aboutsummaryrefslogtreecommitdiff
path: root/src/key.h
blob: 552f12ad23642f96a6d4600a7b752f90abf744f6 (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
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2013 The Bitcoin developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#ifndef BITCOIN_KEY_H
#define BITCOIN_KEY_H

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

#include <stdexcept>
#include <vector>

// secp256k1:
// const unsigned int PRIVATE_KEY_SIZE = 279;
// const unsigned int PUBLIC_KEY_SIZE  = 65;
// const unsigned int SIGNATURE_SIZE   = 72;
//
// see www.keylength.com
// script supports up to 75 for single byte push

/** A reference to a CKey: the Hash160 of its serialized public key */
class CKeyID : public uint160
{
public:
    CKeyID() : uint160(0) { }
    CKeyID(const uint160 &in) : uint160(in) { }
};

/** A reference to a CScript: the Hash160 of its serialization (see script.h) */
class CScriptID : public uint160
{
public:
    CScriptID() : uint160(0) { }
    CScriptID(const uint160 &in) : uint160(in) { }
};

/** 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[65];

    // Compute the length of a pubkey with a given first byte.
    unsigned int static GetLen(unsigned char chHeader) {
        if (chHeader == 2 || chHeader == 3)
            return 33;
        if (chHeader == 4 || chHeader == 6 || chHeader == 7)
            return 65;
        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.
    unsigned int GetSerializeSize(int nType, int nVersion) const {
        return size() + 1;
    }
    template<typename Stream> void Serialize(Stream &s, int nType, int nVersion) const {
        unsigned int len = size();
        ::WriteCompactSize(s, len);
        s.write((char*)vch, len);
    }
    template<typename Stream> void Unserialize(Stream &s, int nType, int nVersion) {
        unsigned int len = ::ReadCompactSize(s);
        if (len <= 65) {
            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() == 33;
    }

    // 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;

    // 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, unsigned char ccChild[32], unsigned int nChild, const unsigned char cc[32]) const;
};


// secure_allocator is defined in allocators.h
// CPrivKey is a serialized private key, with all parameters included (279 bytes)
typedef std::vector<unsigned char, secure_allocator<unsigned char> > CPrivKey;

/** An encapsulated private key. */
class CKey {
private:
    // Whether this private key is valid. We check for correctness when modifying the key
    // data, so fValid should always correspond to the actual state.
    bool fValid;

    // Whether the public key corresponding to this private key is (to be) compressed.
    bool fCompressed;

    // The actual byte data
    unsigned char vch[32];

    // Check whether the 32-byte array pointed to be vch is valid keydata.
    bool static Check(const unsigned char *vch);
public:

    // Construct an invalid private key.
    CKey() : fValid(false) {
        LockObject(vch);
    }

    // Copy constructor. This is necessary because of memlocking.
    CKey(const CKey &secret) : fValid(secret.fValid), fCompressed(secret.fCompressed) {
        LockObject(vch);
        memcpy(vch, secret.vch, sizeof(vch));
    }

    // Destructor (again necessary because of memlocking).
    ~CKey() {
        UnlockObject(vch);
    }

    friend bool operator==(const CKey &a, const CKey &b) {
        return a.fCompressed == b.fCompressed && a.size() == b.size() &&
               memcmp(&a.vch[0], &b.vch[0], a.size()) == 0;
    }

    // Initialize using begin and end iterators to byte data.
    template<typename T>
    void Set(const T pbegin, const T pend, bool fCompressedIn) {
        if (pend - pbegin != 32) {
            fValid = false;
            return;
        }
        if (Check(&pbegin[0])) {
            memcpy(vch, (unsigned char*)&pbegin[0], 32);
            fValid = true;
            fCompressed = fCompressedIn;
        } else {
            fValid = false;
        }
    }

    // Simple read-only vector-like interface.
    unsigned int size() const { return (fValid ? 32 : 0); }
    const unsigned char *begin() const { return vch; }
    const unsigned char *end() const { return vch + size(); }

    // Check whether this private key is valid.
    bool IsValid() const { return fValid; }

    // Check whether the public key corresponding to this private key is (to be) compressed.
    bool IsCompressed() const { return fCompressed; }

    // Initialize from a CPrivKey (serialized OpenSSL private key data).
    bool SetPrivKey(const CPrivKey &vchPrivKey, bool fCompressed);

    // Generate a new private key using a cryptographic PRNG.
    void MakeNewKey(bool fCompressed);

    // Convert the private key to a CPrivKey (serialized OpenSSL private key data).
    // This is expensive.
    CPrivKey GetPrivKey() const;

    // Compute the public key from a private key.
    // This is expensive.
    CPubKey GetPubKey() const;

    // Create a DER-serialized signature.
    bool Sign(const uint256 &hash, std::vector<unsigned char>& vchSig) const;

    // Create a compact signature (65 bytes), which allows reconstructing the used public key.
    // The format is one header byte, followed by two times 32 bytes for the serialized r and s values.
    // The header byte: 0x1B = first key with even y, 0x1C = first key with odd y,
    //                  0x1D = second key with even y, 0x1E = second key with odd y,
    //                  add 0x04 for compressed keys.
    bool SignCompact(const uint256 &hash, std::vector<unsigned char>& vchSig) const;

    // Derive BIP32 child key.
    bool Derive(CKey& keyChild, unsigned char ccChild[32], unsigned int nChild, const unsigned char cc[32]) const;

    // Load private key and check that public key matches.
    bool Load(CPrivKey &privkey, CPubKey &vchPubKey, bool fSkipCheck);

    // Check whether an element of a signature (r or s) is valid.
    static bool CheckSignatureElement(const unsigned char *vch, int len, bool half);
};

struct CExtPubKey {
    unsigned char nDepth;
    unsigned char vchFingerprint[4];
    unsigned int nChild;
    unsigned char vchChainCode[32];
    CPubKey pubkey;

    friend bool operator==(const CExtPubKey &a, const CExtPubKey &b) {
        return a.nDepth == b.nDepth && memcmp(&a.vchFingerprint[0], &b.vchFingerprint[0], 4) == 0 && a.nChild == b.nChild &&
               memcmp(&a.vchChainCode[0], &b.vchChainCode[0], 32) == 0 && a.pubkey == b.pubkey;
    }

    void Encode(unsigned char code[74]) const;
    void Decode(const unsigned char code[74]);
    bool Derive(CExtPubKey &out, unsigned int nChild) const;
};

struct CExtKey {
    unsigned char nDepth;
    unsigned char vchFingerprint[4];
    unsigned int nChild;
    unsigned char vchChainCode[32];
    CKey key;

    friend bool operator==(const CExtKey &a, const CExtKey &b) {
        return a.nDepth == b.nDepth && memcmp(&a.vchFingerprint[0], &b.vchFingerprint[0], 4) == 0 && a.nChild == b.nChild &&
               memcmp(&a.vchChainCode[0], &b.vchChainCode[0], 32) == 0 && a.key == b.key;
    }

    void Encode(unsigned char code[74]) const;
    void Decode(const unsigned char code[74]);
    bool Derive(CExtKey &out, unsigned int nChild) const;
    CExtPubKey Neuter() const;
    void SetMaster(const unsigned char *seed, unsigned int nSeedLen);
};

/** Check that required EC support is available at runtime */
bool ECC_InitSanityCheck(void);

#endif // BITCOIN_KEY_H