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-rw-r--r--src/key.cpp180
1 files changed, 180 insertions, 0 deletions
diff --git a/src/key.cpp b/src/key.cpp
index f73708199a..7092b0e0c8 100644
--- a/src/key.cpp
+++ b/src/key.cpp
@@ -2,6 +2,7 @@
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+#include <openssl/bn.h>
#include <openssl/ecdsa.h>
#include <openssl/rand.h>
#include <openssl/obj_mac.h>
@@ -253,6 +254,57 @@ public:
ECDSA_SIG_free(sig);
return ret;
}
+
+ static bool TweakSecret(unsigned char vchSecretOut[32], const unsigned char vchSecretIn[32], const unsigned char vchTweak[32])
+ {
+ bool ret = true;
+ BN_CTX *ctx = BN_CTX_new();
+ BN_CTX_start(ctx);
+ BIGNUM *bnSecret = BN_CTX_get(ctx);
+ BIGNUM *bnTweak = BN_CTX_get(ctx);
+ BIGNUM *bnOrder = BN_CTX_get(ctx);
+ EC_GROUP *group = EC_GROUP_new_by_curve_name(NID_secp256k1);
+ EC_GROUP_get_order(group, bnOrder, ctx); // what a grossly inefficient way to get the (constant) group order...
+ BN_bin2bn(vchTweak, 32, bnTweak);
+ if (BN_cmp(bnTweak, bnOrder) >= 0)
+ ret = false; // extremely unlikely
+ BN_bin2bn(vchSecretIn, 32, bnSecret);
+ BN_add(bnSecret, bnSecret, bnTweak);
+ BN_nnmod(bnSecret, bnSecret, bnOrder, ctx);
+ if (BN_is_zero(bnSecret))
+ ret = false; // ridiculously unlikely
+ int nBits = BN_num_bits(bnSecret);
+ memset(vchSecretOut, 0, 32);
+ BN_bn2bin(bnSecret, &vchSecretOut[32-(nBits+7)/8]);
+ EC_GROUP_free(group);
+ BN_CTX_end(ctx);
+ BN_CTX_free(ctx);
+ return ret;
+ }
+
+ bool TweakPublic(const unsigned char vchTweak[32]) {
+ bool ret = true;
+ BN_CTX *ctx = BN_CTX_new();
+ BN_CTX_start(ctx);
+ BIGNUM *bnTweak = BN_CTX_get(ctx);
+ BIGNUM *bnOrder = BN_CTX_get(ctx);
+ BIGNUM *bnOne = BN_CTX_get(ctx);
+ const EC_GROUP *group = EC_KEY_get0_group(pkey);
+ EC_GROUP_get_order(group, bnOrder, ctx); // what a grossly inefficient way to get the (constant) group order...
+ BN_bin2bn(vchTweak, 32, bnTweak);
+ if (BN_cmp(bnTweak, bnOrder) >= 0)
+ ret = false; // extremely unlikely
+ EC_POINT *point = EC_POINT_dup(EC_KEY_get0_public_key(pkey), group);
+ BN_one(bnOne);
+ EC_POINT_mul(group, point, bnTweak, point, bnOne, ctx);
+ if (EC_POINT_is_at_infinity(group, point))
+ ret = false; // ridiculously unlikely
+ EC_KEY_set_public_key(pkey, point);
+ EC_POINT_free(point);
+ BN_CTX_end(ctx);
+ BN_CTX_free(ctx);
+ return ret;
+ }
};
}; // end of anonymous namespace
@@ -393,3 +445,131 @@ bool CPubKey::Decompress() {
key.GetPubKey(*this, false);
return true;
}
+
+void static BIP32Hash(const unsigned char chainCode[32], unsigned int nChild, unsigned char header, const unsigned char data[32], unsigned char output[64]) {
+ unsigned char num[4];
+ num[0] = (nChild >> 24) & 0xFF;
+ num[1] = (nChild >> 16) & 0xFF;
+ num[2] = (nChild >> 8) & 0xFF;
+ num[3] = (nChild >> 0) & 0xFF;
+ HMAC_SHA512_CTX ctx;
+ HMAC_SHA512_Init(&ctx, chainCode, 32);
+ HMAC_SHA512_Update(&ctx, &header, 1);
+ HMAC_SHA512_Update(&ctx, data, 32);
+ HMAC_SHA512_Update(&ctx, num, 4);
+ HMAC_SHA512_Final(output, &ctx);
+}
+
+bool CKey::Derive(CKey& keyChild, unsigned char ccChild[32], unsigned int nChild, const unsigned char cc[32]) const {
+ assert(IsValid());
+ assert(IsCompressed());
+ unsigned char out[64];
+ LockObject(out);
+ if ((nChild >> 31) == 0) {
+ CPubKey pubkey = GetPubKey();
+ assert(pubkey.begin() + 33 == pubkey.end());
+ BIP32Hash(cc, nChild, *pubkey.begin(), pubkey.begin()+1, out);
+ } else {
