1  // Copyright (c) 2014-2021 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/strencodings.h>
 13  
 14  #include <algorithm>
 15  #include <assert.h>
 16  #include <string.h>
 17  
 18  /// Maximum witness length for Bech32 addresses.
 19  static constexpr std::size_t BECH32_WITNESS_PROG_MAX_LEN = 40;
 20  
 21  namespace {
 22  class DestinationEncoder
 23  {
 24  private:
 25      const CChainParams& m_params;
 26  
 27  public:
 28      explicit DestinationEncoder(const CChainParams& params) : m_params(params) {}
 29  
 30      std::string operator()(const PKHash& id) const
 31      {
 32          std::vector<unsigned char> data = m_params.Base58Prefix(CChainParams::PUBKEY_ADDRESS);
 33          data.insert(data.end(), id.begin(), id.end());
 34          return EncodeBase58Check(data);
 35      }
 36  
 37      std::string operator()(const ScriptHash& id) const
 38      {
 39          std::vector<unsigned char> data = m_params.Base58Prefix(CChainParams::SCRIPT_ADDRESS);
 40          data.insert(data.end(), id.begin(), id.end());
 41          return EncodeBase58Check(data);
 42      }
 43  
 44      std::string operator()(const WitnessV0KeyHash& id) const
 45      {
 46          std::vector<unsigned char> data = {0};
 47          data.reserve(33);
 48          ConvertBits<8, 5, true>([&](unsigned char c) { data.push_back(c); }, id.begin(), id.end());
 49          return bech32::Encode(bech32::Encoding::BECH32, m_params.Bech32HRP(), data);
 50      }
 51  
 52      std::string operator()(const WitnessV0ScriptHash& id) const
 53      {
 54          std::vector<unsigned char> data = {0};
 55          data.reserve(53);
 56          ConvertBits<8, 5, true>([&](unsigned char c) { data.push_back(c); }, id.begin(), id.end());
 57          return bech32::Encode(bech32::Encoding::BECH32, m_params.Bech32HRP(), data);
 58      }
 59  
 60      std::string operator()(const WitnessV1Taproot& tap) const
 61      {
 62          std::vector<unsigned char> data = {1};
 63          data.reserve(53);
 64          ConvertBits<8, 5, true>([&](unsigned char c) { data.push_back(c); }, tap.begin(), tap.end());
 65          return bech32::Encode(bech32::Encoding::BECH32M, m_params.Bech32HRP(), data);
 66      }
 67  
 68      std::string operator()(const WitnessUnknown& id) const
 69      {
 70          const std::vector<unsigned char>& program = id.GetWitnessProgram();
 71          if (id.GetWitnessVersion() < 1 || id.GetWitnessVersion() > 16 || program.size() < 2 || program.size() > 40) {
 72              return {};
 73          }
 74          std::vector<unsigned char> data = {(unsigned char)id.GetWitnessVersion()};
 75          data.reserve(1 + (program.size() * 8 + 4) / 5);
 76          ConvertBits<8, 5, true>([&](unsigned char c) { data.push_back(c); }, program.begin(), program.end());
 77          return bech32::Encode(bech32::Encoding::BECH32M, m_params.Bech32HRP(), data);
 78      }
 79  
 80      std::string operator()(const CNoDestination& no) const { return {}; }
 81      std::string operator()(const PubKeyDestination& pk) const { return {}; }
 82  };
 83  
 84  CTxDestination DecodeDestination(const std::string& str, const CChainParams& params, std::string& error_str, std::vector<int>* error_locations)
 85  {
 86      std::vector<unsigned char> data;
 87      uint160 hash;
 88      error_str = "";
 89  
 90      // Note this will be false if it is a valid Bech32 address for a different network
 91      bool is_bech32 = (ToLower(str.substr(0, params.Bech32HRP().size())) == params.Bech32HRP());
 92  
 93      if (!is_bech32 && DecodeBase58Check(str, data, 21)) {
 94          // base58-encoded Bitcoin addresses.
 95          // Public-key-hash-addresses have version 0 (or 111 testnet).
 96          // The data vector contains RIPEMD160(SHA256(pubkey)), where pubkey is the serialized public key.
 97          const std::vector<unsigned char>& pubkey_prefix = params.Base58Prefix(CChainParams::PUBKEY_ADDRESS);
 98          if (data.size() == hash.size() + pubkey_prefix.size() && std::equal(pubkey_prefix.begin(), pubkey_prefix.end(), data.begin())) {
 99              std::copy(data.begin() + pubkey_prefix.size(), data.end(), hash.begin());
100              return PKHash(hash);
101          }
102          // Script-hash-addresses have version 5 (or 196 testnet).
