Merge #18267: BIP-325: Signet [consensus]

8258c4c0076bb5f27efdc117a04b27fcd6dd00b2 test: some sanity checks for consensus logic (Anthony Towns)
e47ad375bf17557f805bd206e789b8db78c6338a test: basic signet tests (Karl-Johan Alm)
4c189abdc452f08dfa758564b5381bc78c42d481 test: add small signet fuzzer (practicalswift)
ec9b25d046793be50da1c11ba61d1b4b13b295b0 test: signet network selection tests (Karl-Johan Alm)
3efe298dccb248f25d6b01ab6a80b1cd6c9e1a1e signet: hard-coded parameters for Signet Global Network VI (2020-09-07) (Karl-Johan Alm)
c7898bca4e1ccbc6edafd3b72eaf80df38e3af32 qt: update QT to support signet network (Karl-Johan Alm)
a8de47a1c9033fac3355590f1fe2158a95011bb3 consensus: add signet validation (Karl-Johan Alm)
e8990f121405af8cd539b904ef082439261e6c93 add signet chain and accompanying parameters (Karl-Johan Alm)
404682b7cdb54494e7c98f0ba0cac8b51f379750 add signet basic support (signet.cpp) (Karl-Johan Alm)
a2147d7dadec1febcd9c2b8ebbbf78dce6d0556b validation: move GetWitnessCommitmentIndex to consensus/validation (Karl-Johan Alm)

Pull request description:

  This PR is a part of BIP-325 (https://github.com/bitcoin/bips/blob/master/bip-0325.mediawiki), and is a sub-PR of #16411.

  * Signet consensus (this)
  * Signet RPC tools (pending)
  * Signet utility scripts (contrib/signet) (pending)

ACKs for top commit:
  jonatack:
    re-ACK 8258c4c0076bb5f27efdc117a04b27fcd6dd00b per `git diff dbeea65 8258c4c`, only change since last review is updated `-signet*` config option naming.
  fjahr:
    re-ACK 8258c4c
  laanwj:
    ACK 8258c4c0076bb5f27efdc117a04b27fcd6dd00b2
  MarcoFalke:
    Approach ACK 8258c4c007 🌵

Tree-SHA512: 5d158add96755910837feafa8214e13695b769a6aec3a2da753cf672618bef377fac43b0f4b772a87b25dd9f0c1c9b29f2789785d7a7d47a155cdcf48f7c975d

4 files changed, 86 insertions, 5 deletions

diff --git a/src/test/fuzz/signet.cpp b/src/test/fuzz/signet.cpp
new file mode 100644
index 0000000000..4736ae27f5
--- /dev/null
+++ b/src/test/fuzz/signet.cpp
@@ -0,0 +1,34 @@
+// Copyright (c) 2020 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <chainparams.h>
+#include <consensus/validation.h>
+#include <primitives/block.h>
+#include <signet.h>
+#include <streams.h>
+#include <test/fuzz/fuzz.h>
+#include <test/fuzz/FuzzedDataProvider.h>
+#include <test/fuzz/util.h>
+
+#include <cstdint>
+#include <optional>
+#include <vector>
+
+void initialize()
+{
+    InitializeFuzzingContext(CBaseChainParams::SIGNET);
+}
+
+void test_one_input(const std::vector<uint8_t>& buffer)
+{
+    FuzzedDataProvider fuzzed_data_provider{buffer.data(), buffer.size()};
+    const std::optional<CBlock> block = ConsumeDeserializable<CBlock>(fuzzed_data_provider);
+    if (!block) {
+        return;
+    }
+    (void)CheckSignetBlockSolution(*block, Params().GetConsensus());
+    if (GetWitnessCommitmentIndex(*block) != NO_WITNESS_COMMITMENT) {
+        (void)SignetTxs(*block, ConsumeScript(fuzzed_data_provider));
+    }
+}
diff --git a/src/test/key_io_tests.cpp b/src/test/key_io_tests.cpp
index d465ee6759..611e9f2623 100644
--- a/src/test/key_io_tests.cpp
+++ b/src/test/key_io_tests.cpp
@@ -136,7 +136,7 @@ BOOST_AUTO_TEST_CASE(key_io_invalid)
         std::string exp_base58string = test[0].get_str();
 
         // must be invalid as public and as private key
-        for (const auto& chain : { CBaseChainParams::MAIN, CBaseChainParams::TESTNET, CBaseChainParams::REGTEST }) {
+        for (const auto& chain : { CBaseChainParams::MAIN, CBaseChainParams::TESTNET, CBaseChainParams::SIGNET, CBaseChainParams::REGTEST }) {
             SelectParams(chain);
             destination = DecodeDestination(exp_base58string);
             BOOST_CHECK_MESSAGE(!IsValidDestination(destination), "IsValid pubkey in mainnet:" + strTest);
diff --git a/src/test/pow_tests.cpp b/src/test/pow_tests.cpp
index 0f9872f434..ca49b89ad8 100644
--- a/src/test/pow_tests.cpp
+++ b/src/test/pow_tests.cpp
@@ -135,4 +135,51 @@ BOOST_AUTO_TEST_CASE(GetBlockProofEquivalentTime_test)
     }
 }
 
