Line data Source code
1 : // Copyright (c) 2009-2022 The Bitcoin Core developers
2 : // Copyright (c) 2017 The Zcash developers
3 : // Distributed under the MIT software license, see the accompanying
4 : // file COPYING or http://www.opensource.org/licenses/mit-license.php.
5 :
6 : #include <key.h>
7 :
8 : #include <crypto/common.h>
9 : #include <crypto/hmac_sha512.h>
10 : #include <hash.h>
11 : #include <random.h>
12 :
13 : #include <secp256k1.h>
14 : #include <secp256k1_ellswift.h>
15 : #include <secp256k1_extrakeys.h>
16 : #include <secp256k1_recovery.h>
17 : #include <secp256k1_schnorrsig.h>
18 :
19 : static secp256k1_context* secp256k1_context_sign = nullptr;
20 :
21 : /** These functions are taken from the libsecp256k1 distribution and are very ugly. */
22 :
23 : /**
24 : * This parses a format loosely based on a DER encoding of the ECPrivateKey type from
25 : * section C.4 of SEC 1 <https://www.secg.org/sec1-v2.pdf>, with the following caveats:
26 : *
27 : * * The octet-length of the SEQUENCE must be encoded as 1 or 2 octets. It is not
28 : * required to be encoded as one octet if it is less than 256, as DER would require.
29 : * * The octet-length of the SEQUENCE must not be greater than the remaining
30 : * length of the key encoding, but need not match it (i.e. the encoding may contain
31 : * junk after the encoded SEQUENCE).
32 : * * The privateKey OCTET STRING is zero-filled on the left to 32 octets.
33 : * * Anything after the encoding of the privateKey OCTET STRING is ignored, whether
34 : * or not it is validly encoded DER.
35 : *
36 : * out32 must point to an output buffer of length at least 32 bytes.
37 : */
38 0 : int ec_seckey_import_der(const secp256k1_context* ctx, unsigned char *out32, const unsigned char *seckey, size_t seckeylen) {
39 0 : const unsigned char *end = seckey + seckeylen;
40 0 : memset(out32, 0, 32);
41 : /* sequence header */
42 0 : if (end - seckey < 1 || *seckey != 0x30u) {
43 0 : return 0;
44 : }
45 0 : seckey++;
46 : /* sequence length constructor */
47 0 : if (end - seckey < 1 || !(*seckey & 0x80u)) {
48 0 : return 0;
49 : }
50 0 : ptrdiff_t lenb = *seckey & ~0x80u; seckey++;
51 0 : if (lenb < 1 || lenb > 2) {
52 0 : return 0;
53 : }
54 0 : if (end - seckey < lenb) {
55 0 : return 0;
56 : }
57 : /* sequence length */
58 0 : ptrdiff_t len = seckey[lenb-1] | (lenb > 1 ? seckey[lenb-2] << 8 : 0u);
59 0 : seckey += lenb;
60 0 : if (end - seckey < len) {
61 0 : return 0;
62 : }
63 : /* sequence element 0: version number (=1) */
64 0 : if (end - seckey < 3 || seckey[0] != 0x02u || seckey[1] != 0x01u || seckey[2] != 0x01u) {
65 0 : return 0;
66 : }
67 0 : seckey += 3;
68 : /* sequence element 1: octet string, up to 32 bytes */
69 0 : if (end - seckey < 2 || seckey[0] != 0x04u) {
70 0 : return 0;
71 : }
72 0 : ptrdiff_t oslen = seckey[1];
73 0 : seckey += 2;
74 0 : if (oslen > 32 || end - seckey < oslen) {
75 0 : return 0;
76 : }
77 0 : memcpy(out32 + (32 - oslen), seckey, oslen);
78 0 : if (!secp256k1_ec_seckey_verify(ctx, out32)) {
79 0 : memset(out32, 0, 32);
80 0 : return 0;
81 : }
82 0 : return 1;
83 0 : }
84 :
85 : /**
86 : * This serializes to a DER encoding of the ECPrivateKey type from section C.4 of SEC 1
87 : * <https://www.secg.org/sec1-v2.pdf>. The optional parameters and publicKey fields are
88 : * included.
89 : *
90 : * seckey must point to an output buffer of length at least CKey::SIZE bytes.
91 : * seckeylen must initially be set to the size of the seckey buffer. Upon return it
92 : * will be set to the number of bytes used in the buffer.
