PAK enforcement via standardness, drop multi-op_return restriction

src/chainparams.cpp

@@ -153,6 +153,7 @@ public:
         consensus.genesis_subsidy = 50*COIN;
         consensus.connect_genesis_outputs = false;
         anyonecanspend_aremine = false;
+        enforce_pak = false;
 
         /**
          * The message start string is designed to be unlikely to occur in normal data.
@@ -271,6 +272,7 @@ public:
         consensus.genesis_subsidy = 50*COIN;
         consensus.connect_genesis_outputs = false;
         anyonecanspend_aremine = false;
+        enforce_pak = false;
 
         pchMessageStart[0] = 0x0b;
         pchMessageStart[1] = 0x11;
@@ -364,6 +366,7 @@ public:
         consensus.genesis_subsidy = 50*COIN;
         consensus.connect_genesis_outputs = false;
         anyonecanspend_aremine = false;
+        enforce_pak = false;
 
         pchMessageStart[0] = 0xfa;
         pchMessageStart[1] = 0xbf;
@@ -541,6 +544,9 @@ class CCustomParams : public CRegTestParams {
         anyonecanspend_aremine = args.GetBoolArg("-anyonecanspendaremine", true);
 
         consensus.has_parent_chain = args.GetBoolArg("-con_has_parent_chain", true);
+
+        enforce_pak = args.GetBoolArg("-enforce_pak", false);
+
         // bitcoin regtest is the parent chain by default
         parentGenesisBlockHash = uint256S(args.GetArg("-parentgenesisblockhash", "0f9188f13cb7b2c71f2a335e3a4fc328bf5beb436012afca590b1a11466e2206"));
         // Either it has a parent chain or not

src/chainparams.h

@@ -87,6 +87,7 @@ public:
     const uint256 ParentGenesisBlockHash() const { return parentGenesisBlockHash; }
     bool anyonecanspend_aremine;
     const std::string& ParentBech32HRP() const { return parent_bech32_hrp; }
+    bool GetEnforcePak() const { return enforce_pak; }
 
 protected:
     CChainParams() {}
@@ -111,6 +112,7 @@ protected:
     // ELEMENTS extra fields:
     uint256 parentGenesisBlockHash;
     std::string parent_bech32_hrp;
+    bool enforce_pak;
 };
 
 /**

src/chainparamsbase.cpp

@@ -38,6 +38,7 @@ void SetupChainParamsBaseOptions()
     gArgs.AddArg("-con_parent_chain_signblockscript", "Whether parent chain uses pow or signed blocks. If the parent chain uses signed blocks, the challenge (scriptPubKey) script. If not, an empty string. (default: empty script [ie parent uses pow])", false, OptionsCategory::CHAINPARAMS);
 
     gArgs.AddArg("-fedpegscript", "The script for the federated peg.", false, OptionsCategory::CHAINPARAMS);
+    gArgs.AddArg("-enforce_pak", "Causes standardness checks to enforce Pegout Authorization Key(PAK) validation, and miner to include PAK commitments when configured. Can not be set when acceptnonstdtx is set to true.", false, OptionsCategory::ELEMENTS);
 }
 
 static std::unique_ptr<CBaseChainParams> globalChainBaseParams;

src/policy/policy.cpp

@@ -14,6 +14,7 @@
 #include <tinyformat.h>
 #include <util.h>
 #include <utilstrencodings.h>
+#include <chainparams.h> // Peg-out enforcement
 
 
 CAmount GetDustThreshold(const CTxOut& txout, const CFeeRate& dustRelayFeeIn)
@@ -61,6 +62,7 @@ bool IsStandard(const CScript& scriptPubKey, txnouttype& whichType)
     if (!Solver(scriptPubKey, whichType, vSolutions))
         return false;
 
+    CChainParams params = Params();
     if (whichType == TX_MULTISIG)
     {
         unsigned char m = vSolutions.front()[0];
@@ -70,6 +72,10 @@ bool IsStandard(const CScript& scriptPubKey, txnouttype& whichType)
             return false;
         if (m < 1 || m > n)
             return false;
+    } else if (whichType == TX_NULL_DATA && params.GetEnforcePak() &&
+            scriptPubKey.IsPegoutScript(Params().ParentGenesisBlockHash()) ) {
+        // If we're enforcing pak let through larger peg-out scripts
+        return true;
     } else if (whichType == TX_NULL_DATA &&
                (!fAcceptDatacarrier || scriptPubKey.size() > nMaxDatacarrierBytes))
           return false;
@@ -113,6 +119,7 @@ bool IsStandardTx(const CTransaction& tx, std::string& reason)
         }
     }
 
+    CChainParams params = Params();
     unsigned int nDataOut = 0;
     txnouttype whichType;
     for (const CTxOut& txout : tx.vout) {
@@ -121,9 +128,18 @@ bool IsStandardTx(const CTransaction& tx, std::string& reason)
             return false;
         }
 
-        if (whichType == TX_NULL_DATA)
+        if (whichType == TX_NULL_DATA) {
+        }
+        if (whichType == TX_NULL_DATA) {
             nDataOut++;
-        else if ((whichType == TX_MULTISIG) && (!fIsBareMultisigStd)) {
+            if (params.GetEnforcePak() &&
+                    txout.scriptPubKey.IsPegoutScript(params.ParentGenesisBlockHash()) &&
+                (!ScriptHasValidPAKProof(txout.scriptPubKey, params.ParentGenesisBlockHash()))) {
+                // TODO(rebase) CT/CA check for asset type
+                reason = "invalid-pegout-proof";
+                return false;
+            }
+        } else if ((whichType == TX_MULTISIG) && (!fIsBareMultisigStd)) {
             reason = "bare-multisig";
             return false;
         } else if (IsDust(txout, ::dustRelayFee)) {