Merge #7692: Remove p2p alert system

cfd519e Add release note documentation (BtcDrak)
6601ce5 protocol.h/cpp: Removes NetMsgType::ALERT (Thomas Kerin)
ad72104 Formatting (BtcDrak)
1b77471 Remove alert keys (BtcDrak)
01fdfef Remove `-alerts` option (BtcDrak)
9206634 Update alert notification and GUI (BtcDrak)
bbb9d1d Remove p2p alert handling (BtcDrak)

17 files changed, 38 insertions, 673 deletions

diff --git a/doc/release-notes.md b/doc/release-notes.md
index 707f2357f8..43e1e3fb9a 100644
--- a/doc/release-notes.md
+++ b/doc/release-notes.md
@@ -51,6 +51,8 @@ The following outputs are affected by this change:
 
 ### P2P protocol and network code
 
+The p2p alert system has been removed in #7692 and the 'alert' message is no longer supported.
+
 ### Validation
 
 ### Build system
diff --git a/src/Makefile.am b/src/Makefile.am
index 7765ea43ed..6ad7aabae0 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -87,7 +87,6 @@ endif
 # bitcoin core #
 BITCOIN_CORE_H = \
   addrman.h \
-  alert.h \
   base58.h \
   bloom.h \
   chain.h \
@@ -176,7 +175,6 @@ libbitcoin_server_a_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES) $(MINIUPNPC_CP
 libbitcoin_server_a_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
 libbitcoin_server_a_SOURCES = \
   addrman.cpp \
-  alert.cpp \
   bloom.cpp \
   chain.cpp \
   checkpoints.cpp \
diff --git a/src/Makefile.test.include b/src/Makefile.test.include
index 820a144a95..4481349e50 100644
--- a/src/Makefile.test.include
+++ b/src/Makefile.test.include
@@ -29,7 +29,7 @@ JSON_TEST_FILES = \
   test/data/tx_valid.json \
   test/data/sighash.json
 
-RAW_TEST_FILES = test/data/alertTests.raw
+RAW_TEST_FILES =
 
 GENERATED_TEST_FILES = $(JSON_TEST_FILES:.json=.json.h) $(RAW_TEST_FILES:.raw=.raw.h)
 
