// Copyright (c) 2016, Monero Research Labs
//
// Author: Shen Noether <shen.noether@gmx.com>
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification, are
// permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this list of
// conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice, this list
// of conditions and the following disclaimer in the documentation and/or other
// materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its contributors may be
// used to endorse or promote products derived from this software without specific
// prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#pragma once
//#define DBG
#ifndef RCTSIGS_H
#define RCTSIGS_H
#include <cstddef>
#include <mutex>
#include <vector>
#include <tuple>
#include "crypto/generic-ops.h"
extern "C" {
#include "crypto/random.h"
#include "crypto/keccak.h"
}
#include "crypto/crypto.h"
#include "rctTypes.h"
#include "rctOps.h"
//Define this flag when debugging to get additional info on the console
#ifdef DBG
#define DP(x) dp(x)
#else
#define DP(x)
#endif
using namespace std;
using namespace crypto;
namespace rct {
//Schnorr Non-linkable
//Gen Gives a signature (L1, s1, s2) proving that the sender knows "x" such that xG = one of P1 or P2
//Ver Verifies that signer knows an "x" such that xG = one of P1 or P2
//These are called in the below ASNL sig generation
void GenSchnorrNonLinkable(key & L1, key & s1, key & s2, const key & x, const key & P1, const key & P2, int index);
bool VerSchnorrNonLinkable(const key & P1, const key & P2, const key & L1, const key & s1, const key & s2);
//Aggregate Schnorr Non-linkable Ring Signature (ASNL)
// c.f. http://eprint.iacr.org/2015/1098 section 5.
// These are used in range proofs (alternatively Borromean could be used)
// Gen gives a signature which proves the signer knows, for each i,
// an x[i] such that x[i]G = one of P1[i] or P2[i]
// Ver Verifies the signer knows a key for one of P1[i], P2[i] at each i
asnlSig GenASNL(key64 x, key64 P1, key64 P2, bits indices);
bool VerASNL(const key64 P1, const key64 P2, const asnlSig &as);
//Multilayered Spontaneous Anonymous Group Signatures (MLSAG signatures)
//These are aka MG signatutes in earlier drafts of the ring ct paper
// c.f. http://eprint.iacr.org/2015/1098 section 2.
// keyImageV just does I[i] = xx[i] * HashToPoint(xx[i] * G) for each i
// Gen creates a signature which proves that for some column in the keymatrix "pk"
// the signer knows a secret key for each row in that column
// Ver verifies that the MG sig was created correctly
keyV keyImageV(const keyV &xx);
mgSig MLSAG_Gen(key message, const keyM & pk, const keyV & xx, const unsigned int index, size_t dsRows);
bool MLSAG_Ver(key message, const keyM &pk, const mgSig &sig, size_t dsRows);
//mgSig MLSAG_Gen_Old(const keyM & pk, const keyV & xx, const int index);
//proveRange and verRange
//proveRange gives C, and mask such that \sumCi = C
// c.f. http://eprint.iacr.org/2015/1098 section 5.1
// and Ci is a commitment to either 0 or 2^i, i=0,...,63
// thus this proves that "amount" is in [0, 2^64]
// mask is a such that C = aG + bH, and b = amount
//verRange verifies that \sum Ci = C and that each Ci is a commitment to 0 or 2^i
rangeSig proveRange(key & C, key & mask, const xmr_amount & amount);
bool verRange(const key & C, const rangeSig & as);
//Ring-ct MG sigs
//Prove:
// c.f. http://eprint.iacr.org/2015/1098 section 4. definition 10.
// This does the MG sig on the "dest" part of the given key matrix, and
// the last row is the sum of input commitments from that column - sum output commitments
// this shows that sum inputs = sum outputs
//Ver:
// verifies the above sig is created corretly
mgSig proveRctMG(const ctkeyM & pubs, const ctkeyV & inSk, const keyV &outMasks, const ctkeyV & outPk, unsigned int index, key txnFee, const key &message);
mgSig proveRctMGSimple(const key & message, const ctkeyV & pubs, const ctkey & inSk, const key &a , const key &Cout, unsigned int index);
bool verRctMG(mgSig mg, const ctkeyM & pubs, const ctkeyV & outPk, key txnFee, const key &message);
bool verRctMGSimple(const key &message, const mgSig &mg, const ctkeyV & pubs, const key & C);
//These functions get keys from blockchain
//replace these when connecting blockchain
//getKeyFromBlockchain grabs a key from the blockchain at "reference_index" to mix with
//populateFromBlockchain creates a keymatrix with "mixin" columns and one of the columns is inPk
// the return value are the key matrix, and the index where inPk was put (random).
void getKeyFromBlockchain(ctkey & a, size_t reference_index);
tuple<ctkeyM, xmr_amount> populateFromBlockchain(ctkeyV inPk, int mixin);
//RingCT protocol
//genRct:
// creates an rctSig with all data necessary to verify the rangeProofs and that the signer owns one of the
// columns that are claimed as inputs, and that the sum of inputs = sum of outputs.
// Also contains masked "amount" and "mask" so the receiver can see how much they received
//verRct:
// verifies that all signatures (rangeProogs, MG sig, sum inputs = outputs) are correct
//decodeRct: (c.f. http://eprint.iacr.org/2015/1098 section 5.1.1)
// uses the attached ecdh info to find the amounts represented by each output commitment
// must know the destination private key to find the correct amount, else will return a random number
rctSig genRct(const key &message, const ctkeyV & inSk, const keyV & destinations, const vector<xmr_amount> & amounts, const ctkeyM &mixRing, const keyV &amount_keys, unsigned int index, ctkeyV &outSk);
rctSig genRct(const key &message, const ctkeyV & inSk, const ctkeyV & inPk, const keyV & destinations, const vector<xmr_amount> & amounts, const keyV &amount_keys, const int mixin);
rctSig genRctSimple(const key & message, const ctkeyV & inSk, const ctkeyV & inPk, const keyV & destinations, const vector<xmr_amount> & inamounts, const vector<xmr_amount> & outamounts, const keyV &amount_keys, xmr_amount txnFee, unsigned int mixin);
rctSig genRctSimple(const key & message, const ctkeyV & inSk, const keyV & destinations, const vector<xmr_amount> & inamounts, const vector<xmr_amount> & outamounts, xmr_amount txnFee, const ctkeyM & mixRing, const keyV &amount_keys, const std::vector<unsigned int> & index, ctkeyV &outSk);
bool verRct(const rctSig & rv);
bool verRctSimple(const rctSig & rv);
xmr_amount decodeRct(const rctSig & rv, const key & sk, unsigned int i, key & mask);
xmr_amount decodeRctFromSharedSecret(const rctSig & rv, const key & sk, unsigned int i, key & mask);
xmr_amount decodeRct(const rctSig & rv, const key & sk, unsigned int i);
xmr_amount decodeRctSimpleFromSharedSecret(const rctSig & rv, const key & sk, unsigned int i, key & mask);
xmr_amount decodeRctSimple(const rctSig & rv, const key & sk, unsigned int i, key & mask);
xmr_amount decodeRctSimple(const rctSig & rv, const key & sk, unsigned int i);
}
#endif /* RCTSIGS_H */