103          // The data vector contains RIPEMD160(SHA256(cscript)), where cscript is the serialized redemption script.
104          const std::vector<unsigned char>& script_prefix = params.Base58Prefix(CChainParams::SCRIPT_ADDRESS);
105          if (data.size() == hash.size() + script_prefix.size() && std::equal(script_prefix.begin(), script_prefix.end(), data.begin())) {
106              std::copy(data.begin() + script_prefix.size(), data.end(), hash.begin());
107              return ScriptHash(hash);
108          }
109  
110          // If the prefix of data matches either the script or pubkey prefix, the length must have been wrong
111          if ((data.size() >= script_prefix.size() &&
112                  std::equal(script_prefix.begin(), script_prefix.end(), data.begin())) ||
113              (data.size() >= pubkey_prefix.size() &&
114                  std::equal(pubkey_prefix.begin(), pubkey_prefix.end(), data.begin()))) {
115              error_str = "Invalid length for Base58 address (P2PKH or P2SH)";
116          } else {
117              error_str = "Invalid or unsupported Base58-encoded address.";
118          }
119          return CNoDestination();
120      } else if (!is_bech32) {
121          // Try Base58 decoding without the checksum, using a much larger max length
122          if (!DecodeBase58(str, data, 100)) {
123              error_str = "Invalid or unsupported Segwit (Bech32) or Base58 encoding.";
124          } else {
125              error_str = "Invalid checksum or length of Base58 address (P2PKH or P2SH)";
126          }
127          return CNoDestination();
128      }
129  
130      data.clear();
131      const auto dec = bech32::Decode(str);
132      if (dec.encoding == bech32::Encoding::BECH32 || dec.encoding == bech32::Encoding::BECH32M) {
133          if (dec.data.empty()) {
134              error_str = "Empty Bech32 data section";
135              return CNoDestination();
136          }
137          // Bech32 decoding
138          if (dec.hrp != params.Bech32HRP()) {
139              error_str = strprintf("Invalid or unsupported prefix for Segwit (Bech32) address (expected %s, got %s).", params.Bech32HRP(), dec.hrp);
140              return CNoDestination();
141          }
142          int version = dec.data[0]; // The first 5 bit symbol is the witness version (0-16)
143          if (version == 0 && dec.encoding != bech32::Encoding::BECH32) {
144              error_str = "Version 0 witness address must use Bech32 checksum";
145              return CNoDestination();
146          }
147          if (version != 0 && dec.encoding != bech32::Encoding::BECH32M) {
148              error_str = "Version 1+ witness address must use Bech32m checksum";
149              return CNoDestination();
150          }
151          // The rest of the symbols are converted witness program bytes.
152          data.reserve(((dec.data.size() - 1) * 5) / 8);
153          if (ConvertBits<5, 8, false>([&](unsigned char c) { data.push_back(c); }, dec.data.begin() + 1, dec.data.end())) {
154  
155              std::string_view byte_str{data.size() == 1 ? "byte" : "bytes"};
156  
157              if (version == 0) {
158                  {
159                      WitnessV0KeyHash keyid;
160                      if (data.size() == keyid.size()) {
161                          std::copy(data.begin(), data.end(), keyid.begin());
162                          return keyid;
163                      }
164                  }
165                  {
166                      WitnessV0ScriptHash scriptid;
167                      if (data.size() == scriptid.size()) {
168                          std::copy(data.begin(), data.end(), scriptid.begin());
169                          return scriptid;
170                      }
171                  }
172  
173                  error_str = strprintf("Invalid Bech32 v0 address program size (%d %s), per BIP141", data.size(), byte_str);
174                  return CNoDestination();
175              }
176  
177              if (version == 1 && data.size() == WITNESS_V1_TAPROOT_SIZE) {
178                  static_assert(WITNESS_V1_TAPROOT_SIZE == WitnessV1Taproot::size());
179                  WitnessV1Taproot tap;
180                  std::copy(data.begin(), data.end(), tap.begin());
181                  return tap;
182              }
183  
184              if (version > 16) {
185                  error_str = "Invalid Bech32 address witness version";
186                  return CNoDestination();
187              }
188  
189              if (data.size() < 2 || data.size() > BECH32_WITNESS_PROG_MAX_LEN) {
190                  error_str = strprintf("Invalid Bech32 address program size (%d %s)", data.size(), byte_str);