93 : * key32 must point to a 32-byte raw private key.
94 : */
95 0 : int ec_seckey_export_der(const secp256k1_context *ctx, unsigned char *seckey, size_t *seckeylen, const unsigned char *key32, bool compressed) {
96 0 : assert(*seckeylen >= CKey::SIZE);
97 : secp256k1_pubkey pubkey;
98 0 : size_t pubkeylen = 0;
99 0 : if (!secp256k1_ec_pubkey_create(ctx, &pubkey, key32)) {
100 0 : *seckeylen = 0;
101 0 : return 0;
102 : }
103 0 : if (compressed) {
104 : static const unsigned char begin[] = {
105 : 0x30,0x81,0xD3,0x02,0x01,0x01,0x04,0x20
106 : };
107 : static const unsigned char middle[] = {
108 : 0xA0,0x81,0x85,0x30,0x81,0x82,0x02,0x01,0x01,0x30,0x2C,0x06,0x07,0x2A,0x86,0x48,
109 : 0xCE,0x3D,0x01,0x01,0x02,0x21,0x00,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
110 : 0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
111 : 0xFF,0xFF,0xFE,0xFF,0xFF,0xFC,0x2F,0x30,0x06,0x04,0x01,0x00,0x04,0x01,0x07,0x04,
112 : 0x21,0x02,0x79,0xBE,0x66,0x7E,0xF9,0xDC,0xBB,0xAC,0x55,0xA0,0x62,0x95,0xCE,0x87,
113 : 0x0B,0x07,0x02,0x9B,0xFC,0xDB,0x2D,0xCE,0x28,0xD9,0x59,0xF2,0x81,0x5B,0x16,0xF8,
114 : 0x17,0x98,0x02,0x21,0x00,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
115 : 0xFF,0xFF,0xFF,0xFF,0xFE,0xBA,0xAE,0xDC,0xE6,0xAF,0x48,0xA0,0x3B,0xBF,0xD2,0x5E,
116 : 0x8C,0xD0,0x36,0x41,0x41,0x02,0x01,0x01,0xA1,0x24,0x03,0x22,0x00
117 : };
118 0 : unsigned char *ptr = seckey;
119 0 : memcpy(ptr, begin, sizeof(begin)); ptr += sizeof(begin);
120 0 : memcpy(ptr, key32, 32); ptr += 32;
121 0 : memcpy(ptr, middle, sizeof(middle)); ptr += sizeof(middle);
122 0 : pubkeylen = CPubKey::COMPRESSED_SIZE;
123 0 : secp256k1_ec_pubkey_serialize(ctx, ptr, &pubkeylen, &pubkey, SECP256K1_EC_COMPRESSED);
124 0 : ptr += pubkeylen;
125 0 : *seckeylen = ptr - seckey;
126 0 : assert(*seckeylen == CKey::COMPRESSED_SIZE);
127 0 : } else {
128 : static const unsigned char begin[] = {
129 : 0x30,0x82,0x01,0x13,0x02,0x01,0x01,0x04,0x20
130 : };
131 : static const unsigned char middle[] = {
132 : 0xA0,0x81,0xA5,0x30,0x81,0xA2,0x02,0x01,0x01,0x30,0x2C,0x06,0x07,0x2A,0x86,0x48,
133 : 0xCE,0x3D,0x01,0x01,0x02,0x21,0x00,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
134 : 0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
135 : 0xFF,0xFF,0xFE,0xFF,0xFF,0xFC,0x2F,0x30,0x06,0x04,0x01,0x00,0x04,0x01,0x07,0x04,
136 : 0x41,0x04,0x79,0xBE,0x66,0x7E,0xF9,0xDC,0xBB,0xAC,0x55,0xA0,0x62,0x95,0xCE,0x87,
137 : 0x0B,0x07,0x02,0x9B,0xFC,0xDB,0x2D,0xCE,0x28,0xD9,0x59,0xF2,0x81,0x5B,0x16,0xF8,
138 : 0x17,0x98,0x48,0x3A,0xDA,0x77,0x26,0xA3,0xC4,0x65,0x5D,0xA4,0xFB,0xFC,0x0E,0x11,
139 : 0x08,0xA8,0xFD,0x17,0xB4,0x48,0xA6,0x85,0x54,0x19,0x9C,0x47,0xD0,0x8F,0xFB,0x10,
140 : 0xD4,0xB8,0x02,0x21,0x00,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
141 : 0xFF,0xFF,0xFF,0xFF,0xFE,0xBA,0xAE,0xDC,0xE6,0xAF,0x48,0xA0,0x3B,0xBF,0xD2,0x5E,