diff --git a/src/alert.cpp b/src/alert.cpp
deleted file mode 100644
index eb1cd5e7f6..0000000000
--- a/src/alert.cpp
+++ /dev/null
@@ -1,266 +0,0 @@
-// Copyright (c) 2010 Satoshi Nakamoto
-// Copyright (c) 2009-2015 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 "alert.h"
-
-#include "clientversion.h"
-#include "net.h"
-#include "pubkey.h"
-#include "timedata.h"
-#include "ui_interface.h"
-#include "util.h"
-#include "utilstrencodings.h"
-
-#include <stdint.h>
-#include <algorithm>
-#include <map>
-
-#include <boost/algorithm/string/classification.hpp>
-#include <boost/algorithm/string/replace.hpp>
-#include <boost/foreach.hpp>
-#include <boost/thread.hpp>
-
-using namespace std;
-
-map<uint256, CAlert> mapAlerts;
-CCriticalSection cs_mapAlerts;
-
-void CUnsignedAlert::SetNull()
-{
-    nVersion = 1;
-    nRelayUntil = 0;
-    nExpiration = 0;
-    nID = 0;
-    nCancel = 0;
-    setCancel.clear();
-    nMinVer = 0;
-    nMaxVer = 0;
-    setSubVer.clear();
-    nPriority = 0;
-
-    strComment.clear();
-    strStatusBar.clear();
-    strReserved.clear();
-}
-
-std::string CUnsignedAlert::ToString() const
-{
-    std::string strSetCancel;
-    BOOST_FOREACH(int n, setCancel)
-        strSetCancel += strprintf("%d ", n);
-    std::string strSetSubVer;
-    BOOST_FOREACH(const std::string& str, setSubVer)
-        strSetSubVer += "\"" + str + "\" ";
-    return strprintf(
-        "CAlert(\n"
-        "    nVersion     = %d\n"
-        "    nRelayUntil  = %d\n"
-        "    nExpiration  = %d\n"
-        "    nID          = %d\n"
-        "    nCancel      = %d\n"
-        "    setCancel    = %s\n"
-        "    nMinVer      = %d\n"
-        "    nMaxVer      = %d\n"
-        "    setSubVer    = %s\n"
-        "    nPriority    = %d\n"
-        "    strComment   = \"%s\"\n"
-        "    strStatusBar = \"%s\"\n"
-        ")\n",
-        nVersion,
-        nRelayUntil,
-        nExpiration,
-        nID,
-        nCancel,
-        strSetCancel,
-        nMinVer,
-        nMaxVer,
-        strSetSubVer,
-        nPriority,
-        strComment,
-        strStatusBar);
-}
-
-void CAlert::SetNull()
-{
-    CUnsignedAlert::SetNull();
-    vchMsg.clear();
-    vchSig.clear();
-}
-
-bool CAlert::IsNull() const
-{
-    return (nExpiration == 0);
-}
-
-uint256 CAlert::GetHash() const
-{
-    return Hash(this->vchMsg.begin(), this->vchMsg.end());
-}
-
-bool CAlert::IsInEffect() const
-{
-    return (GetAdjustedTime() < nExpiration);
-}
-
-bool CAlert::Cancels(const CAlert& alert) const
-{
-    if (!IsInEffect())
-        return false; // this was a no-op before 31403
-    return (alert.nID <= nCancel || setCancel.count(alert.nID));
-}
-
-bool CAlert::AppliesTo(int nVersion, const std::string& strSubVerIn) const
-{
-    // TODO: rework for client-version-embedded-in-strSubVer ?
-    return (IsInEffect() &&
-            nMinVer <= nVersion && nVersion <= nMaxVer &&
-            (setSubVer.empty() || setSubVer.count(strSubVerIn)));
-}
-
-bool CAlert::AppliesToMe() const
-{
-    return AppliesTo(PROTOCOL_VERSION, FormatSubVersion(CLIENT_NAME, CLIENT_VERSION, std::vector<std::string>()));
-}
-
-bool CAlert::RelayTo(CNode* pnode) const
-{
-    if (!IsInEffect())
-        return false;
-    // don't relay to nodes which haven't sent their version message
-    if (pnode->nVersion == 0)
-        return false;
-    // returns true if wasn't already contained in the set
-    if (pnode->setKnown.insert(GetHash()).second)
-    {
-        if (AppliesTo(pnode->nVersion, pnode->strSubVer) ||
-            AppliesToMe() ||
-            GetAdjustedTime() < nRelayUntil)
-        {
-            pnode->PushMessage(NetMsgType::ALERT, *this);
-            return true;
-        }
-    }
-    return false;
-}
-
-bool CAlert::CheckSignature(const std::vector<unsigned char>& alertKey) const
-{
-    CPubKey key(alertKey);
-    if (!key.Verify(Hash(vchMsg.begin(), vchMsg.end()), vchSig))
