Ensure export finalization edge case

[VerusCoin.git] / src / cc / MofN.cpp

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#include "CCMofN.h"

/*
 The idea of MofN CC is to allow non-interactive multisig, preferably in a cross chain compatible way, ie. for actual bitcoin multisig.
 
 full redeemscript in an initial tx with opreturn
 ability to post partial signatures and construct a full transaction from M such partial signatures
 a new transaction would refer to the initialtx and other partial would refer to both
 
 There is no need for a CC contract to use it for normal multisig as normal multisig transactions are already supported.
 
 In order to take advantage of CC powers, we can create a more powerful multisig using shamir's secret MofN (up to 255) algo to allow spends. Using the same non-interactive partial signing is possible. also, in addition to spending, data payload can have additional data that is also revealed when the funds are spent.
 
 rpc calls needed:
 1) create msig address (normal or shamir)
 2) post payment with partial sig
 3) add partial sig to 2)
 4) combine and submit M partial sigs
 
*/

// start of consensus code

int64_t IsMofNvout(struct CCcontract_info *cp,const CTransaction& tx,int32_t v)
{
    char destaddr[64];
    if ( tx.vout[v].scriptPubKey.IsPayToCryptoCondition() != 0 )
    {
        if ( Getscriptaddress(destaddr,tx.vout[v].scriptPubKey) > 0 && strcmp(destaddr,cp->unspendableCCaddr) == 0 )
            return(tx.vout[v].nValue);
    }
    return(0);
}

bool MofNExactAmounts(struct CCcontract_info *cp,Eval* eval,const CTransaction &tx,int32_t minage,uint64_t txfee)
{
    static uint256 zerohash;
    CTransaction vinTx; uint256 hashBlock,activehash; int32_t i,numvins,numvouts; int64_t inputs=0,outputs=0,assetoshis;
    numvins = tx.vin.size();
    numvouts = tx.vout.size();
    for (i=0; i<numvins; i++)
    {
        //fprintf(stderr,"vini.%d\n",i);
        if ( (*cp->ismyvin)(tx.vin[i].scriptSig) != 0 )
        {
            //fprintf(stderr,"vini.%d check mempool\n",i);
            if ( eval->GetTxUnconfirmed(tx.vin[i].prevout.hash,vinTx,hashBlock) == 0 )
                return eval->Invalid("cant find vinTx");
            else
            {
                //fprintf(stderr,"vini.%d check hash and vout\n",i);
                if ( hashBlock == zerohash )
                    return eval->Invalid("cant MofN from mempool");
                if ( (assetoshis= IsMofNvout(cp,vinTx,tx.vin[i].prevout.n)) != 0 )
                    inputs += assetoshis;
            }
        }
    }
    for (i=0; i<numvouts; i++)
    {
        //fprintf(stderr,"i.%d of numvouts.%d\n",i,numvouts);
        if ( (assetoshis= IsMofNvout(cp,tx,i)) != 0 )
            outputs += assetoshis;
    }
    if ( inputs != outputs+txfee )
    {
        fprintf(stderr,"inputs %llu vs outputs %llu\n",(long long)inputs,(long long)outputs);
        return eval->Invalid("mismatched inputs != outputs + txfee");
    }
    else return(true);
}

bool MofNValidate(struct CCcontract_info *cp,Eval* eval,const CTransaction &tx, uint32_t nIn, bool fulfilled)
{
    int32_t numvins,numvouts,preventCCvins,preventCCvouts,i,numblocks; bool retval; uint256 txid; uint8_t hash[32]; char str[65],destaddr[64];
    return(false);
    std::vector<std::pair<CAddressIndexKey, CAmount> > txids;
    numvins = tx.vin.size();
    numvouts = tx.vout.size();
    preventCCvins = preventCCvouts = -1;
    if ( numvouts < 1 )
        return eval->Invalid("no vouts");
    else
    {
        for (i=0; i<numvins; i++)
        {
            if ( IsCCInput(tx.vin[0].scriptSig) == 0 )
            {
                return eval->Invalid("illegal normal vini");
            }
        }
        //fprintf(stderr,"check amounts\n");
        if ( MofNExactAmounts(cp,eval,tx,1,10000) == false )
        {
            fprintf(stderr,"mofnget invalid amount\n");
            return false;
        }
        else
        {
            txid = tx.GetHash();
            memcpy(hash,&txid,sizeof(hash));
            retval = PreventCC(eval,tx,preventCCvins,numvins,preventCCvouts,numvouts);
            if ( retval != 0 )
                fprintf(stderr,"mofnget validated\n");
            else fprintf(stderr,"mofnget invalid\n");
            return(retval);
        }
    }
}
// end of consensus code

