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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2017 The Starwels developers
// Copyright (c) 2017 The Zcash developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#ifndef STARWELS_PUBKEY_H
#define STARWELS_PUBKEY_H
#include <hash.h>
#include <serialize.h>
#include <uint256.h>
#include <stdexcept>
#include <vector>
const unsigned int BIP32_EXTKEY_SIZE = 74;
/** A reference to a CKey: the Hash160 of its serialized public key */
class CKeyID : public uint160
{
public:
CKeyID() : uint160() {}
explicit CKeyID(const uint160& in) : uint160(in) {}
};
typedef uint256 ChainCode;
/** An encapsulated public key. */
class CPubKey
{
public:
/**
* secp256k1:
*/
static const unsigned int PUBLIC_KEY_SIZE = 65;
static const unsigned int COMPRESSED_PUBLIC_KEY_SIZE = 33;
static const unsigned int SIGNATURE_SIZE = 72;
static const unsigned int COMPACT_SIGNATURE_SIZE = 65;
/**
* see www.keylength.com
* script supports up to 75 for single byte push
*/
static_assert(
PUBLIC_KEY_SIZE >= COMPRESSED_PUBLIC_KEY_SIZE,
"COMPRESSED_PUBLIC_KEY_SIZE is larger than PUBLIC_KEY_SIZE");
private:
/**
* Just store the serialized data.
* Its length can very cheaply be computed from the first byte.
*/
unsigned char vch[PUBLIC_KEY_SIZE];
//! Compute the length of a pubkey with a given first byte.
unsigned int static GetLen(unsigned char chHeader)
{
if (chHeader == 2 || chHeader == 3)
return COMPRESSED_PUBLIC_KEY_SIZE;
if (chHeader == 4 || chHeader == 6 || chHeader == 7)
return PUBLIC_KEY_SIZE;
return 0;
}
//! Set this key data to be invalid
void Invalidate()
{
vch[0] = 0xFF;
}
public:
//! Construct an invalid public key.
CPubKey()
{
Invalidate();
}
//! Initialize a public key using begin/end iterators to byte data.
template <typename T>
void Set(const T pbegin, const T pend)
{
int len = pend == pbegin ? 0 : GetLen(pbegin[0]);
if (len && len == (pend - pbegin))
memcpy(vch, (unsigned char*)&pbegin[0], len);
else
Invalidate();
}
//! Construct a public key using begin/end iterators to byte data.
template <typename T>
CPubKey(const T pbegin, const T pend)
{
Set(pbegin, pend);
}
//! Construct a public key from a byte vector.
explicit CPubKey(const std::vector<unsigned char>& _vch)
{
Set(_vch.begin(), _vch.end());
}
//! Simple read-only vector-like interface to the pubkey data.
unsigned int size() const { return GetLen(vch[0]); }
const unsigned char* begin() const { return vch; }
const unsigned char* end() const { return vch + size(); }
const unsigned char& operator[](unsigned int pos) const { return vch[pos]; }
//! Comparator implementation.
friend bool operator==(const CPubKey& a, const CPubKey& b)
{
return a.vch[0] == b.vch[0] &&
memcmp(a.vch, b.vch, a.size()) == 0;
}
friend bool operator!=(const CPubKey& a, const CPubKey& b)
{
return !(a == b);
}
friend bool operator<(const CPubKey& a, const CPubKey& b)
{
return a.vch[0] < b.vch[0] ||
(a.vch[0] == b.vch[0] && memcmp(a.vch, b.vch, a.size()) < 0);
}
//! Implement serialization, as if this was a byte vector.
template <typename Stream>
void Serialize(Stream& s) const
{
unsigned int len = size();
::WriteCompactSize(s, len);
s.write((char*)vch, len);
}
template <typename Stream>
void Unserialize(Stream& s)
{
unsigned int len = ::ReadCompactSize(s);
if (len <= PUBLIC_KEY_SIZE) {
s.read((char*)vch, len);
} else {
// invalid pubkey, skip available data
char dummy;
while (len--)
s.read(&dummy, 1);
Invalidate();
}
}
//! Get the KeyID of this public key (hash of its serialization)
CKeyID GetID() const
{
return CKeyID(Hash160(vch, vch + size()));
}
//! Get the 256-bit hash of this public key.
uint256 GetHash() const
{
return Hash(vch, vch + size());
}
/*
* Check syntactic correctness.
*
* Note that this is consensus critical as CheckSig() calls it!
*/
bool IsValid() const
{
return size() > 0;
}
//! fully validate whether this is a valid public key (more expensive than IsValid())
bool IsFullyValid() const;
//! Check whether this is a compressed public key.
bool IsCompressed() const
{
return size() == COMPRESSED_PUBLIC_KEY_SIZE;
}
/**
* Verify a DER signature (~72 bytes).
* If this public key is not fully valid, the return value will be false.
*/
bool Verify(const uint256& hash, const std::vector<unsigned char>& vchSig) const;
/**
* Check whether a signature is normalized (lower-S).
*/
static bool CheckLowS(const std::vector<unsigned char>& vchSig);
//! Recover a public key from a compact signature.
bool RecoverCompact(const uint256& hash, const std::vector<unsigned char>& vchSig);
//! Turn this public key into an uncompressed public key.
bool Decompress();
//! Derive BIP32 child pubkey.
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;
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], sizeof(vchFingerprint)) == 0 &&
a.nChild == b.nChild &&
a.chaincode == b.chaincode &&
a.pubkey == b.pubkey;
}
void Encode(unsigned char code[BIP32_EXTKEY_SIZE]) const;
void Decode(const unsigned char code[BIP32_EXTKEY_SIZE]);
bool Derive(CExtPubKey& out, unsigned int nChild) const;
void Serialize(CSizeComputer& s) const
{
// Optimized implementation for ::GetSerializeSize that avoids copying.
s.seek(BIP32_EXTKEY_SIZE + 1); // add one byte for the size (compact int)
}
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);
}
};
/** Users of this module must hold an ECCVerifyHandle. The constructor and
* destructor of these are not allowed to run in parallel, though. */
class ECCVerifyHandle
{
static int refcount;
public:
ECCVerifyHandle();
~ECCVerifyHandle();
};
#endif // STARWELS_PUBKEY_H