-        return error("CAlert::CheckSignature(): verify signature failed");
-
-    // Now unserialize the data
-    CDataStream sMsg(vchMsg, SER_NETWORK, PROTOCOL_VERSION);
-    sMsg >> *(CUnsignedAlert*)this;
-    return true;
-}
-
-CAlert CAlert::getAlertByHash(const uint256 &hash)
-{
-    CAlert retval;
-    {
-        LOCK(cs_mapAlerts);
-        map<uint256, CAlert>::iterator mi = mapAlerts.find(hash);
-        if(mi != mapAlerts.end())
-            retval = mi->second;
-    }
-    return retval;
-}
-
-bool CAlert::ProcessAlert(const std::vector<unsigned char>& alertKey, bool fThread)
-{
-    if (!CheckSignature(alertKey))
-        return false;
-    if (!IsInEffect())
-        return false;
-
-    // alert.nID=max is reserved for if the alert key is
-    // compromised. It must have a pre-defined message,
-    // must never expire, must apply to all versions,
-    // and must cancel all previous
-    // alerts or it will be ignored (so an attacker can't
-    // send an "everything is OK, don't panic" version that
-    // cannot be overridden):
-    int maxInt = std::numeric_limits<int>::max();
-    if (nID == maxInt)
-    {
-        if (!(
-                nExpiration == maxInt &&
-                nCancel == (maxInt-1) &&
-                nMinVer == 0 &&
-                nMaxVer == maxInt &&
-                setSubVer.empty() &&
-                nPriority == maxInt &&
-                strStatusBar == "URGENT: Alert key compromised, upgrade required"
-                ))
-            return false;
-    }
-
-    {
-        LOCK(cs_mapAlerts);
-        // Cancel previous alerts
-        for (map<uint256, CAlert>::iterator mi = mapAlerts.begin(); mi != mapAlerts.end();)
-        {
-            const CAlert& alert = (*mi).second;
-            if (Cancels(alert))
-            {
-                LogPrint("alert", "cancelling alert %d\n", alert.nID);
-                uiInterface.NotifyAlertChanged((*mi).first, CT_DELETED);
-                mapAlerts.erase(mi++);
-            }
-            else if (!alert.IsInEffect())
-            {
-                LogPrint("alert", "expiring alert %d\n", alert.nID);
-                uiInterface.NotifyAlertChanged((*mi).first, CT_DELETED);
-                mapAlerts.erase(mi++);
-            }
-            else
-                mi++;
-        }
-
-        // Check if this alert has been cancelled
-        BOOST_FOREACH(PAIRTYPE(const uint256, CAlert)& item, mapAlerts)
-        {
-            const CAlert& alert = item.second;
-            if (alert.Cancels(*this))
-            {
-                LogPrint("alert", "alert already cancelled by %d\n", alert.nID);
-                return false;
-            }
-        }
-
-        // Add to mapAlerts
-        mapAlerts.insert(make_pair(GetHash(), *this));
-        // Notify UI and -alertnotify if it applies to me
-        if(AppliesToMe())
-        {
-            uiInterface.NotifyAlertChanged(GetHash(), CT_NEW);
-            Notify(strStatusBar, fThread);
-        }
-    }
-
-    LogPrint("alert", "accepted alert %d, AppliesToMe()=%d\n", nID, AppliesToMe());
-    return true;
-}
-
-void
-CAlert::Notify(const std::string& strMessage, bool fThread)
-{
-    std::string strCmd = GetArg("-alertnotify", "");
-    if (strCmd.empty()) return;
-
-    // Alert text should be plain ascii coming from a trusted source, but to
-    // be safe we first strip anything not in safeChars, then add single quotes around
-    // the whole string before passing it to the shell:
-    std::string singleQuote("'");
-    std::string safeStatus = SanitizeString(strMessage);
-    safeStatus = singleQuote+safeStatus+singleQuote;
-    boost::replace_all(strCmd, "%s", safeStatus);
-
-    if (fThread)
-        boost::thread t(runCommand, strCmd); // thread runs free
-    else
-        runCommand(strCmd);
-}
diff --git a/src/alert.h b/src/alert.h
deleted file mode 100644
index 8cb86e338c..0000000000
--- a/src/alert.h
+++ /dev/null
