chaincodes: abstract away more chaincode behavior

[squashme] replace struct CCainCode with a typedef uint256 ChainCode

src/hash.cpp

@@ -5,6 +5,7 @@
 #include "hash.h"
 #include "crypto/common.h"
 #include "crypto/hmac_sha512.h"
+#include "pubkey.h"
 
 
 inline uint32_t ROTL32(uint32_t x, int8_t r)
@@ -71,15 +72,12 @@ unsigned int MurmurHash3(unsigned int nHashSeed, const std::vector<unsigned char
     return h1;
 }
 
-void BIP32Hash(const unsigned char chainCode[32], unsigned int nChild, unsigned char header, const unsigned char data[32], unsigned char output[64])
+void BIP32Hash(const ChainCode &chainCode, 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;
-    CHMAC_SHA512(chainCode, 32).Write(&header, 1)
-                               .Write(data, 32)
-                               .Write(num, 4)
-                               .Finalize(output);
+    CHMAC_SHA512(chainCode.begin(), chainCode.size()).Write(&header, 1).Write(data, 32).Write(num, 4).Finalize(output);
 }

src/hash.h

@@ -14,6 +14,8 @@
 
 #include <vector>
 
+typedef uint256 ChainCode;
+
 /** A hasher class for Bitcoin's 256-bit hash (double SHA-256). */
 class CHash256 {
 private:
@@ -159,6 +161,6 @@ uint256 SerializeHash(const T& obj, int nType=SER_GETHASH, int nVersion=PROTOCOL
 
 unsigned int MurmurHash3(unsigned int nHashSeed, const std::vector<unsigned char>& vDataToHash);
 
-void BIP32Hash(const unsigned char chainCode[32], unsigned int nChild, unsigned char header, const unsigned char data[32], unsigned char output[64]);
+void BIP32Hash(const ChainCode &chainCode, unsigned int nChild, unsigned char header, const unsigned char data[32], unsigned char output[64]);
 
 #endif // BITCOIN_HASH_H

src/key.cpp

@@ -125,7 +125,7 @@ bool CKey::Load(CPrivKey &privkey, CPubKey &vchPubKey, bool fSkipCheck=false) {
     return VerifyPubKey(vchPubKey);
 }
 
-bool CKey::Derive(CKey& keyChild, unsigned char ccChild[32], unsigned int nChild, const unsigned char cc[32]) const {
+bool CKey::Derive(CKey& keyChild, ChainCode &ccChild, unsigned int nChild, const ChainCode& cc) const {
     assert(IsValid());
     assert(IsCompressed());
     unsigned char out[64];
@@ -138,7 +138,7 @@ bool CKey::Derive(CKey& keyChild, unsigned char ccChild[32], unsigned int nChild
         assert(begin() + 32 == end());
         BIP32Hash(cc, nChild, 0, begin(), out);
     }
-    memcpy(ccChild, out+32, 32);
+    memcpy(ccChild.begin(), out+32, 32);
     memcpy((unsigned char*)keyChild.begin(), begin(), 32);
     bool ret = secp256k1_ec_privkey_tweak_add((unsigned char*)keyChild.begin(), out);
     UnlockObject(out);
@@ -152,7 +152,7 @@ bool CExtKey::Derive(CExtKey &out, unsigned int nChild) const {
     CKeyID id = key.GetPubKey().GetID();
     memcpy(&out.vchFingerprint[0], &id, 4);
     out.nChild = nChild;
-    return key.Derive(out.key, out.chaincode.data, nChild, chaincode.data);
+    return key.Derive(out.key, out.chaincode, nChild, chaincode);
 }
 
 void CExtKey::SetMaster(const unsigned char *seed, unsigned int nSeedLen) {
@@ -161,7 +161,7 @@ void CExtKey::SetMaster(const unsigned char *seed, unsigned int nSeedLen) {
     LockObject(out);
     CHMAC_SHA512(hashkey, sizeof(hashkey)).Write(seed, nSeedLen).Finalize(out);
     key.Set(&out[0], &out[32], true);
-    memcpy(chaincode.data, &out[32], 32);
+    memcpy(chaincode.begin(), &out[32], 32);
     UnlockObject(out);
     nDepth = 0;
     nChild = 0;
@@ -174,7 +174,7 @@ CExtPubKey CExtKey::Neuter() const {
     memcpy(&ret.vchFingerprint[0], &vchFingerprint[0], 4);
     ret.nChild = nChild;
     ret.pubkey = key.GetPubKey();
-    memcpy(&ret.chaincode.data[0], &chaincode.data[0], 32);
+    ret.chaincode = chaincode;
     return ret;
 }
 
