src/base58.h

   1 // Copyright (c) 2009-2010 Satoshi Nakamoto
   2 // Copyright (c) 2009-2012 The Bitcoin Developers
   3 // Distributed under the MIT/X11 software license, see the accompanying
   4 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
   5
   6
   7 //
   8 // Why base-58 instead of standard base-64 encoding?
   9 // - Don't want 0OIl characters that look the same in some fonts and
  10 //      could be used to create visually identical looking account numbers.
  11 // - A string with non-alphanumeric characters is not as easily accepted as an account number.
  12 // - E-mail usually won't line-break if there's no punctuation to break at.
  13 // - Double-clicking selects the whole number as one word if it's all alphanumeric.
  14 //
  15 #ifndef BITCOIN_BASE58_H
  16 #define BITCOIN_BASE58_H
  17
  18 #include <string>
  19 #include <vector>
  20 #include "bignum.h"
  21 #include "key.h"
  22 #include "script.h"
  23
  24 static const char* pszBase58 = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
  25
  26 // Encode a byte sequence as a base58-encoded string
  27 inline std::string EncodeBase58(const unsigned char* pbegin, const unsigned char* pend)
  28 {
  29     CAutoBN_CTX pctx;
  30     CBigNum bn58 = 58;
  31     CBigNum bn0 = 0;
  32
  33     // Convert big endian data to little endian
  34     // Extra zero at the end make sure bignum will interpret as a positive number
  35     std::vector<unsigned char> vchTmp(pend-pbegin+1, 0);
  36     reverse_copy(pbegin, pend, vchTmp.begin());
  37
  38     // Convert little endian data to bignum
  39     CBigNum bn;
  40     bn.setvch(vchTmp);
  41
  42     // Convert bignum to std::string
  43     std::string str;
  44     // Expected size increase from base58 conversion is approximately 137%
  45     // use 138% to be safe
  46     str.reserve((pend - pbegin) * 138 / 100 + 1);
  47     CBigNum dv;
  48     CBigNum rem;
  49     while (bn > bn0)
  50     {
  51         if (!BN_div(&dv, &rem, &bn, &bn58, pctx))
  52             throw bignum_error("EncodeBase58 : BN_div failed");
  53         bn = dv;
  54         unsigned int c = rem.getulong();
  55         str += pszBase58[c];
  56     }
  57
  58     // Leading zeroes encoded as base58 zeros
  59     for (const unsigned char* p = pbegin; p < pend && *p == 0; p++)
  60         str += pszBase58[0];
  61
  62     // Convert little endian std::string to big endian
  63     reverse(str.begin(), str.end());
  64     return str;
  65 }
  66
  67 // Encode a byte vector as a base58-encoded string
  68 inline std::string EncodeBase58(const std::vector<unsigned char>& vch)
  69 {
  70     return EncodeBase58(&vch[0], &vch[0] + vch.size());
  71 }
  72
  73 // Decode a base58-encoded string psz into byte vector vchRet
  74 // returns true if decoding is successful
  75 inline bool DecodeBase58(const char* psz, std::vector<unsigned char>& vchRet)
  76 {
  77     CAutoBN_CTX pctx;
  78     vchRet.clear();
  79     CBigNum bn58 = 58;
  80     CBigNum bn = 0;
  81     CBigNum bnChar;
  82     while (isspace(*psz))
  83         psz++;
  84
  85     // Convert big endian string to bignum
  86     for (const char* p = psz; *p; p++)
  87     {
  88         const char* p1 = strchr(pszBase58, *p);
  89         if (p1 == NULL)
  90         {
  91             while (isspace(*p))
  92                 p++;
  93             if (*p != '\0')
  94                 return false;
  95             break;
  96         }
  97         bnChar.setulong(p1 - pszBase58);
  98         if (!BN_mul(&bn, &bn, &bn58, pctx))
  99             throw bignum_error("DecodeBase58 : BN_mul failed");
 100         bn += bnChar;
 101     }
 102
 103     // Get bignum as little endian data
 104     std::vector<unsigned char> vchTmp = bn.getvch();