@@ -1,113 +0,0 @@
-// Copyright (c) 2010 Satoshi Nakamoto
-// Copyright (c) 2009-2015 The Bitcoin Core developers
-// Distributed under the MIT software license, see the accompanying
-// file COPYING or http://www.opensource.org/licenses/mit-license.php.
-
-#ifndef BITCOIN_ALERT_H
-#define BITCOIN_ALERT_H
-
-#include "serialize.h"
-#include "sync.h"
-
-#include <map>
-#include <set>
-#include <stdint.h>
-#include <string>
-
-class CAlert;
-class CNode;
-class uint256;
-
-extern std::map<uint256, CAlert> mapAlerts;
-extern CCriticalSection cs_mapAlerts;
-
-/** Alerts are for notifying old versions if they become too obsolete and
- * need to upgrade.  The message is displayed in the status bar.
- * Alert messages are broadcast as a vector of signed data.  Unserializing may
- * not read the entire buffer if the alert is for a newer version, but older
- * versions can still relay the original data.
- */
-class CUnsignedAlert
-{
-public:
-    int nVersion;
-    int64_t nRelayUntil;      // when newer nodes stop relaying to newer nodes
-    int64_t nExpiration;
-    int nID;
-    int nCancel;
-    std::set<int> setCancel;
-    int nMinVer;            // lowest version inclusive
-    int nMaxVer;            // highest version inclusive
-    std::set<std::string> setSubVer;  // empty matches all
-    int nPriority;
-
-    // Actions
-    std::string strComment;
-    std::string strStatusBar;
-    std::string strReserved;
-
-    ADD_SERIALIZE_METHODS;
-
-    template <typename Stream, typename Operation>
-    inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) {
-        READWRITE(this->nVersion);
-        nVersion = this->nVersion;
-        READWRITE(nRelayUntil);
-        READWRITE(nExpiration);
-        READWRITE(nID);
-        READWRITE(nCancel);
-        READWRITE(setCancel);
-        READWRITE(nMinVer);
-        READWRITE(nMaxVer);
-        READWRITE(setSubVer);
-        READWRITE(nPriority);
-
-        READWRITE(LIMITED_STRING(strComment, 65536));
-        READWRITE(LIMITED_STRING(strStatusBar, 256));
-        READWRITE(LIMITED_STRING(strReserved, 256));
-    }
-
-    void SetNull();
-
-    std::string ToString() const;
-};
-
-/** An alert is a combination of a serialized CUnsignedAlert and a signature. */
-class CAlert : public CUnsignedAlert
-{
-public:
-    std::vector<unsigned char> vchMsg;
-    std::vector<unsigned char> vchSig;
-
-    CAlert()
-    {
-        SetNull();
-    }
-
-    ADD_SERIALIZE_METHODS;
-
-    template <typename Stream, typename Operation>
-    inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) {
-        READWRITE(vchMsg);
-        READWRITE(vchSig);
-    }
-
-    void SetNull();
-    bool IsNull() const;
-    uint256 GetHash() const;
-    bool IsInEffect() const;
-    bool Cancels(const CAlert& alert) const;
-    bool AppliesTo(int nVersion, const std::string& strSubVerIn) const;
-    bool AppliesToMe() const;
-    bool RelayTo(CNode* pnode) const;
-    bool CheckSignature(const std::vector<unsigned char>& alertKey) const;
-    bool ProcessAlert(const std::vector<unsigned char>& alertKey, bool fThread = true); // fThread means run -alertnotify in a free-running thread
-    static void Notify(const std::string& strMessage, bool fThread);
-
-    /*
-     * Get copy of (active) alert object by hash. Returns a null alert if it is not found.
-     */
-    static CAlert getAlertByHash(const uint256 &hash);
-};
-
-#endif // BITCOIN_ALERT_H
diff --git a/src/chainparams.cpp b/src/chainparams.cpp
index 35e090a0b3..508c4de167 100644
--- a/src/chainparams.cpp
+++ b/src/chainparams.cpp
@@ -95,7 +95,6 @@ public:
         pchMessageStart[1] = 0xbe;
         pchMessageStart[2] = 0xb4;
         pchMessageStart[3] = 0xd9;
-        vAlertPubKey = ParseHex("04fc9702847840aaf195de8442ebecedf5b095cdbb9bc716bda9110971b28a49e0ead8564ff0db22209e0374782c093bb899692d524e9d6a6956e7c5ecbcd68284");
         nDefaultPort = 8333;
         nPruneAfterHeight = 100000;
 