191                  return CNoDestination();
192              }
193  
194              return WitnessUnknown{version, data};
195          } else {
196              error_str = strprintf("Invalid padding in Bech32 data section");
197              return CNoDestination();
198          }
199      }
200  
201      // Perform Bech32 error location
202      auto res = bech32::LocateErrors(str);
203      error_str = res.first;
204      if (error_locations) *error_locations = std::move(res.second);
205      return CNoDestination();
206  }
207  } // namespace
208  
209  CKey DecodeSecret(const std::string& str)
210  {
211      CKey key;
212      std::vector<unsigned char> data;
213      if (DecodeBase58Check(str, data, 34)) {
214          const std::vector<unsigned char>& privkey_prefix = Params().Base58Prefix(CChainParams::SECRET_KEY);
215          if ((data.size() == 32 + privkey_prefix.size() || (data.size() == 33 + privkey_prefix.size() && data.back() == 1)) &&
216              std::equal(privkey_prefix.begin(), privkey_prefix.end(), data.begin())) {
217              bool compressed = data.size() == 33 + privkey_prefix.size();
218              key.Set(data.begin() + privkey_prefix.size(), data.begin() + privkey_prefix.size() + 32, compressed);
219          }
220      }
221      if (!data.empty()) {
222          memory_cleanse(data.data(), data.size());
223      }
224      return key;
225  }
226  
227  std::string EncodeSecret(const CKey& key)
228  {
229      assert(key.IsValid());
230      std::vector<unsigned char> data = Params().Base58Prefix(CChainParams::SECRET_KEY);
231      data.insert(data.end(), UCharCast(key.begin()), UCharCast(key.end()));
232      if (key.IsCompressed()) {
233          data.push_back(1);
234      }
235      std::string ret = EncodeBase58Check(data);
236      memory_cleanse(data.data(), data.size());
237      return ret;
238  }
239  
240  CExtPubKey DecodeExtPubKey(const std::string& str)
241  {
242      CExtPubKey key;
243      std::vector<unsigned char> data;
244      if (DecodeBase58Check(str, data, 78)) {
245          const std::vector<unsigned char>& prefix = Params().Base58Prefix(CChainParams::EXT_PUBLIC_KEY);
246          if (data.size() == BIP32_EXTKEY_SIZE + prefix.size() && std::equal(prefix.begin(), prefix.end(), data.begin())) {
247              key.Decode(data.data() + prefix.size());
248          }
249      }
250      return key;
251  }
252  
253  std::string EncodeExtPubKey(const CExtPubKey& key)
254  {
255      std::vector<unsigned char> data = Params().Base58Prefix(CChainParams::EXT_PUBLIC_KEY);
256      size_t size = data.size();
257      data.resize(size + BIP32_EXTKEY_SIZE);
258      key.Encode(data.data() + size);
259      std::string ret = EncodeBase58Check(data);
260      return ret;
261  }
262  
263  CExtKey DecodeExtKey(const std::string& str)
264  {
265      CExtKey key;
266      std::vector<unsigned char> data;
267      if (DecodeBase58Check(str, data, 78)) {
268          const std::vector<unsigned char>& prefix = Params().Base58Prefix(CChainParams::EXT_SECRET_KEY);
269          if (data.size() == BIP32_EXTKEY_SIZE + prefix.size() && std::equal(prefix.begin(), prefix.end(), data.begin())) {
270              key.Decode(data.data() + prefix.size());
271          }
272      }
273      return key;
274  }
275  
276  std::string EncodeExtKey(const CExtKey& key)
277  {
278      std::vector<unsigned char> data = Params().Base58Prefix(CChainParams::EXT_SECRET_KEY);
279      size_t size = data.size();
280      data.resize(size + BIP32_EXTKEY_SIZE);
281      key.Encode(data.data() + size);
282      std::string ret = EncodeBase58Check(data);
283      memory_cleanse(data.data(), data.size());
284      return ret;
285  }
286  
287  std::string EncodeDestination(const CTxDestination& dest)
288  {
289      return std::visit(DestinationEncoder(Params()), dest);
290  }
291  
292  CTxDestination DecodeDestination(const std::string& str, std::string& error_msg, std::vector<int>* error_locations)
293  {
294      return DecodeDestination(str, Params(), error_msg, error_locations);
295  }
296  
297  CTxDestination DecodeDestination(const std::string& str)
298  {
299      std::string error_msg;
300      return DecodeDestination(str, error_msg);
301  }
302  
303  bool IsValidDestinationString(const std::string& str, const CChainParams& params)
304  {
305      std::string error_msg;
306      return IsValidDestination(DecodeDestination(str, params, error_msg, nullptr));
307  }
308  
309  bool IsValidDestinationString(const std::string& str)
310  {
311      return IsValidDestinationString(str, Params());
312  }