding
139          if (dec.hrp != params.Bech32HRP()) {
140              error_str = strprintf("Invalid or unsupported prefix for Segwit (Bech32) address (expected %s, got %s).", params.Bech32HRP(), dec.hrp);
141              return CNoDestination();
142          }
143          int version = dec.data[0]; // The first 5 bit symbol is the witness version (0-16)
144          if (version == 0 && dec.encoding != bech32::Encoding::BECH32) {
145              error_str = "Version 0 witness address must use Bech32 checksum";
146              return CNoDestination();
147          }
148          if (version != 0 && dec.encoding != bech32::Encoding::BECH32M) {
149              error_str = "Version 1+ witness address must use Bech32m checksum";
150              return CNoDestination();
151          }
152          // The rest of the symbols are converted witness program bytes.
153          data.reserve(((dec.data.size() - 1) * 5) / 8);
154          if (ConvertBits<5, 8, false>([&](unsigned char c) { data.push_back(c); }, dec.data.begin() + 1, dec.data.end())) {
155  
156              std::string_view byte_str{data.size() == 1 ? "byte" : "bytes"};
157  
158              if (version == 0) {
159                  {
160                      WitnessV0KeyHash keyid;
161                      if (data.size() == keyid.size()) {
162                          std::copy(data.begin(), data.end(), keyid.begin());
163                          return keyid;
164                      }
165                  }
166                  {
167                      WitnessV0ScriptHash scriptid;
168                      if (data.size() == scriptid.size()) {
169                          std::copy(data.begin(), data.end(), scriptid.begin());
170                          return scriptid;
171                      }
172                  }
173  
174                  error_str = strprintf("Invalid Bech32 v0 address program size (%d %s), per BIP141", data.size(), byte_str);
175                  return CNoDestination();
176              }
177  
178              if (version == 1 && data.size() == WITNESS_V1_TAPROOT_SIZE) {
179                  static_assert(WITNESS_V1_TAPROOT_SIZE == WitnessV1Taproot::size());
180                  WitnessV1Taproot tap;
181                  std::copy(data.begin(), data.end(), tap.begin());
182                  return tap;
183              }
184  
185              if (CScript::IsPayToAnchor(version, data)) {
186                  return PayToAnchor();
187              }
188  
189              if (version > 16) {
190                  error_str = "Invalid Bech32 address witness version";
191                  return CNoDestination();
192              }
193  
194              if (data.size() < 2 || data.size() > BECH32_WITNESS_PROG_MAX_LEN) {
195                  error_str = strprintf("Invalid Bech32 address program size (%d %s)", data.size(), byte_str);
196                  return CNoDestination();
197              }
198  
199              return WitnessUnknown{version, data};
200          } else {
201              error_str = strprintf("Invalid padding in Bech32 data section");
202              return CNoDestination();
203          }
204      }
205  
206      // Perform Bech32 error location
207      auto res = bech32::LocateErrors(str);
208      error_str = res.first;
209      if (error_locations) *error_locations = std::move(res.second);
210      return CNoDestination();
211  }
212  } // namespace
213  
214  CKey DecodeSecret(const std::string& str)
215  {
216      CKey key;
217      std::vector<unsigned char> data;
218      if (DecodeBase58Check(str, data, 34)) {
219          const std::vector<unsigned char>& privkey_prefix = Params().Base58Prefix(CChainParams::SECRET_KEY);
220          if ((data.size() == 32 + privkey_prefix.size() || (data.size() == 33 + privkey_prefix.size() && data.back() == 1)) &&
221              std::equal(privkey_prefix.begin(), privkey_prefix.end(), data.begin())) {
222              bool compressed = data.size() == 33 + privkey_prefix.size();
223              key.Set(data.begin() + privkey_prefix.size(), data.begin() + privkey_prefix.size() + 32, compressed);
224          }
225      }
226      if (!data.empty()) {
227          memory_cleanse(data.data(), data.size());
228      }
229      return key;
230  }
231  
232  std::string EncodeSecret(const CKey& key)
233  {
234      assert(key.IsValid());
235      std::vector<unsigned char> data = Params().Base58Prefix(CChainParams::SECRET_KEY);
236      data.insert(data.end(), UCharCast(key.begin()), UCharCast(key.end()));
237      if (key.IsCompressed()) {
238          data.push_back(1);
239      }
240      std::string ret = EncodeBase58Check(data);
241      memory_cleanse(data.data(), data.size());
242      return ret;
243  }
244  
245  CExtPubKey DecodeExtPubKey(const std::string& str)
246  {
247      CExtPubKey key;
248      std::vector<unsigned char> data;
249      if (DecodeBase58Check(str, data, 78)) {
250          const std::vector<unsigned char>& prefix = Params().Base58Prefix(CChainParams::EXT_PUBLIC_KEY);
251          if (data.size() == BIP32_EXTKEY_SIZE + prefix.size() && std::equal(prefix.begin(), prefix.end(), data.begin())) {
252              key.Decode(data.data() + prefix.size());
253          }
254      }
255      return key;
256  }
257  
258  std::string EncodeExtPubKey(const CExtPubKey& key)
259  {
260      std::vector<unsigned char> data = Params().Base58Prefix(CChainParams::EXT_PUBLIC_KEY);
261      size_t size = data.size();
262      data.resize(size + BIP32_EXTKEY_SIZE);
263      key.Encode(data.data() + size);
264      std::string ret = EncodeBase58Check(data);
265      return ret;
266  }
267  
268  CExtKey DecodeExtKey(const std::string& str)
269  {
270      CExtKey key;
271      std::vector<unsigned char> data;
272      if (DecodeBase58Check(str, data, 78)) {
273          const std::vector<unsigned char>& prefix = Params().Base58Prefix(CChainParams::EXT_SECRET_KEY);
274          if (data.size() == BIP32_EXTKEY_SIZE + prefix.size() && std::equal(prefix.begin(), prefix.end(), data.begin())) {
275              key.Decode(data.data() + prefix.size());
276          }
277      }
278      if (!data.empty()) {
279          memory_cleanse(data.data(), data.size());
280      }
281      return key;
282  }
283  
284  std::string EncodeExtKey(const CExtKey& key)
285  {
286      std::vector<unsigned char> data = Params().Base58Prefix(CChainParams::EXT_SECRET_KEY);
287      size_t size = data.size();
288      data.resize(size + BIP32_EXTKEY_SIZE);
289      key.Encode(data.data() + size);
290      std::string ret = EncodeBase58Check(data);
291      memory_cleanse(data.data(), data.size());
292      return ret;
293  }
294  
295  std::string EncodeDestination(const CTxDestination& dest)
296  {
297      return std::visit(DestinationEncoder(Params()), dest);
298  }
299  
300  CTxDestination DecodeDestination(const std::string& str, std::string& error_msg, std::vector<int>* error_locations)
301  {
302      return DecodeDestination(str, Params(), error_msg, error_locations);
303  }
304  
305  CTxDestination DecodeDestination(const std::string& str)
306  {
307      std::string error_msg;
308      return DecodeDestination(str, error_msg);
309  }
310  
311  bool IsValidDestinationString(const std::string& str, const CChainParams& params)
312  {
313      std::string error_msg;
314      return IsValidDestination(DecodeDestination(str, params, error_msg, nullptr));
315  }
316  
317  bool IsValidDestinationString(const std::string& str)
318  {
319      return IsValidDestinationString(str, Params());
320  }