@@ -176,7 +175,6 @@ public:
         pchMessageStart[1] = 0x11;
         pchMessageStart[2] = 0x09;
         pchMessageStart[3] = 0x07;
-        vAlertPubKey = ParseHex("04302390343f91cc401d56d68b123028bf52e5fca1939df127f63c6467cdf9c8e2c14b61104cf817d0b780da337893ecc4aaff1309e536162dabbdb45200ca2b0a");
         nDefaultPort = 18333;
         nPruneAfterHeight = 1000;
 
diff --git a/src/chainparams.h b/src/chainparams.h
index 88bc666765..59202f548a 100644
--- a/src/chainparams.h
+++ b/src/chainparams.h
@@ -54,7 +54,6 @@ public:
 
     const Consensus::Params& GetConsensus() const { return consensus; }
     const CMessageHeader::MessageStartChars& MessageStart() const { return pchMessageStart; }
-    const std::vector<unsigned char>& AlertKey() const { return vAlertPubKey; }
     int GetDefaultPort() const { return nDefaultPort; }
 
     const CBlock& GenesisBlock() const { return genesis; }
@@ -80,8 +79,6 @@ protected:
 
     Consensus::Params consensus;
     CMessageHeader::MessageStartChars pchMessageStart;
-    //! Raw pub key bytes for the broadcast alert signing key.
-    std::vector<unsigned char> vAlertPubKey;
     int nDefaultPort;
     uint64_t nPruneAfterHeight;
     std::vector<CDNSSeedData> vSeeds;
diff --git a/src/init.cpp b/src/init.cpp
index fa97521a23..f53d7d3c3c 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -315,7 +315,6 @@ std::string HelpMessage(HelpMessageMode mode)
     string strUsage = HelpMessageGroup(_("Options:"));
     strUsage += HelpMessageOpt("-?", _("Print this help message and exit"));
     strUsage += HelpMessageOpt("-version", _("Print version and exit"));
-    strUsage += HelpMessageOpt("-alerts", strprintf(_("Receive and display P2P network alerts (default: %u)"), DEFAULT_ALERTS));
     strUsage += HelpMessageOpt("-alertnotify=<cmd>", _("Execute command when a relevant alert is received or we see a really long fork (%s in cmd is replaced by message)"));
     strUsage += HelpMessageOpt("-blocknotify=<cmd>", _("Execute command when the best block changes (%s in cmd is replaced by block hash)"));
     if (showDebug)
@@ -1000,8 +999,6 @@ bool AppInit2(boost::thread_group& threadGroup, CScheduler& scheduler)
     fAcceptDatacarrier = GetBoolArg("-datacarrier", DEFAULT_ACCEPT_DATACARRIER);
     nMaxDatacarrierBytes = GetArg("-datacarriersize", nMaxDatacarrierBytes);
 
-    fAlerts = GetBoolArg("-alerts", DEFAULT_ALERTS);
-
     // Option to startup with mocktime set (used for regression testing):
     SetMockTime(GetArg("-mocktime", 0)); // SetMockTime(0) is a no-op
 
diff --git a/src/main.cpp b/src/main.cpp
index 16b26444dc..fc443cfb72 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -6,7 +6,6 @@
 #include "main.h"
 
 #include "addrman.h"
-#include "alert.h"
 #include "arith_uint256.h"
 #include "chainparams.h"
 #include "checkpoints.h"
@@ -75,7 +74,6 @@ bool fCheckBlockIndex = false;
 bool fCheckpointsEnabled = DEFAULT_CHECKPOINTS_ENABLED;
 size_t nCoinCacheUsage = 5000 * 300;
 uint64_t nPruneTarget = 0;
-bool fAlerts = DEFAULT_ALERTS;
 int64_t nMaxTipAge = DEFAULT_MAX_TIP_AGE;
 bool fEnableReplacement = DEFAULT_ENABLE_REPLACEMENT;
 
@@ -1566,6 +1564,26 @@ bool fLargeWorkForkFound = false;
 bool fLargeWorkInvalidChainFound = false;
 CBlockIndex *pindexBestForkTip = NULL, *pindexBestForkBase = NULL;
 
