aboutsummaryrefslogtreecommitdiff
path: root/src/pubkey.h
blob: a508c238e4d3eb5b6dbdd6b04d962171141a9946 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2016 The Bitcoin Core developers
// Copyright (c) 2017 The Zcash developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#ifndef BITCOIN_PUBKEY_H
#define BITCOIN_PUBKEY_H

#include "hash.h"
#include "serialize.h"
#include "uint256.h"

#include <stdexcept>
#include <vector>

/**
 * secp256k1:
 */
const unsigned int PUBLIC_KEY_SIZE             = 65;
const unsigned int COMPRESSED_PUBLIC_KEY_SIZE  = 33;
const unsigned int SIGNATURE_SIZE              = 72;
const unsigned int COMPACT_SIGNATURE_SIZE      = 65;
/**
 * see www.keylength.com
 * script supports up to 75 for single byte push
 */

const unsigned int BIP32_EXTKEY_SIZE = 74;

/** A reference to a CKey: the Hash160 of its serialized public key */
class CKeyID : public uint160
{
public:
    CKeyID() : uint160() {}
    CKeyID(const uint160& in) : uint160(in) {}
};

typedef uint256 ChainCode;

/** An encapsulated public key. */
class CPubKey
{
private:

    /**
     * Just store the serialized data.
     * Its length can very cheaply be computed from the first byte.
     */
    unsigned char vch[PUBLIC_KEY_SIZE];
    static_assert(
        PUBLIC_KEY_SIZE >= COMPRESSED_PUBLIC_KEY_SIZE,
        "COMPRESSED_PUBLIC_KEY_SIZE is larger than PUBLIC_KEY_SIZE");

    //! Compute the length of a pubkey with a given first byte.
    unsigned int static GetLen(unsigned char chHeader)
    {
        if (chHeader == 2 || chHeader == 3)
            return COMPRESSED_PUBLIC_KEY_SIZE;
        if (chHeader == 4 || chHeader == 6 || chHeader == 7)
            return PUBLIC_KEY_SIZE;
        return 0;
    }

    //! Set this key data to be invalid
    void Invalidate()
    {
        vch[0] = 0xFF;
    }

public:
    //! Construct an invalid public key.
    CPubKey()
    {
        Invalidate();
    }

    //! Initialize a public key using begin/end iterators to byte data.
    template <typename T>
    void Set(const T pbegin, const T pend)
    {
        int len = pend == pbegin ? 0 : GetLen(pbegin[0]);
        if (len && len == (pend - pbegin))
            memcpy(vch, (unsigned char*)&pbegin[0], len);
        else
            Invalidate();
    }

    //! Construct a public key using begin/end iterators to byte data.
    template <typename T>
    CPubKey(const T pbegin, const T pend)
    {
        Set(pbegin, pend);
    }

    //! Construct a public key from a byte vector.
    CPubKey(const std::vector<unsigned char>& _vch)
    {
        Set(_vch.begin(), _vch.end());
    }

    //! Simple read-only vector-like interface to the pubkey data.
    unsigned int size() const { return GetLen(vch[0]); }
    const unsigned char* begin() const { return vch; }
    const unsigned char* end() const { return vch + size(); }
    const unsigned char& operator[](unsigned int pos) const { return vch[pos]; }

    //! Comparator implementation.
    friend bool operator==(const CPubKey& a, const CPubKey& b)
    {
        return a.vch[0] == b.vch[0] &&
               memcmp(a.vch, b.vch, a.size()) == 0;
    }
    friend bool operator!=(const CPubKey& a, const CPubKey& b)
    {
        return !(a == b);
    }
    friend bool operator<(const CPubKey& a, const CPubKey& b)
    {
        return a.vch[0] < b.vch[0] ||
               (a.vch[0] == b.vch[0] && memcmp(a.vch, b.vch, a.size()) < 0);
    }

