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);
 }