+static void AlertNotify(const std::string& strMessage, bool fThread)
+{
+    uiInterface.NotifyAlertChanged();
+    std::string strCmd = GetArg("-alertnotify", "");
+    if (strCmd.empty()) return;
+
+    // Alert text should be plain ascii coming from a trusted source, but to
+    // be safe we first strip anything not in safeChars, then add single quotes around
+    // the whole string before passing it to the shell:
+    std::string singleQuote("'");
+    std::string safeStatus = SanitizeString(strMessage);
+    safeStatus = singleQuote+safeStatus+singleQuote;
+    boost::replace_all(strCmd, "%s", safeStatus);
+
+    if (fThread)
+        boost::thread t(runCommand, strCmd); // thread runs free
+    else
+        runCommand(strCmd);
+}
+
 void CheckForkWarningConditions()
 {
     AssertLockHeld(cs_main);
@@ -1585,7 +1603,7 @@ void CheckForkWarningConditions()
         {
             std::string warning = std::string("'Warning: Large-work fork detected, forking after block ") +
                 pindexBestForkBase->phashBlock->ToString() + std::string("'");
-            CAlert::Notify(warning, true);
+            AlertNotify(warning, true);
         }
         if (pindexBestForkTip && pindexBestForkBase)
         {
@@ -2116,7 +2134,7 @@ void PartitionCheck(bool (*initialDownloadCheck)(), CCriticalSection& cs, const
     if (!strWarning.empty())
     {
         strMiscWarning = strWarning;
-        CAlert::Notify(strWarning, true);
+        AlertNotify(strWarning, true);
         lastAlertTime = now;
     }
 }
@@ -2546,7 +2564,7 @@ void static UpdateTip(CBlockIndex *pindexNew) {
                 if (state == THRESHOLD_ACTIVE) {
                     strMiscWarning = strprintf(_("Warning: unknown new rules activated (versionbit %i)"), bit);
                     if (!fWarned) {
-                        CAlert::Notify(strMiscWarning, true);
+                        AlertNotify(strMiscWarning, true);
                         fWarned = true;
                     }
                 } else {
@@ -2568,7 +2586,7 @@ void static UpdateTip(CBlockIndex *pindexNew) {
             // strMiscWarning is read by GetWarnings(), called by Qt and the JSON-RPC code to warn the user:
             strMiscWarning = _("Warning: Unknown block versions being mined! It's possible unknown rules are in effect");
             if (!fWarned) {
-                CAlert::Notify(strMiscWarning, true);
+                AlertNotify(strMiscWarning, true);
                 fWarned = true;
             }
         }
@@ -4213,14 +4231,8 @@ void static CheckBlockIndex(const Consensus::Params& consensusParams)
     assert(nNodes == forward.size());
 }
 
-//////////////////////////////////////////////////////////////////////////////
-//
-// CAlert
-//
-
 std::string GetWarnings(const std::string& strFor)
 {
-    int nPriority = 0;
     string strStatusBar;
     string strRPC;
     string strGUI;
@@ -4236,37 +4248,20 @@ std::string GetWarnings(const std::string& strFor)
     // Misc warnings like out of disk space and clock is wrong
     if (strMiscWarning != "")
     {
-        nPriority = 1000;
         strStatusBar = strGUI = strMiscWarning;
     }
 
     if (fLargeWorkForkFound)
     {
-        nPriority = 2000;
         strStatusBar = strRPC = "Warning: The network does not appear to fully agree! Some miners appear to be experiencing issues.";
         strGUI = _("Warning: The network does not appear to fully agree! Some miners appear to be experiencing issues.");
     }
     else if (fLargeWorkInvalidChainFound)
     {
-        nPriority = 2000;
         strStatusBar = strRPC = "Warning: We do not appear to fully agree with our peers! You may need to upgrade, or other nodes may need to upgrade.";
         strGUI = _("Warning: We do not appear to fully agree with our peers! You may need to upgrade, or other nodes may need to upgrade.");
     }
 
-    // Alerts
-    {
-        LOCK(cs_mapAlerts);
-        BOOST_FOREACH(PAIRTYPE(const uint256, CAlert)& item, mapAlerts)
-        {
-            const CAlert& alert = item.second;
-            if (alert.AppliesToMe() && alert.nPriority > nPriority)
-            {
-                nPriority = alert.nPriority;
-                strStatusBar = strGUI = alert.strStatusBar;
-            }
-        }
-    }
-
     if (strFor == "gui")
         return strGUI;
     else if (strFor == "statusbar")
@@ -4588,13 +4583,6 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
             }
         }
 
-        // Relay alerts
-        {
-            LOCK(cs_mapAlerts);
-            BOOST_FOREACH(PAIRTYPE(const uint256, CAlert)& item, mapAlerts)
-                item.second.RelayTo(pfrom);
-        }
-
         pfrom->fSuccessfullyConnected = true;
 
         string remoteAddr;
@@ -5302,37 +5290,6 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
     }
 