 105
 106     // Trim off sign byte if present
 107     if (vchTmp.size() >= 2 && vchTmp.end()[-1] == 0 && vchTmp.end()[-2] >= 0x80)
 108         vchTmp.erase(vchTmp.end()-1);
 109
 110     // Restore leading zeros
 111     int nLeadingZeros = 0;
 112     for (const char* p = psz; *p == pszBase58[0]; p++)
 113         nLeadingZeros++;
 114     vchRet.assign(nLeadingZeros + vchTmp.size(), 0);
 115
 116     // Convert little endian data to big endian
 117     reverse_copy(vchTmp.begin(), vchTmp.end(), vchRet.end() - vchTmp.size());
 118     return true;
 119 }
 120
 121 // Decode a base58-encoded string str into byte vector vchRet
 122 // returns true if decoding is successful
 123 inline bool DecodeBase58(const std::string& str, std::vector<unsigned char>& vchRet)
 124 {
 125     return DecodeBase58(str.c_str(), vchRet);
 126 }
 127
 128
 129
 130
 131 // Encode a byte vector to a base58-encoded string, including checksum
 132 inline std::string EncodeBase58Check(const std::vector<unsigned char>& vchIn)
 133 {
 134     // add 4-byte hash check to the end
 135     std::vector<unsigned char> vch(vchIn);
 136     uint256 hash = Hash(vch.begin(), vch.end());
 137     vch.insert(vch.end(), (unsigned char*)&hash, (unsigned char*)&hash + 4);
 138     return EncodeBase58(vch);
 139 }
 140
 141 // Decode a base58-encoded string psz that includes a checksum, into byte vector vchRet
 142 // returns true if decoding is successful
 143 inline bool DecodeBase58Check(const char* psz, std::vector<unsigned char>& vchRet)
 144 {
 145     if (!DecodeBase58(psz, vchRet))
 146         return false;
 147     if (vchRet.size() < 4)
 148     {
 149         vchRet.clear();
 150         return false;
 151     }
 152     uint256 hash = Hash(vchRet.begin(), vchRet.end()-4);
 153     if (memcmp(&hash, &vchRet.end()[-4], 4) != 0)
 154     {
 155         vchRet.clear();
 156         return false;
 157     }
 158     vchRet.resize(vchRet.size()-4);
 159     return true;
 160 }
 161
 162 // Decode a base58-encoded string str that includes a checksum, into byte vector vchRet
 163 // returns true if decoding is successful
 164 inline bool DecodeBase58Check(const std::string& str, std::vector<unsigned char>& vchRet)
 165 {
 166     return DecodeBase58Check(str.c_str(), vchRet);
 167 }
 168
 169
 170
 171
 172
 173 /** Base class for all base58-encoded data */
 174 class CBase58Data
 175 {
 176 protected:
 177     // the version byte
 178     unsigned char nVersion;
 179
 180     // the actually encoded data
 181     std::vector<unsigned char> vchData;
 182
 183     CBase58Data()
 184     {
 185         nVersion = 0;
 186         vchData.clear();
 187     }
 188
 189     ~CBase58Data()
 190     {
 191         // zero the memory, as it may contain sensitive data
 192         if (!vchData.empty())
 193             memset(&vchData[0], 0, vchData.size());
 194     }
 195
 196     void SetData(int nVersionIn, const void* pdata, size_t nSize)
 197     {
 198         nVersion = nVersionIn;
 199         vchData.resize(nSize);
 200         if (!vchData.empty())
 201             memcpy(&vchData[0], pdata, nSize);
 202     }
 203
 204     void SetData(int nVersionIn, const unsigned char *pbegin, const unsigned char *pend)
 205     {
 206         SetData(nVersionIn, (void*)pbegin, pend - pbegin);
 207     }
 208
 209 public:
 210     bool SetString(const char* psz)
 211     {
 212         std::vector<unsigned char> vchTemp;
 213         DecodeBase58Check(psz, vchTemp);
 214         if (vchTemp.empty())
 215         {
 216             vchData.clear();
 217             nVersion = 0;
 218             return false;
 219         }
 220         nVersion = vchTemp[0];
 221         vchData.resize(vchTemp.size() - 1);
 222         if (!vchData.empty())