@@ -183,7 +183,7 @@ void CExtKey::Encode(unsigned char code[74]) const {
     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, chaincode.data, 32);
+    memcpy(code+9, chaincode.begin(), 32);
     code[41] = 0;
     assert(key.size() == 32);
     memcpy(code+42, key.begin(), 32);
@@ -193,7 +193,7 @@ 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(chaincode.data, code+9, 32);
+    memcpy(chaincode.begin(), code+9, 32);
     key.Set(code+42, code+74, true);
 }
 

src/key.h

@@ -136,7 +136,7 @@ public:
     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;
+    bool Derive(CKey& keyChild, ChainCode &ccChild, unsigned int nChild, const ChainCode& cc) const;
 
     /**
      * Verify thoroughly whether a private key and a public key match.
@@ -155,13 +155,13 @@ struct CExtKey {
     unsigned char nDepth;
     unsigned char vchFingerprint[4];
     unsigned int nChild;
-    CChainCode chaincode;
+    ChainCode chaincode;
     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.chaincode.data[0], &b.chaincode.data[0], 32) == 0 && a.key == b.key;
+               a.chaincode == b.chaincode && a.key == b.key;
     }
 
     void Encode(unsigned char code[74]) const;

src/pubkey.cpp

@@ -54,13 +54,13 @@ bool CPubKey::Decompress() {
     return true;
 }
 
-bool CPubKey::Derive(CPubKey& pubkeyChild, unsigned char ccChild[32], unsigned int nChild, const unsigned char cc[32]) const {
+bool CPubKey::Derive(CPubKey& pubkeyChild, ChainCode &ccChild, unsigned int nChild, const ChainCode& cc) 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);
+    memcpy(ccChild.begin(), out+32, 32);
     CECKey key;
     bool ret = key.SetPubKey(begin(), size());
     ret &= key.TweakPublic(out);
@@ -75,7 +75,7 @@ void CExtPubKey::Encode(unsigned char code[74]) const {
     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, chaincode.data, 32);
+    memcpy(code+9, chaincode.begin(), 32);
     assert(pubkey.size() == 33);
     memcpy(code+41, pubkey.begin(), 33);
 }
@@ -84,7 +84,7 @@ 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(chaincode.data, code+9, 32);
+    memcpy(chaincode.begin(), code+9, 32);
     pubkey.Set(code+41, code+74);
 }
 
@@ -93,5 +93,5 @@ bool CExtPubKey::Derive(CExtPubKey &out, unsigned int nChild) const {
     CKeyID id = pubkey.GetID();
     memcpy(&out.vchFingerprint[0], &id, 4);
     out.nChild = nChild;
-    return pubkey.Derive(out.pubkey, out.chaincode.data, nChild, chaincode.data);
+    return pubkey.Derive(out.pubkey, out.chaincode, nChild, chaincode);
 }

src/pubkey.h

@@ -31,35 +31,7 @@ public:
     CKeyID(const uint160& in) : uint160(in) {}
 };
 
-struct CChainCode
-{
-    unsigned char data[32];
-    
-    void SetNull()
-    {
-        memset(data, 0, sizeof(data));
-    }
-    
-    CChainCode()
-    {
-        SetNull();
-    }
-    
-    bool IsNull() const
-    {
-        for (int i=0; i<32; i++)
-            if (data[i])
-                return false;
-        return true;
-    }
-    
-    ADD_SERIALIZE_METHODS;
-    
-    template <typename Stream, typename Operation>
-    inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) {
-        READWRITE(FLATDATA(data));
-    }
-};
+typedef uint256 ChainCode;
 
 /** An encapsulated public key. */
 class CPubKey
@@ -212,20 +184,20 @@ public:
     bool Decompress();
 
     //! Derive BIP32 child pubkey.
-    bool Derive(CPubKey& pubkeyChild, unsigned char ccChild[32], unsigned int nChild, const unsigned char cc[32]) const;
+    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;
-    CChainCode chaincode;
+    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], 4) == 0 && a.nChild == b.nChild &&
-               memcmp(&a.chaincode.data[0], &b.chaincode.data[0], 32) == 0 && a.pubkey == b.pubkey;
+               a.chaincode == b.chaincode && a.pubkey == b.pubkey;
     }
 
     void Encode(unsigned char code[74]) const;