 
-    else if (fAlerts && strCommand == NetMsgType::ALERT)
-    {
-        CAlert alert;
-        vRecv >> alert;
-
-        uint256 alertHash = alert.GetHash();
-        if (pfrom->setKnown.count(alertHash) == 0)
-        {
-            if (alert.ProcessAlert(chainparams.AlertKey()))
-            {
-                // Relay
-                pfrom->setKnown.insert(alertHash);
-                {
-                    LOCK(cs_vNodes);
-                    BOOST_FOREACH(CNode* pnode, vNodes)
-                        alert.RelayTo(pnode);
-                }
-            }
-            else {
-                // Small DoS penalty so peers that send us lots of
-                // duplicate/expired/invalid-signature/whatever alerts
-                // eventually get banned.
-                // This isn't a Misbehaving(100) (immediate ban) because the
-                // peer might be an older or different implementation with
-                // a different signature key, etc.
-                Misbehaving(pfrom->GetId(), 10);
-            }
-        }
-    }
-
-
     else if (strCommand == NetMsgType::FILTERLOAD)
     {
         CBloomFilter filter;
diff --git a/src/main.h b/src/main.h
index ecb1efa5cb..a011ba4e55 100644
--- a/src/main.h
+++ b/src/main.h
@@ -42,8 +42,6 @@ class CValidationState;
 struct CNodeStateStats;
 struct LockPoints;
 
-/** Default for accepting alerts from the P2P network. */
-static const bool DEFAULT_ALERTS = true;
 /** Default for DEFAULT_WHITELISTRELAY. */
 static const bool DEFAULT_WHITELISTRELAY = true;
 /** Default for DEFAULT_WHITELISTFORCERELAY. */
@@ -154,7 +152,6 @@ extern size_t nCoinCacheUsage;
 extern CFeeRate minRelayTxFee;
 /** Absolute maximum transaction fee (in satoshis) used by wallet and mempool (rejects high fee in sendrawtransaction) */
 extern CAmount maxTxFee;
-extern bool fAlerts;
 /** If the tip is older than this (in seconds), the node is considered to be in initial block download. */
 extern int64_t nMaxTipAge;
 extern bool fEnableReplacement;
diff --git a/src/protocol.cpp b/src/protocol.cpp
index c1c7c0b96b..1ddb65b796 100644
--- a/src/protocol.cpp
+++ b/src/protocol.cpp
@@ -28,7 +28,6 @@ const char *GETADDR="getaddr";
 const char *MEMPOOL="mempool";
 const char *PING="ping";
 const char *PONG="pong";
-const char *ALERT="alert";
 const char *NOTFOUND="notfound";
 const char *FILTERLOAD="filterload";
 const char *FILTERADD="filteradd";
@@ -64,7 +63,6 @@ const static std::string allNetMessageTypes[] = {
     NetMsgType::MEMPOOL,
     NetMsgType::PING,
     NetMsgType::PONG,
-    NetMsgType::ALERT,
     NetMsgType::NOTFOUND,
     NetMsgType::FILTERLOAD,
     NetMsgType::FILTERADD,
diff --git a/src/protocol.h b/src/protocol.h
index c8b8d20ead..5504f213f4 100644
--- a/src/protocol.h
+++ b/src/protocol.h
@@ -164,13 +164,6 @@ extern const char *PING;
  */
 extern const char *PONG;
 /**
- * The alert message warns nodes of problems that may affect them or the rest
- * of the network.
- * @since protocol version 311.
- * @see https://bitcoin.org/en/developer-reference#alert
- */
-extern const char *ALERT;
-/**
  * The notfound message is a reply to a getdata message which requested an
  * object the receiving node does not have available for relay.
  * @ince protocol version 70001.
diff --git a/src/qt/clientmodel.cpp b/src/qt/clientmodel.cpp
index fb502b3c81..d3edfedff2 100644
--- a/src/qt/clientmodel.cpp
+++ b/src/qt/clientmodel.cpp
@@ -8,7 +8,6 @@
 #include "guiconstants.h"
 #include "peertablemodel.h"
 
-#include "alert.h"
 #include "chainparams.h"
 #include "checkpoints.h"
 #include "clientversion.h"
@@ -122,20 +121,8 @@ void ClientModel::updateNumConnections(int numConnections)
     Q_EMIT numConnectionsChanged(numConnections);
 }
 
-void ClientModel::updateAlert(const QString &hash, int status)
+void ClientModel::updateAlert()
 {
-    // Show error message notification for new alert
-    if(status == CT_NEW)
-    {
-        uint256 hash_256;
-        hash_256.SetHex(hash.toStdString());
-        CAlert alert = CAlert::getAlertByHash(hash_256);
-        if(!alert.IsNull())
-        {
-            Q_EMIT message(tr("Network Alert"), QString::fromStdString(alert.strStatusBar), CClientUIInterface::ICON_ERROR);
-        }
-    }
-
     Q_EMIT alertsChanged(getStatusBarWarnings());
 }
 