+void sanity_check_chainparams(std::string chainName)
+{
+    const auto chainParams = CreateChainParams(chainName);
+    const auto consensus = chainParams->GetConsensus();
+
+    // hash genesis is correct
+    BOOST_CHECK_EQUAL(consensus.hashGenesisBlock, chainParams->GenesisBlock().GetHash());
+
+    // target timespan is an even multiple of spacing
+    BOOST_CHECK_EQUAL(consensus.nPowTargetTimespan % consensus.nPowTargetSpacing, 0);
+
+    // genesis nBits is positive, doesn't overflow and is lower than powLimit
+    arith_uint256 pow_compact;
+    bool neg, over;
+    pow_compact.SetCompact(chainParams->GenesisBlock().nBits, &neg, &over);
+    BOOST_CHECK(!neg && pow_compact != 0);
+    BOOST_CHECK(!over);
+    BOOST_CHECK(UintToArith256(consensus.powLimit) >= pow_compact);
+
+    // check max target * 4*nPowTargetTimespan doesn't overflow -- see pow.cpp:CalculateNextWorkRequired()
+    if (!consensus.fPowNoRetargeting) {
+        arith_uint256 targ_max("0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF");
+        targ_max /= consensus.nPowTargetTimespan*4;
+        BOOST_CHECK(UintToArith256(consensus.powLimit) < targ_max);
+    }
+}
+
+BOOST_AUTO_TEST_CASE(ChainParams_MAIN_sanity)
+{
+    sanity_check_chainparams(CBaseChainParams::MAIN);
+}
+
+BOOST_AUTO_TEST_CASE(ChainParams_REGTEST_sanity)
+{
+    sanity_check_chainparams(CBaseChainParams::REGTEST);
+}
+
+BOOST_AUTO_TEST_CASE(ChainParams_TESTNET_sanity)
+{
+    sanity_check_chainparams(CBaseChainParams::TESTNET);
+}
+
+BOOST_AUTO_TEST_CASE(ChainParams_SIGNET_sanity)
+{
+    sanity_check_chainparams(CBaseChainParams::SIGNET);
+}
+
 BOOST_AUTO_TEST_SUITE_END()
diff --git a/src/test/util_tests.cpp b/src/test/util_tests.cpp
index bf7c6c3e3e..241c56934e 100644
--- a/src/test/util_tests.cpp
+++ b/src/test/util_tests.cpp
@@ -848,8 +848,8 @@ struct ArgsMergeTestingSetup : public BasicTestingSetup {
             ForEachNoDup(conf_actions, SET, SECTION_NEGATE, [&] {
                 for (bool soft_set : {false, true}) {
                     for (bool force_set : {false, true}) {
-                        for (const std::string& section : {CBaseChainParams::MAIN, CBaseChainParams::TESTNET}) {
-                            for (const std::string& network : {CBaseChainParams::MAIN, CBaseChainParams::TESTNET}) {
+                        for (const std::string& section : {CBaseChainParams::MAIN, CBaseChainParams::TESTNET, CBaseChainParams::SIGNET}) {
+                            for (const std::string& network : {CBaseChainParams::MAIN, CBaseChainParams::TESTNET, CBaseChainParams::SIGNET}) {
                                 for (bool net_specific : {false, true}) {
                                     fn(arg_actions, conf_actions, soft_set, force_set, section, network, net_specific);
                                 }
@@ -1003,7 +1003,7 @@ BOOST_FIXTURE_TEST_CASE(util_ArgsMerge, ArgsMergeTestingSetup)
     // Results file is formatted like:
     //
     //   <input> || <IsArgSet/IsArgNegated/GetArg output> | <GetArgs output> | <GetUnsuitable output>
-    BOOST_CHECK_EQUAL(out_sha_hex, "8fd4877bb8bf337badca950ede6c917441901962f160e52514e06a60dea46cde");
+    BOOST_CHECK_EQUAL(out_sha_hex, "d1e436c1cd510d0ec44d5205d4b4e3bee6387d316e0075c58206cb16603f3d82");
 }
 
 // Similar test as above, but for ArgsManager::GetChainName function.
@@ -1106,7 +1106,7 @@ BOOST_FIXTURE_TEST_CASE(util_ChainMerge, ChainMergeTestingSetup)
     // Results file is formatted like:
     //
     //   <input> || <output>
-    BOOST_CHECK_EQUAL(out_sha_hex, "f0b3a3c29869edc765d579c928f7f1690a71fbb673b49ccf39cbc4de18156a0d");
+    BOOST_CHECK_EQUAL(out_sha_hex, "f263493e300023b6509963887444c41386f44b63bc30047eb8402e8c1144854c");
 }
 
 BOOST_AUTO_TEST_CASE(util_ReadWriteSettings)