142 : 0x8C,0xD0,0x36,0x41,0x41,0x02,0x01,0x01,0xA1,0x44,0x03,0x42,0x00
143 : };
144 0 : unsigned char *ptr = seckey;
145 0 : memcpy(ptr, begin, sizeof(begin)); ptr += sizeof(begin);
146 0 : memcpy(ptr, key32, 32); ptr += 32;
147 0 : memcpy(ptr, middle, sizeof(middle)); ptr += sizeof(middle);
148 0 : pubkeylen = CPubKey::SIZE;
149 0 : secp256k1_ec_pubkey_serialize(ctx, ptr, &pubkeylen, &pubkey, SECP256K1_EC_UNCOMPRESSED);
150 0 : ptr += pubkeylen;
151 0 : *seckeylen = ptr - seckey;
152 0 : assert(*seckeylen == CKey::SIZE);
153 : }
154 0 : return 1;
155 0 : }
156 :
157 0 : bool CKey::Check(const unsigned char *vch) {
158 0 : return secp256k1_ec_seckey_verify(secp256k1_context_sign, vch);
159 : }
160 :
161 0 : void CKey::MakeNewKey(bool fCompressedIn) {
162 0 : do {
163 0 : GetStrongRandBytes(keydata);
164 0 : } while (!Check(keydata.data()));
165 0 : fValid = true;
166 0 : fCompressed = fCompressedIn;
167 0 : }
168 :
169 0 : bool CKey::Negate()
170 : {
171 0 : assert(fValid);
172 0 : return secp256k1_ec_seckey_negate(secp256k1_context_sign, keydata.data());
173 : }
174 :
175 0 : CPrivKey CKey::GetPrivKey() const {
176 0 : assert(fValid);
177 0 : CPrivKey seckey;
178 : int ret;
179 : size_t seckeylen;
180 0 : seckey.resize(SIZE);
181 0 : seckeylen = SIZE;
182 0 : ret = ec_seckey_export_der(secp256k1_context_sign, seckey.data(), &seckeylen, begin(), fCompressed);
183 0 : assert(ret);
184 0 : seckey.resize(seckeylen);
185 0 : return seckey;
186 0 : }
187 :
188 0 : CPubKey CKey::GetPubKey() const {
189 0 : assert(fValid);
190 : secp256k1_pubkey pubkey;
191 0 : size_t clen = CPubKey::SIZE;
192 0 : CPubKey result;
193 0 : int ret = secp256k1_ec_pubkey_create(secp256k1_context_sign, &pubkey, begin());
194 0 : assert(ret);
195 0 : secp256k1_ec_pubkey_serialize(secp256k1_context_sign, (unsigned char*)result.begin(), &clen, &pubkey, fCompressed ? SECP256K1_EC_COMPRESSED : SECP256K1_EC_UNCOMPRESSED);
196 0 : assert(result.size() == clen);
197 0 : assert(result.IsValid());
198 0 : return result;
199 : }
200 :
201 : // Check that the sig has a low R value and will be less than 71 bytes
202 0 : bool SigHasLowR(const secp256k1_ecdsa_signature* sig)
203 : {
204 : unsigned char compact_sig[64];
205 0 : secp256k1_ecdsa_signature_serialize_compact(secp256k1_context_sign, compact_sig, sig);
206 :
207 : // In DER serialization, all values are interpreted as big-endian, signed integers. The highest bit in the integer indicates
208 : // its signed-ness; 0 is positive, 1 is negative. When the value is interpreted as a negative integer, it must be converted
209 : // to a positive value by prepending a 0x00 byte so that the highest bit is 0. We can avoid this prepending by ensuring that
210 : // our highest bit is always 0, and thus we must check that the first byte is less than 0x80.