+ assert(begin() + 32 == end());
+ BIP32Hash(cc, nChild, 0, begin(), out);
+ }
+ memcpy(ccChild, out+32, 32);
+ bool ret = CECKey::TweakSecret((unsigned char*)keyChild.begin(), begin(), out);
+ UnlockObject(out);
+ keyChild.fCompressed = true;
+ keyChild.fValid = ret;
+ return ret;
+}
+
+bool CPubKey::Derive(CPubKey& pubkeyChild, unsigned char ccChild[32], unsigned int nChild, const unsigned char cc[32]) const {
+ assert(IsValid());
+ assert((nChild >> 31) == 0);
+ assert(begin() + 33 == end());
+ unsigned char out[64];
+ BIP32Hash(cc, nChild, *begin(), begin()+1, out);
+ memcpy(ccChild, out+32, 32);
+ CECKey key;
+ bool ret = key.SetPubKey(*this);
+ ret &= key.TweakPublic(out);
+ key.GetPubKey(pubkeyChild, true);
+ return ret;
+}
+
+bool CExtKey::Derive(CExtKey &out, unsigned int nChild) const {
+ out.nDepth = nDepth + 1;
+ CKeyID id = key.GetPubKey().GetID();
+ memcpy(&out.vchFingerprint[0], &id, 4);
+ out.nChild = nChild;
+ return key.Derive(out.key, out.vchChainCode, nChild, vchChainCode);
+}
+
+void CExtKey::SetMaster(const unsigned char *seed, unsigned int nSeedLen) {
+ static const char hashkey[] = {'B','i','t','c','o','i','n',' ','s','e','e','d'};
+ HMAC_SHA512_CTX ctx;
+ HMAC_SHA512_Init(&ctx, hashkey, sizeof(hashkey));
+ HMAC_SHA512_Update(&ctx, seed, nSeedLen);
+ unsigned char out[64];
+ LockObject(out);
+ HMAC_SHA512_Final(out, &ctx);
+ key.Set(&out[0], &out[32], true);
+ memcpy(vchChainCode, &out[32], 32);
+ UnlockObject(out);
+ nDepth = 0;
+ nChild = 0;
+ memset(vchFingerprint, 0, sizeof(vchFingerprint));
+}
+
+CExtPubKey CExtKey::Neuter() const {
+ CExtPubKey ret;
+ ret.nDepth = nDepth;
+ memcpy(&ret.vchFingerprint[0], &vchFingerprint[0], 4);
+ ret.nChild = nChild;
+ ret.pubkey = key.GetPubKey();
+ memcpy(&ret.vchChainCode[0], &vchChainCode[0], 32);
+ return ret;
+}
+
+void CExtKey::Encode(unsigned char code[74]) const {
+ code[0] = nDepth;
+ memcpy(code+1, vchFingerprint, 4);
+ code[5] = (nChild >> 24) & 0xFF; code[6] = (nChild >> 16) & 0xFF;
+ code[7] = (nChild >> 8) & 0xFF; code[8] = (nChild >> 0) & 0xFF;
+ memcpy(code+9, vchChainCode, 32);
+ code[41] = 0;
+ assert(key.size() == 32);
+ memcpy(code+42, key.begin(), 32);
+}
+
+void CExtKey::Decode(const unsigned char code[74]) {
+ nDepth = code[0];
+ memcpy(vchFingerprint, code+1, 4);
+ nChild = (code[5] << 24) | (code[6] << 16) | (code[7] << 8) | code[8];
+ memcpy(vchChainCode, code+9, 32);
+ key.Set(code+42, code+74, true);
+}
+
+void CExtPubKey::Encode(unsigned char code[74]) const {
+ code[0] = nDepth;
+ memcpy(code+1, vchFingerprint, 4);
+ code[5] = (nChild >> 24) & 0xFF; code[6] = (nChild >> 16) & 0xFF;
+ code[7] = (nChild >> 8) & 0xFF; code[8] = (nChild >> 0) & 0xFF;
+ memcpy(code+9, vchChainCode, 32);
+ assert(pubkey.size() == 33);
+ memcpy(code+41, pubkey.begin(), 33);
+}
+
+void CExtPubKey::Decode(const unsigned char code[74]) {
+ nDepth = code[0];
+ memcpy(vchFingerprint, code+1, 4);
+ nChild = (code[5] << 24) | (code[6] << 16) | (code[7] << 8) | code[8];
+ memcpy(vchChainCode, code+9, 32);
+ pubkey.Set(code+41, code+74);
+}
+
+bool CExtPubKey::Derive(CExtPubKey &out, unsigned int nChild) const {
+ out.nDepth = nDepth + 1;
+ CKeyID id = pubkey.GetID();
+ memcpy(&out.vchFingerprint[0], &id, 4);
+ out.nChild = nChild;
+ return pubkey.Derive(out.pubkey, out.vchChainCode, nChild, vchChainCode);
+}
generated by cgit v1.2.3 (git 2.26.2) at 2024-11-02 00:22:27 +0000