 223             memcpy(&vchData[0], &vchTemp[1], vchData.size());
 224         memset(&vchTemp[0], 0, vchTemp.size());
 225         return true;
 226     }
 227
 228     bool SetString(const std::string& str)
 229     {
 230         return SetString(str.c_str());
 231     }
 232
 233     std::string ToString() const
 234     {
 235         std::vector<unsigned char> vch(1, nVersion);
 236         vch.insert(vch.end(), vchData.begin(), vchData.end());
 237         return EncodeBase58Check(vch);
 238     }
 239
 240     int CompareTo(const CBase58Data& b58) const
 241     {
 242         if (nVersion < b58.nVersion) return -1;
 243         if (nVersion > b58.nVersion) return  1;
 244         if (vchData < b58.vchData)   return -1;
 245         if (vchData > b58.vchData)   return  1;
 246         return 0;
 247     }
 248
 249     bool operator==(const CBase58Data& b58) const { return CompareTo(b58) == 0; }
 250     bool operator<=(const CBase58Data& b58) const { return CompareTo(b58) <= 0; }
 251     bool operator>=(const CBase58Data& b58) const { return CompareTo(b58) >= 0; }
 252     bool operator< (const CBase58Data& b58) const { return CompareTo(b58) <  0; }
 253     bool operator> (const CBase58Data& b58) const { return CompareTo(b58) >  0; }
 254 };
 255
 256 /** base58-encoded Bitcoin addresses.
 257  * Public-key-hash-addresses have version 0 (or 111 testnet).
 258  * The data vector contains RIPEMD160(SHA256(pubkey)), where pubkey is the serialized public key.
 259  * Script-hash-addresses have version 5 (or 196 testnet).
 260  * The data vector contains RIPEMD160(SHA256(cscript)), where cscript is the serialized redemption script.
 261  */
 262 class CBitcoinAddress;
 263 class CBitcoinAddressVisitor : public boost::static_visitor<bool>
 264 {
 265 private:
 266     CBitcoinAddress *addr;
 267 public:
 268     CBitcoinAddressVisitor(CBitcoinAddress *addrIn) : addr(addrIn) { }
 269     bool operator()(const CKeyID &id) const;
 270     bool operator()(const CScriptID &id) const;
 271     bool operator()(const CNoDestination &no) const;
 272 };
 273
 274 class CBitcoinAddress : public CBase58Data
 275 {
 276 public:
 277     enum
 278     {
 279         PUBKEY_ADDRESS = 0,
 280         SCRIPT_ADDRESS = 5,
 281         PUBKEY_ADDRESS_TEST = 111,
 282         SCRIPT_ADDRESS_TEST = 196,
 283     };
 284
 285     bool Set(const CKeyID &id) {
 286         SetData(fTestNet ? PUBKEY_ADDRESS_TEST : PUBKEY_ADDRESS, &id, 20);
 287         return true;
 288     }
 289
 290     bool Set(const CScriptID &id) {
 291         SetData(fTestNet ? SCRIPT_ADDRESS_TEST : SCRIPT_ADDRESS, &id, 20);
 292         return true;
 293     }
 294
 295     bool Set(const CTxDestination &dest)
 296     {
 297         return boost::apply_visitor(CBitcoinAddressVisitor(this), dest);
 298     }
 299
 300     bool IsValid() const
 301     {
 302         unsigned int nExpectedSize = 20;
 303         bool fExpectTestNet = false;
 304         switch(nVersion)
 305         {
 306             case PUBKEY_ADDRESS:
 307                 nExpectedSize = 20; // Hash of public key
 308                 fExpectTestNet = false;
 309                 break;
 310             case SCRIPT_ADDRESS:
 311                 nExpectedSize = 20; // Hash of CScript
 312                 fExpectTestNet = false;
 313                 break;
 314
 315             case PUBKEY_ADDRESS_TEST:
 316                 nExpectedSize = 20;
 317                 fExpectTestNet = true;
 318                 break;
 319             case SCRIPT_ADDRESS_TEST:
 320                 nExpectedSize = 20;
 321                 fExpectTestNet = true;
 322                 break;
 323
 324             default:
 325                 return false;
 326         }
 327         return fExpectTestNet == fTestNet && vchData.size() == nExpectedSize;
