base58.h

   1 // Copyright (c) 2009-2010 Satoshi Nakamoto
   2 // Distributed under the MIT/X11 software license, see the accompanying
   3 // file license.txt or http://www.opensource.org/licenses/mit-license.php.
   4
   5
   6 //
   7 // Why base-58 instead of standard base-64 encoding?
   8 // - Don't want 0OIl characters that look the same in some fonts and
   9 //      could be used to create visually identical looking account numbers.
  10 // - A string with non-alphanumeric characters is not as easily accepted as an account number.
  11 // - E-mail usually won't line-break if there's no punctuation to break at.
  12 // - Doubleclicking selects the whole number as one word if it's all alphanumeric.
  13 //
  14
  15
  16 static const char* pszBase58 = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
  17
  18
  19 inline string EncodeBase58(const unsigned char* pbegin, const unsigned char* pend)
  20 {
  21     CAutoBN_CTX pctx;
  22     CBigNum bn58 = 58;
  23     CBigNum bn0 = 0;
  24
  25     // Convert big endian data to little endian
  26     // Extra zero at the end make sure bignum will interpret as a positive number
  27     vector<unsigned char> vchTmp(pend-pbegin+1, 0);
  28     reverse_copy(pbegin, pend, vchTmp.begin());
  29
  30     // Convert little endian data to bignum
  31     CBigNum bn;
  32     bn.setvch(vchTmp);
  33
  34     // Convert bignum to string
  35     string str;
  36     str.reserve((pend - pbegin) * 138 / 100 + 1);
  37     CBigNum dv;
  38     CBigNum rem;
  39     while (bn > bn0)
  40     {
  41         if (!BN_div(&dv, &rem, &bn, &bn58, pctx))
  42             throw bignum_error("EncodeBase58 : BN_div failed");
  43         bn = dv;
  44         unsigned int c = rem.getulong();
  45         str += pszBase58[c];
  46     }
  47
  48     // Leading zeroes encoded as base58 zeros
  49     for (const unsigned char* p = pbegin; p < pend && *p == 0; p++)
  50         str += pszBase58[0];
  51
  52     // Convert little endian string to big endian
  53     reverse(str.begin(), str.end());
  54     return str;
  55 }
  56
  57 inline string EncodeBase58(const vector<unsigned char>& vch)
  58 {
  59     return EncodeBase58(&vch[0], &vch[0] + vch.size());
  60 }
  61
  62 inline bool DecodeBase58(const char* psz, vector<unsigned char>& vchRet)
  63 {
  64     CAutoBN_CTX pctx;
  65     vchRet.clear();
  66     CBigNum bn58 = 58;
  67     CBigNum bn = 0;
  68     CBigNum bnChar;
  69     while (isspace(*psz))
  70         psz++;
  71
  72     // Convert big endian string to bignum
  73     for (const char* p = psz; *p; p++)
  74     {
  75         const char* p1 = strchr(pszBase58, *p);
  76         if (p1 == NULL)
  77         {
  78             while (isspace(*p))
  79                 p++;
  80             if (*p != '\0')
  81                 return false;
  82             break;
  83         }
  84         bnChar.setulong(p1 - pszBase58);
  85         if (!BN_mul(&bn, &bn, &bn58, pctx))
  86             throw bignum_error("DecodeBase58 : BN_mul failed");
  87         bn += bnChar;
  88     }
  89
  90     // Get bignum as little endian data
  91     vector<unsigned char> vchTmp = bn.getvch();
  92
  93     // Trim off sign byte if present
  94     if (vchTmp.size() >= 2 && vchTmp.end()[-1] == 0 && vchTmp.end()[-2] >= 0x80)
  95         vchTmp.erase(vchTmp.end()-1);
  96
  97     // Restore leading zeros
  98     int nLeadingZeros = 0;
  99     for (const char* p = psz; *p == pszBase58[0]; p++)
 100         nLeadingZeros++;
 101     vchRet.assign(nLeadingZeros + vchTmp.size(), 0);
 102
 103     // Convert little endian data to big endian
 104     reverse_copy(vchTmp.begin(), vchTmp.end(), vchRet.end() - vchTmp.size());
 105     return true;
 106 }
 107
 108 inline bool DecodeBase58(const string& str, vector<unsigned char>& vchRet)
 109 {
 110     return DecodeBase58(str.c_str(), vchRet);
 111 }
 112
 113
 114
 115
 116
 117 inline string EncodeBase58Check(const vector<unsigned char>& vchIn)
 118 {
 119     // add 4-byte hash check to the end
 120     vector<unsigned char> vch(vchIn);
 121     uint256 hash = Hash(vch.begin(), vch.end());
 122     vch.insert(vch.end(), (unsigned char*)&hash, (unsigned char*)&hash + 4);
 123     return EncodeBase58(vch);
 124 }
 125
 126 inline bool DecodeBase58Check(const char* psz, vector<unsigned char>& vchRet)
 127 {
 128     if (!DecodeBase58(psz, vchRet))
 129         return false;
 130     if (vchRet.size() < 4)
 131     {
 132         vchRet.clear();
 133         return false;
 134     }
 135     uint256 hash = Hash(vchRet.begin(), vchRet.end()-4);
 136     if (memcmp(&hash, &vchRet.end()[-4], 4) != 0)
 137     {
 138         vchRet.clear();
 139         return false;
 140     }
 141     vchRet.resize(vchRet.size()-4);
 142     return true;
 143 }
 144
 145 inline bool DecodeBase58Check(const string& str, vector<unsigned char>& vchRet)
 146 {
 147     return DecodeBase58Check(str.c_str(), vchRet);
 148 }
 149
 150
 151
 152
 153
 154
 155 #define ADDRESSVERSION   ((unsigned char)(fTestNet ? 111 : 0))
 156
 157 inline string Hash160ToAddress(uint160 hash160)
 158 {
 159     // add 1-byte version number to the front
 160     vector<unsigned char> vch(1, ADDRESSVERSION);
 161     vch.insert(vch.end(), UBEGIN(hash160), UEND(hash160));
 162     return EncodeBase58Check(vch);
 163 }
 164
 165 inline bool AddressToHash160(const char* psz, uint160& hash160Ret)
 166 {
 167     vector<unsigned char> vch;
 168     if (!DecodeBase58Check(psz, vch))
 169         return false;
 170     if (vch.empty())
 171         return false;
 172     unsigned char nVersion = vch[0];
 173     if (vch.size() != sizeof(hash160Ret) + 1)
 174         return false;
 175     memcpy(&hash160Ret, &vch[1], sizeof(hash160Ret));
 176     return (nVersion <= ADDRESSVERSION);
 177 }
 178
 179 inline bool AddressToHash160(const string& str, uint160& hash160Ret)
 180 {
 181     return AddressToHash160(str.c_str(), hash160Ret);
 182 }
 183
 184 inline bool IsValidBitcoinAddress(const char* psz)
 185 {
 186     uint160 hash160;
 187     return AddressToHash160(psz, hash160);
 188 }
 189
 190 inline bool IsValidBitcoinAddress(const string& str)
 191 {
 192     return IsValidBitcoinAddress(str.c_str());
 193 }
 194
 195
 196
 197
 198 inline string PubKeyToAddress(const vector<unsigned char>& vchPubKey)
 199 {
 200     return Hash160ToAddress(Hash160(vchPubKey));
 201 }