211 0 : return compact_sig[0] < 0x80;
212 : }
213 :
214 0 : bool CKey::Sign(const uint256 &hash, std::vector<unsigned char>& vchSig, bool grind, uint32_t test_case) const {
215 0 : if (!fValid)
216 0 : return false;
217 0 : vchSig.resize(CPubKey::SIGNATURE_SIZE);
218 0 : size_t nSigLen = CPubKey::SIGNATURE_SIZE;
219 0 : unsigned char extra_entropy[32] = {0};
220 0 : WriteLE32(extra_entropy, test_case);
221 : secp256k1_ecdsa_signature sig;
222 0 : uint32_t counter = 0;
223 0 : int ret = secp256k1_ecdsa_sign(secp256k1_context_sign, &sig, hash.begin(), begin(), secp256k1_nonce_function_rfc6979, (!grind && test_case) ? extra_entropy : nullptr);
224 :
225 : // Grind for low R
226 0 : while (ret && !SigHasLowR(&sig) && grind) {
227 0 : WriteLE32(extra_entropy, ++counter);
228 0 : ret = secp256k1_ecdsa_sign(secp256k1_context_sign, &sig, hash.begin(), begin(), secp256k1_nonce_function_rfc6979, extra_entropy);
229 : }
230 0 : assert(ret);
231 0 : secp256k1_ecdsa_signature_serialize_der(secp256k1_context_sign, vchSig.data(), &nSigLen, &sig);
232 0 : vchSig.resize(nSigLen);
233 : // Additional verification step to prevent using a potentially corrupted signature
234 : secp256k1_pubkey pk;
235 0 : ret = secp256k1_ec_pubkey_create(secp256k1_context_sign, &pk, begin());
236 0 : assert(ret);
237 0 : ret = secp256k1_ecdsa_verify(secp256k1_context_static, &sig, hash.begin(), &pk);
238 0 : assert(ret);
239 0 : return true;
240 0 : }
241 :
242 0 : bool CKey::VerifyPubKey(const CPubKey& pubkey) const {
243 0 : if (pubkey.IsCompressed() != fCompressed) {
244 0 : return false;
245 : }
246 : unsigned char rnd[8];
247 0 : std::string str = "Bitcoin key verification\n";
248 0 : GetRandBytes(rnd);
249 0 : uint256 hash{Hash(str, rnd)};
250 0 : std::vector<unsigned char> vchSig;
251 0 : Sign(hash, vchSig);
252 0 : return pubkey.Verify(hash, vchSig);
253 0 : }
254 :
255 0 : bool CKey::SignCompact(const uint256 &hash, std::vector<unsigned char>& vchSig) const {
256 0 : if (!fValid)
257 0 : return false;
258 0 : vchSig.resize(CPubKey::COMPACT_SIGNATURE_SIZE);
259 0 : int rec = -1;
260 : secp256k1_ecdsa_recoverable_signature rsig;
261 0 : int ret = secp256k1_ecdsa_sign_recoverable(secp256k1_context_sign, &rsig, hash.begin(), begin(), secp256k1_nonce_function_rfc6979, nullptr);
262 0 : assert(ret);
263 0 : ret = secp256k1_ecdsa_recoverable_signature_serialize_compact(secp256k1_context_sign, &vchSig[1], &rec, &rsig);
264 0 : assert(ret);
265 0 : assert(rec != -1);
266 0 : vchSig[0] = 27 + rec + (fCompressed ? 4 : 0);
267 : // Additional verification step to prevent using a potentially corrupted signature
268 : secp256k1_pubkey epk, rpk;
269 0 : ret = secp256k1_ec_pubkey_create(secp256k1_context_sign, &epk, begin());
270 0 : assert(ret);
271 0 : ret = secp256k1_ecdsa_recover(secp256k1_context_static, &rpk, &rsig, hash.begin());
272 0 : assert(ret);
273 0 : ret = secp256k1_ec_pubkey_cmp(secp256k1_context_static, &epk, &rpk);
274 0 : assert(ret == 0);
275 0 : return true;
276 0 : }
277 :
278 0 : bool CKey::SignSchnorr(const uint256& hash, Span<unsigned char> sig, const uint256* merkle_root, const uint256& aux) const
279 : {
280 0 : assert(sig.size() == 64);
281 : secp256k1_keypair keypair;
282 0 : if (!secp256k1_keypair_create(secp256k1_context_sign, &keypair, begin())) return false;
283 0 : if (merkle_root) {
284 : secp256k1_xonly_pubkey pubkey;
285 0 : if (!secp256k1_keypair_xonly_pub(secp256k1_context_sign, &pubkey, nullptr, &keypair)) return false;
286 : unsigned char pubkey_bytes[32];
287 0 : if (!secp256k1_xonly_pubkey_serialize(secp256k1_context_sign, pubkey_bytes, &pubkey)) return false;