 328     }
 329
 330     CBitcoinAddress()
 331     {
 332     }
 333
 334     CBitcoinAddress(const CTxDestination &dest)
 335     {
 336         Set(dest);
 337     }
 338
 339     CBitcoinAddress(const std::string& strAddress)
 340     {
 341         SetString(strAddress);
 342     }
 343
 344     CBitcoinAddress(const char* pszAddress)
 345     {
 346         SetString(pszAddress);
 347     }
 348
 349     CTxDestination Get() const {
 350         if (!IsValid())
 351             return CNoDestination();
 352         switch (nVersion) {
 353         case PUBKEY_ADDRESS:
 354         case PUBKEY_ADDRESS_TEST: {
 355             uint160 id;
 356             memcpy(&id, &vchData[0], 20);
 357             return CKeyID(id);
 358         }
 359         case SCRIPT_ADDRESS:
 360         case SCRIPT_ADDRESS_TEST: {
 361             uint160 id;
 362             memcpy(&id, &vchData[0], 20);
 363             return CScriptID(id);
 364         }
 365         }
 366         return CNoDestination();
 367     }
 368
 369     bool GetKeyID(CKeyID &keyID) const {
 370         if (!IsValid())
 371             return false;
 372         switch (nVersion) {
 373         case PUBKEY_ADDRESS:
 374         case PUBKEY_ADDRESS_TEST: {
 375             uint160 id;
 376             memcpy(&id, &vchData[0], 20);
 377             keyID = CKeyID(id);
 378             return true;
 379         }
 380         default: return false;
 381         }
 382     }
 383
 384     bool IsScript() const {
 385         if (!IsValid())
 386             return false;
 387         switch (nVersion) {
 388         case SCRIPT_ADDRESS:
 389         case SCRIPT_ADDRESS_TEST: {
 390             return true;
 391         }
 392         default: return false;
 393         }
 394     }
 395 };
 396
 397 bool inline CBitcoinAddressVisitor::operator()(const CKeyID &id) const         { return addr->Set(id); }
 398 bool inline CBitcoinAddressVisitor::operator()(const CScriptID &id) const      { return addr->Set(id); }
 399 bool inline CBitcoinAddressVisitor::operator()(const CNoDestination &id) const { return false; }
 400
 401 /** A base58-encoded secret key */
 402 class CBitcoinSecret : public CBase58Data
 403 {
 404 public:
 405     void SetSecret(const CSecret& vchSecret, bool fCompressed)
 406     {
 407         assert(vchSecret.size() == 32);
 408         SetData(fTestNet ? 239 : 128, &vchSecret[0], vchSecret.size());
 409         if (fCompressed)
 410             vchData.push_back(1);
 411     }
 412
 413     CSecret GetSecret(bool &fCompressedOut)
 414     {
 415         CSecret vchSecret;
 416         vchSecret.resize(32);
 417         memcpy(&vchSecret[0], &vchData[0], 32);
 418         fCompressedOut = vchData.size() == 33;
 419         return vchSecret;
 420     }
 421
 422     bool IsValid() const
 423     {
 424         bool fExpectTestNet = false;
 425         switch(nVersion)
 426         {
 427             case 128:
 428                 break;
 429
 430             case 239:
 431                 fExpectTestNet = true;
 432                 break;
 433
 434             default:
 435                 return false;
 436         }
 437         return fExpectTestNet == fTestNet && (vchData.size() == 32 || (vchData.size() == 33 && vchData[32] == 1));
 438     }
 439
 440     bool SetString(const char* pszSecret)
 441     {
 442         return CBase58Data::SetString(pszSecret) && IsValid();
 443     }
 444
 445     bool SetString(const std::string& strSecret)
 446     {
 447         return SetString(strSecret.c_str());
 448     }
 449
 450     CBitcoinSecret(const CSecret& vchSecret, bool fCompressed)
 451     {
 452         SetSecret(vchSecret, fCompressed);
 453     }
 454
 455     CBitcoinSecret()
 456     {
 457     }
 458 };
 459
 460 #endif