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.
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.
14 #ifndef BITCOIN_BASE58_H
15 #define BITCOIN_BASE58_H
21 static const char* pszBase58 = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
24 inline std::string EncodeBase58(const unsigned char* pbegin, const unsigned char* pend)
30 // Convert big endian data to little endian
31 // Extra zero at the end make sure bignum will interpret as a positive number
32 std::vector<unsigned char> vchTmp(pend-pbegin+1, 0);
33 reverse_copy(pbegin, pend, vchTmp.begin());
35 // Convert little endian data to bignum
39 // Convert bignum to std::string
41 // Expected size increase from base58 conversion is approximately 137%
42 // use 138% to be safe
43 str.reserve((pend - pbegin) * 138 / 100 + 1);
48 if (!BN_div(&dv, &rem, &bn, &bn58, pctx))
49 throw bignum_error("EncodeBase58 : BN_div failed");
51 unsigned int c = rem.getulong();
55 // Leading zeroes encoded as base58 zeros
56 for (const unsigned char* p = pbegin; p < pend && *p == 0; p++)
59 // Convert little endian std::string to big endian
60 reverse(str.begin(), str.end());
64 inline std::string EncodeBase58(const std::vector<unsigned char>& vch)
66 return EncodeBase58(&vch[0], &vch[0] + vch.size());
69 inline bool DecodeBase58(const char* psz, std::vector<unsigned char>& vchRet)
79 // Convert big endian string to bignum
80 for (const char* p = psz; *p; p++)
82 const char* p1 = strchr(pszBase58, *p);
91 bnChar.setulong(p1 - pszBase58);
92 if (!BN_mul(&bn, &bn, &bn58, pctx))
93 throw bignum_error("DecodeBase58 : BN_mul failed");
97 // Get bignum as little endian data
98 std::vector<unsigned char> vchTmp = bn.getvch();
100 // Trim off sign byte if present
101 if (vchTmp.size() >= 2 && vchTmp.end()[-1] == 0 && vchTmp.end()[-2] >= 0x80)
102 vchTmp.erase(vchTmp.end()-1);
104 // Restore leading zeros
105 int nLeadingZeros = 0;
106 for (const char* p = psz; *p == pszBase58[0]; p++)
108 vchRet.assign(nLeadingZeros + vchTmp.size(), 0);
110 // Convert little endian data to big endian
111 reverse_copy(vchTmp.begin(), vchTmp.end(), vchRet.end() - vchTmp.size());
115 inline bool DecodeBase58(const std::string& str, std::vector<unsigned char>& vchRet)
117 return DecodeBase58(str.c_str(), vchRet);
124 inline std::string EncodeBase58Check(const std::vector<unsigned char>& vchIn)
126 // add 4-byte hash check to the end
127 std::vector<unsigned char> vch(vchIn);
128 uint256 hash = Hash(vch.begin(), vch.end());
129 vch.insert(vch.end(), (unsigned char*)&hash, (unsigned char*)&hash + 4);
130 return EncodeBase58(vch);
133 inline bool DecodeBase58Check(const char* psz, std::vector<unsigned char>& vchRet)
135 if (!DecodeBase58(psz, vchRet))
137 if (vchRet.size() < 4)
142 uint256 hash = Hash(vchRet.begin(), vchRet.end()-4);
143 if (memcmp(&hash, &vchRet.end()[-4], 4) != 0)
148 vchRet.resize(vchRet.size()-4);
152 inline bool DecodeBase58Check(const std::string& str, std::vector<unsigned char>& vchRet)
154 return DecodeBase58Check(str.c_str(), vchRet);
162 class CBitcoinAddress
165 unsigned char nVersion;
166 std::vector<unsigned char> vchData;
169 bool SetAddress(const uint160& hash160)
171 nVersion = fTestNet ? 111 : 0;
173 memcpy(&vchData[0], &hash160, 20);
177 bool SetAddress(const char* pszAddress)
179 std::vector<unsigned char> vchTemp;
180 DecodeBase58Check(pszAddress, vchTemp);
187 nVersion = vchTemp[0];
188 vchData.resize(vchTemp.size() - 1);
189 memcpy(&vchData[0], &vchTemp[1], vchData.size());
193 bool SetAddress(const std::string& strAddress)
195 return SetAddress(strAddress.c_str());
198 bool SetAddress(const std::vector<unsigned char>& vchPubKey)
200 return SetAddress(Hash160(vchPubKey));
205 int nExpectedSize = 20;
206 bool fExpectTestNet = false;
213 fExpectTestNet = true;
219 return fExpectTestNet == fTestNet && vchData.size() == nExpectedSize;
228 CBitcoinAddress(uint160 hash160In)
230 SetAddress(hash160In);
233 CBitcoinAddress(const std::vector<unsigned char>& vchPubKey)
235 SetAddress(vchPubKey);
238 CBitcoinAddress(const std::string& strAddress)
240 SetAddress(strAddress);
243 CBitcoinAddress(const char* pszAddress)
245 SetAddress(pszAddress);
248 std::string ToString() const
250 std::vector<unsigned char> vch(1, nVersion);
251 vch.insert(vch.end(), vchData.begin(), vchData.end());
252 return EncodeBase58Check(vch);
255 uint160 GetHash160() const
257 assert(vchData.size() == 20);
259 memcpy(&hash160, &vchData[0], 20);
263 int CompareTo(const CBitcoinAddress& address) const
265 if (nVersion < address.nVersion) return -1;
266 if (nVersion < address.nVersion) return 1;
267 if (vchData < address.vchData) return -1;
268 if (vchData > address.vchData) return 1;
272 bool operator==(const CBitcoinAddress& address) const { return CompareTo(address) == 0; }
273 bool operator<=(const CBitcoinAddress& address) const { return CompareTo(address) <= 0; }
274 bool operator>=(const CBitcoinAddress& address) const { return CompareTo(address) >= 0; }
275 bool operator< (const CBitcoinAddress& address) const { return CompareTo(address) < 0; }
276 bool operator> (const CBitcoinAddress& address) const { return CompareTo(address) > 0; }