288 0 : uint256 tweak = XOnlyPubKey(pubkey_bytes).ComputeTapTweakHash(merkle_root->IsNull() ? nullptr : merkle_root);
289 0 : if (!secp256k1_keypair_xonly_tweak_add(secp256k1_context_static, &keypair, tweak.data())) return false;
290 0 : }
291 0 : bool ret = secp256k1_schnorrsig_sign32(secp256k1_context_sign, sig.data(), hash.data(), &keypair, aux.data());
292 0 : if (ret) {
293 : // Additional verification step to prevent using a potentially corrupted signature
294 : secp256k1_xonly_pubkey pubkey_verify;
295 0 : ret = secp256k1_keypair_xonly_pub(secp256k1_context_static, &pubkey_verify, nullptr, &keypair);
296 0 : ret &= secp256k1_schnorrsig_verify(secp256k1_context_static, sig.data(), hash.begin(), 32, &pubkey_verify);
297 0 : }
298 0 : if (!ret) memory_cleanse(sig.data(), sig.size());
299 0 : memory_cleanse(&keypair, sizeof(keypair));
300 0 : return ret;
301 0 : }
302 :
303 0 : bool CKey::Load(const CPrivKey &seckey, const CPubKey &vchPubKey, bool fSkipCheck=false) {
304 0 : if (!ec_seckey_import_der(secp256k1_context_sign, (unsigned char*)begin(), seckey.data(), seckey.size()))
305 0 : return false;
306 0 : fCompressed = vchPubKey.IsCompressed();
307 0 : fValid = true;
308 :
309 0 : if (fSkipCheck)
310 0 : return true;
311 :
312 0 : return VerifyPubKey(vchPubKey);
313 0 : }
314 :
315 0 : bool CKey::Derive(CKey& keyChild, ChainCode &ccChild, unsigned int nChild, const ChainCode& cc) const {
316 0 : assert(IsValid());
317 0 : assert(IsCompressed());
318 0 : std::vector<unsigned char, secure_allocator<unsigned char>> vout(64);
319 0 : if ((nChild >> 31) == 0) {
320 0 : CPubKey pubkey = GetPubKey();
321 0 : assert(pubkey.size() == CPubKey::COMPRESSED_SIZE);
322 0 : BIP32Hash(cc, nChild, *pubkey.begin(), pubkey.begin()+1, vout.data());
323 0 : } else {
324 0 : assert(size() == 32);
325 0 : BIP32Hash(cc, nChild, 0, begin(), vout.data());
326 : }
327 0 : memcpy(ccChild.begin(), vout.data()+32, 32);
328 0 : memcpy((unsigned char*)keyChild.begin(), begin(), 32);
329 0 : bool ret = secp256k1_ec_seckey_tweak_add(secp256k1_context_sign, (unsigned char*)keyChild.begin(), vout.data());
330 0 : keyChild.fCompressed = true;
331 0 : keyChild.fValid = ret;
332 0 : return ret;
333 0 : }
334 :
335 0 : EllSwiftPubKey CKey::EllSwiftCreate(Span<const std::byte> ent32) const
336 : {
337 0 : assert(fValid);
338 0 : assert(ent32.size() == 32);
339 : std::array<std::byte, EllSwiftPubKey::size()> encoded_pubkey;
340 :
341 0 : auto success = secp256k1_ellswift_create(secp256k1_context_sign,
342 0 : UCharCast(encoded_pubkey.data()),
343 0 : keydata.data(),
344 0 : UCharCast(ent32.data()));
345 :
346 : // Should always succeed for valid keys (asserted above).
347 0 : assert(success);
348 0 : return {encoded_pubkey};
349 : }
350 :
351 0 : ECDHSecret CKey::ComputeBIP324ECDHSecret(const EllSwiftPubKey& their_ellswift, const EllSwiftPubKey& our_ellswift, bool initiating) const
352 : {
353 0 : assert(fValid);
354 :
355 : ECDHSecret output;
356 : // BIP324 uses the initiator as party A, and the responder as party B. Remap the inputs
357 : // accordingly:
358 0 : bool success = secp256k1_ellswift_xdh(secp256k1_context_sign,
359 0 : UCharCast(output.data()),
360 0 : UCharCast(initiating ? our_ellswift.data() : their_ellswift.data()),
361 0 : UCharCast(initiating ? their_ellswift.data() : our_ellswift.data()),
362 0 : keydata.data(),
363 0 : initiating ? 0 : 1,
364 0 : secp256k1_ellswift_xdh_hash_function_bip324,
365 : nullptr);
366 : // Should always succeed for valid keys (assert above).