    //! Implement serialization, as if this was a byte vector.
    template <typename Stream>
    void Serialize(Stream& s) const
    {
        unsigned int len = size();
        ::WriteCompactSize(s, len);
        s.write((char*)vch, len);
    }
    template <typename Stream>
    void Unserialize(Stream& s)
    {
        unsigned int len = ::ReadCompactSize(s);
        if (len <= PUBLIC_KEY_SIZE) {
            s.read((char*)vch, len);
        } else {
            // invalid pubkey, skip available data
            char dummy;
            while (len--)
                s.read(&dummy, 1);
            Invalidate();
        }
    }

    //! Get the KeyID of this public key (hash of its serialization)
    CKeyID GetID() const
    {
        return CKeyID(Hash160(vch, vch + size()));
    }

    //! Get the 256-bit hash of this public key.
    uint256 GetHash() const
    {
        return Hash(vch, vch + size());
    }

    /*
     * Check syntactic correctness.
     *
     * Note that this is consensus critical as CheckSig() calls it!
     */
    bool IsValid() const
    {
        return size() > 0;
    }

    //! fully validate whether this is a valid public key (more expensive than IsValid())
    bool IsFullyValid() const;

    //! Check whether this is a compressed public key.
    bool IsCompressed() const
    {
        return size() == COMPRESSED_PUBLIC_KEY_SIZE;
    }

    /**
     * Verify a DER signature (~72 bytes).
     * If this public key is not fully valid, the return value will be false.
     */
    bool Verify(const uint256& hash, const std::vector<unsigned char>& vchSig) const;

    /**
     * Check whether a signature is normalized (lower-S).
     */
    static bool CheckLowS(const std::vector<unsigned char>& vchSig);

    //! Recover a public key from a compact signature.
    bool RecoverCompact(const uint256& hash, const std::vector<unsigned char>& vchSig);

    //! Turn this public key into an uncompressed public key.
    bool Decompress();

    //! Derive BIP32 child pubkey.
    bool Derive(CPubKey& pubkeyChild, ChainCode &ccChild, unsigned int nChild, const ChainCode& cc) const;
};

struct CExtPubKey {
    unsigned char nDepth;
    unsigned char vchFingerprint[4];
    unsigned int nChild;
    ChainCode chaincode;
    CPubKey pubkey;

    friend bool operator==(const CExtPubKey &a, const CExtPubKey &b)
    {
        return a.nDepth == b.nDepth &&
            memcmp(&a.vchFingerprint[0], &b.vchFingerprint[0], sizeof(vchFingerprint)) == 0 &&
            a.nChild == b.nChild &&
            a.chaincode == b.chaincode &&
            a.pubkey == b.pubkey;
    }

    void Encode(unsigned char code[BIP32_EXTKEY_SIZE]) const;
    void Decode(const unsigned char code[BIP32_EXTKEY_SIZE]);
    bool Derive(CExtPubKey& out, unsigned int nChild) const;

    void Serialize(CSizeComputer& s) const
    {
        // Optimized implementation for ::GetSerializeSize that avoids copying.
        s.seek(BIP32_EXTKEY_SIZE + 1); // add one byte for the size (compact int)
    }
    template <typename Stream>
    void Serialize(Stream& s) const
    {
        unsigned int len = BIP32_EXTKEY_SIZE;
        ::WriteCompactSize(s, len);
        unsigned char code[BIP32_EXTKEY_SIZE];
        Encode(code);
        s.write((const char *)&code[0], len);
    }
    template <typename Stream>
    void Unserialize(Stream& s)
    {
        unsigned int len = ::ReadCompactSize(s);
        unsigned char code[BIP32_EXTKEY_SIZE];
        if (len != BIP32_EXTKEY_SIZE)
            throw std::runtime_error("Invalid extended key size\n");
        s.read((char *)&code[0], len);
        Decode(code);
    }
};

/** Users of this module must hold an ECCVerifyHandle. The constructor and
 *  destructor of these are not allowed to run in parallel, though. */
class ECCVerifyHandle
{
    static int refcount;

public:
    ECCVerifyHandle();
    ~ECCVerifyHandle();
};

#endif // BITCOIN_PUBKEY_H