// helper functions for rpc calls in rpcwallet.cpp

int64_t AddMofNInputs(struct CCcontract_info *cp,CMutableTransaction &mtx,CPubKey pk,int64_t total,int32_t maxinputs)
{
    char coinaddr[64]; int64_t nValue,price,totalinputs = 0; uint256 txid,hashBlock; std::vector<uint8_t> origpubkey; CTransaction vintx; int32_t vout,n = 0;
    std::vector<std::pair<CAddressUnspentKey, CAddressUnspentValue> > unspentOutputs;
    GetCCaddress(cp,coinaddr,pk);
    SetCCunspents(unspentOutputs,coinaddr);
    for (std::vector<std::pair<CAddressUnspentKey, CAddressUnspentValue> >::const_iterator it=unspentOutputs.begin(); it!=unspentOutputs.end(); it++)
    {
        txid = it->first.txhash;
        vout = (int32_t)it->first.index;
        // no need to prevent dup
        if ( GetTransaction(txid,vintx,hashBlock,false) != 0 )
        {
            if ( (nValue= IsMofNvout(cp,vintx,vout)) > 1000000 && myIsutxo_spentinmempool(txid,vout) == 0 )
            {
                if ( total != 0 && maxinputs != 0 )
                    mtx.vin.push_back(CTxIn(txid,vout,CScript()));
                nValue = it->second.satoshis;
                totalinputs += nValue;
                n++;
                if ( (total > 0 && totalinputs >= total) || (maxinputs > 0 && n >= maxinputs) )
                    break;
            }
        }
    }
    return(totalinputs);
}

std::string MofNGet(uint64_t txfee,int64_t nValue)
{
    CMutableTransaction mtx,tmpmtx; CPubKey mypk,mofnpk; int64_t inputs,CCchange=0; struct CCcontract_info *cp,C; std::string rawhex; uint32_t j; int32_t i,len; uint8_t buf[32768]; bits256 hash;
    cp = CCinit(&C,EVAL_MOFN);
    if ( txfee == 0 )
        txfee = 10000;
    mofnpk = GetUnspendable(cp,0);
    mypk = pubkey2pk(Mypubkey());
    if ( (inputs= AddMofNInputs(cp,mtx,mofnpk,nValue+txfee,60)) > 0 )
    {
        if ( inputs > nValue )
            CCchange = (inputs - nValue - txfee);
        if ( CCchange != 0 )
            mtx.vout.push_back(MakeCC1vout(EVAL_MOFN,CCchange,mofnpk));
        mtx.vout.push_back(CTxOut(nValue,CScript() << ParseHex(HexStr(mypk)) << OP_CHECKSIG));
        fprintf(stderr,"start at %u\n",(uint32_t)time(NULL));
        j = rand() & 0xfffffff;
        for (i=0; i<1000000; i++,j++)
        {
            tmpmtx = mtx;
            rawhex = FinalizeCCTx(-1LL,cp,tmpmtx,mypk,txfee,CScript() << OP_RETURN << E_MARSHAL(ss << (uint8_t)EVAL_MOFN << (uint8_t)'G' << j));
            if ( (len= (int32_t)rawhex.size()) > 0 && len < 65536 )
            {
                len >>= 1;
                decode_hex(buf,len,(char *)rawhex.c_str());
                hash = bits256_doublesha256(0,buf,len);
                if ( (hash.bytes[0] & 0xff) == 0 && (hash.bytes[31] & 0xff) == 0 )
                {
                    fprintf(stderr,"found valid txid after %d iterations %u\n",i,(uint32_t)time(NULL));
                    return(rawhex);
                }
                //fprintf(stderr,"%02x%02x ",hash.bytes[0],hash.bytes[31]);
            }
        }
        fprintf(stderr,"couldnt generate valid txid %u\n",(uint32_t)time(NULL));
        return("");
    } else fprintf(stderr,"cant find mofn inputs\n");
    return("");
}

std::string MofNFund(uint64_t txfee,int64_t funds)
{
    CMutableTransaction mtx; CPubKey mypk,mofnpk; CScript opret; struct CCcontract_info *cp,C;
    cp = CCinit(&C,EVAL_MOFN);
    if ( txfee == 0 )
        txfee = 10000;
    mypk = pubkey2pk(Mypubkey());
    mofnpk = GetUnspendable(cp,0);
    if ( AddNormalinputs(mtx,mypk,funds+txfee,64) > 0 )
    {
        mtx.vout.push_back(MakeCC1vout(EVAL_MOFN,funds,mofnpk));
        return(FinalizeCCTx(0,cp,mtx,mypk,txfee,opret));
    }
    return("");
}

UniValue MofNInfo()
{
    UniValue result(UniValue::VOBJ); char numstr[64];
    CMutableTransaction mtx; CPubKey mofnpk; struct CCcontract_info *cp,C; int64_t funding;
    result.push_back(Pair("result","success"));
    result.push_back(Pair("name","MofN"));
    cp = CCinit(&C,EVAL_MOFN);
    mofnpk = GetUnspendable(cp,0);
    funding = AddMofNInputs(cp,mtx,mofnpk,0,0);
    sprintf(numstr,"%.8f",(double)funding/COIN);
    result.push_back(Pair("funding",numstr));
    return(result);
}