367 0 : assert(success);
368 0 : return output;
369 : }
370 :
371 0 : bool CExtKey::Derive(CExtKey &out, unsigned int _nChild) const {
372 0 : if (nDepth == std::numeric_limits<unsigned char>::max()) return false;
373 0 : out.nDepth = nDepth + 1;
374 0 : CKeyID id = key.GetPubKey().GetID();
375 0 : memcpy(out.vchFingerprint, &id, 4);
376 0 : out.nChild = _nChild;
377 0 : return key.Derive(out.key, out.chaincode, _nChild, chaincode);
378 0 : }
379 :
380 0 : void CExtKey::SetSeed(Span<const std::byte> seed)
381 : {
382 : static const unsigned char hashkey[] = {'B','i','t','c','o','i','n',' ','s','e','e','d'};
383 0 : std::vector<unsigned char, secure_allocator<unsigned char>> vout(64);
384 0 : CHMAC_SHA512{hashkey, sizeof(hashkey)}.Write(UCharCast(seed.data()), seed.size()).Finalize(vout.data());
385 0 : key.Set(vout.data(), vout.data() + 32, true);
386 0 : memcpy(chaincode.begin(), vout.data() + 32, 32);
387 0 : nDepth = 0;
388 0 : nChild = 0;
389 0 : memset(vchFingerprint, 0, sizeof(vchFingerprint));
390 0 : }
391 :
392 0 : CExtPubKey CExtKey::Neuter() const {
393 0 : CExtPubKey ret;
394 0 : ret.nDepth = nDepth;
395 0 : memcpy(ret.vchFingerprint, vchFingerprint, 4);
396 0 : ret.nChild = nChild;
397 0 : ret.pubkey = key.GetPubKey();
398 0 : ret.chaincode = chaincode;
399 0 : return ret;
400 : }
401 :
402 0 : void CExtKey::Encode(unsigned char code[BIP32_EXTKEY_SIZE]) const {
403 0 : code[0] = nDepth;
404 0 : memcpy(code+1, vchFingerprint, 4);
405 0 : WriteBE32(code+5, nChild);
406 0 : memcpy(code+9, chaincode.begin(), 32);
407 0 : code[41] = 0;
408 0 : assert(key.size() == 32);
409 0 : memcpy(code+42, key.begin(), 32);
410 0 : }
411 :
412 0 : void CExtKey::Decode(const unsigned char code[BIP32_EXTKEY_SIZE]) {
413 0 : nDepth = code[0];
414 0 : memcpy(vchFingerprint, code+1, 4);
415 0 : nChild = ReadBE32(code+5);
416 0 : memcpy(chaincode.begin(), code+9, 32);
417 0 : key.Set(code+42, code+BIP32_EXTKEY_SIZE, true);
418 0 : if ((nDepth == 0 && (nChild != 0 || ReadLE32(vchFingerprint) != 0)) || code[41] != 0) key = CKey();
419 0 : }
420 :
421 0 : bool ECC_InitSanityCheck() {
422 0 : CKey key;
423 0 : key.MakeNewKey(true);
424 0 : CPubKey pubkey = key.GetPubKey();
425 0 : return key.VerifyPubKey(pubkey);
426 0 : }
427 :
428 1 : void ECC_Start() {
429 1 : assert(secp256k1_context_sign == nullptr);
430 :
431 1 : secp256k1_context *ctx = secp256k1_context_create(SECP256K1_CONTEXT_NONE);
432 1 : assert(ctx != nullptr);
433 :
434 : {
435 : // Pass in a random blinding seed to the secp256k1 context.
436 1 : std::vector<unsigned char, secure_allocator<unsigned char>> vseed(32);
437 1 : GetRandBytes(vseed);
438 1 : bool ret = secp256k1_context_randomize(ctx, vseed.data());
439 1 : assert(ret);
440 1 : }
441 :
442 1 : secp256k1_context_sign = ctx;
443 1 : }
444 :
445 1 : void ECC_Stop() {
446 1 : secp256k1_context *ctx = secp256k1_context_sign;
447 1 : secp256k1_context_sign = nullptr;
448 :
449 1 : if (ctx) {
450 1 : secp256k1_context_destroy(ctx);
451 1 : }
452 1 : }
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