text: // Copyright (c) 2009-2010 Satoshi Nakamoto
  // Copyright (c) 2009-2016 The Schezuancoin Core developers
  // Distributed under the MIT software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #ifndef SCHEZUANCOIN_KEY_H
  #define SCHEZUANCOIN_KEY_H
  
  #include "pubkey.h"
  #include "serialize.h"
  #include "support/allocators/secure.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
   */
  
  /**
   * 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
      std::vector<unsigned char, secure_allocator<unsigned char> > keydata;
  
      //! Check whether the 32-byte array pointed to by vch is valid keydata.
      bool static Check(const unsigned char* vch);
  
  public:
      //! Construct an invalid private key.
      CKey() : fValid(false), fCompressed(false)
      {
          // Important: vch must be 32 bytes in length to not break serialization
          keydata.resize(32);
      }
  
      friend bool operator==(const CKey& a, const CKey& b)
      {
          return a.fCompressed == b.fCompressed &&
              a.size() == b.size() &&
              memcmp(a.keydata.data(), b.keydata.data(), 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 (size_t(pend - pbegin) != keydata.size()) {
              fValid = false;
          } else if (Check(&pbegin[0])) {
              memcpy(keydata.data(), (unsigned char*)&pbegin[0], keydata.size());
              fValid = true;
              fCompressed = fCompressedIn;
          } else {
              fValid = false;
          }
      }
  
      //! Simple read-only vector-like interface.
      unsigned int size() const { return (fValid ? keydata.size() : 0); }
      const unsigned char* begin() const { return keydata.data(); }
      const unsigned char* end() const { return keydata.data() + 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; }
  
      //! 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.
       * The test_case parameter tweaks the deterministic nonce.
       */
      bool Sign(const uint256& hash, std::vector<unsigned char>& vchSig, uint32_t test_case = 0) 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, ChainCode &ccChild, unsigned int nChild, const ChainCode& cc) const;
  
      /**
       * Verify thoroughly whether a private key and a public key match.
       * This is done using a different mechanism than just regenerating it.
       */
      bool VerifyPubKey(const CPubKey& vchPubKey) const;
  
      //! Load private key and check that public key matches.
      bool Load(CPrivKey& privkey, CPubKey& vchPubKey, bool fSkipCheck);
  };
  
  struct CExtKey {
      unsigned char nDepth;
      unsigned char vchFingerprint[4];
      unsigned int nChild;
      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], sizeof(vchFingerprint)) == 0 &&
              a.nChild == b.nChild &&
              a.chaincode == b.chaincode &&
              a.key == b.key;
      }
  
      void Encode(unsigned char code[BIP32_EXTKEY_SIZE]) const;
      void Decode(const unsigned char code[BIP32_EXTKEY_SIZE]);
      bool Derive(CExtKey& out, unsigned int nChild) const;
      CExtPubKey Neuter() const;
      void SetMaster(const unsigned char* seed, unsigned int nSeedLen);
      template <typename Stream>
      void Serialize(Stream& s) const
      {
          unsigned int len = BIP32_EXTKEY_SIZE;
          ::WriteCompactSize(s, len);
          unsigned char code[BIP32_EXTKEY_SIZE];
          Encode(code);
          s.write((const char *)&code[0], len);
      }
      template <typename Stream>
      void Unserialize(Stream& s)
      {
          unsigned int len = ::ReadCompactSize(s);
          unsigned char code[BIP32_EXTKEY_SIZE];
          if (len != BIP32_EXTKEY_SIZE)
              throw std::runtime_error("Invalid extended key size\n");
          s.read((char *)&code[0], len);
          Decode(code);
      }
  };
  
  /** Initialize the elliptic curve support. May not be called twice without calling ECC_Stop first. */
  void ECC_Start(void);
  
  /** Deinitialize the elliptic curve support. No-op if ECC_Start wasn't called first. */
  void ECC_Stop(void);
  
  /** Check that required EC support is available at runtime. */
  bool ECC_InitSanityCheck(void);
  
  #endif // SCHEZUANCOIN_KEY_H
  