@@ -227,12 +214,10 @@ static void NotifyNumConnectionsChanged(ClientModel *clientmodel, int newNumConn
                               Q_ARG(int, newNumConnections));
 }
 
-static void NotifyAlertChanged(ClientModel *clientmodel, const uint256 &hash, ChangeType status)
+static void NotifyAlertChanged(ClientModel *clientmodel)
 {
-    qDebug() << "NotifyAlertChanged: " + QString::fromStdString(hash.GetHex()) + " status=" + QString::number(status);
-    QMetaObject::invokeMethod(clientmodel, "updateAlert", Qt::QueuedConnection,
-                              Q_ARG(QString, QString::fromStdString(hash.GetHex())),
-                              Q_ARG(int, status));
+    qDebug() << "NotifyAlertChanged";
+    QMetaObject::invokeMethod(clientmodel, "updateAlert", Qt::QueuedConnection);
 }
 
 static void BannedListChanged(ClientModel *clientmodel)
@@ -266,7 +251,7 @@ void ClientModel::subscribeToCoreSignals()
     // Connect signals to client
     uiInterface.ShowProgress.connect(boost::bind(ShowProgress, this, _1, _2));
     uiInterface.NotifyNumConnectionsChanged.connect(boost::bind(NotifyNumConnectionsChanged, this, _1));
-    uiInterface.NotifyAlertChanged.connect(boost::bind(NotifyAlertChanged, this, _1, _2));
+    uiInterface.NotifyAlertChanged.connect(boost::bind(NotifyAlertChanged, this));
     uiInterface.BannedListChanged.connect(boost::bind(BannedListChanged, this));
     uiInterface.NotifyBlockTip.connect(boost::bind(BlockTipChanged, this, _1, _2));
 }
@@ -276,7 +261,7 @@ void ClientModel::unsubscribeFromCoreSignals()
     // Disconnect signals from client
     uiInterface.ShowProgress.disconnect(boost::bind(ShowProgress, this, _1, _2));
     uiInterface.NotifyNumConnectionsChanged.disconnect(boost::bind(NotifyNumConnectionsChanged, this, _1));
-    uiInterface.NotifyAlertChanged.disconnect(boost::bind(NotifyAlertChanged, this, _1, _2));
+    uiInterface.NotifyAlertChanged.disconnect(boost::bind(NotifyAlertChanged, this));
     uiInterface.BannedListChanged.disconnect(boost::bind(BannedListChanged, this));
     uiInterface.NotifyBlockTip.disconnect(boost::bind(BlockTipChanged, this, _1, _2));
 }
diff --git a/src/qt/clientmodel.h b/src/qt/clientmodel.h
index 62c9f71ac7..2fef6131c3 100644
--- a/src/qt/clientmodel.h
+++ b/src/qt/clientmodel.h
@@ -103,7 +103,7 @@ Q_SIGNALS:
 public Q_SLOTS:
     void updateTimer();
     void updateNumConnections(int numConnections);
-    void updateAlert(const QString &hash, int status);
+    void updateAlert();
     void updateBanlist();
 };
 
diff --git a/src/test/alert_tests.cpp b/src/test/alert_tests.cpp
index 87d35be412..70f1f12273 100644
--- a/src/test/alert_tests.cpp
+++ b/src/test/alert_tests.cpp
@@ -4,193 +4,16 @@
 
 // Unit tests for alert system
 
-#include "alert.h"
-#include "chain.h"
 #include "chainparams.h"
-#include "clientversion.h"
-#include "data/alertTests.raw.h"
 #include "main.h" // For PartitionCheck
-#include "serialize.h"
-#include "streams.h"
-#include "utilstrencodings.h"
 
 #include "test/testutil.h"
 #include "test/test_bitcoin.h"
 
-#include <fstream>
-
-#include <boost/filesystem/operations.hpp>
-#include <boost/foreach.hpp>
 #include <boost/test/unit_test.hpp>
 
-#if 0
-//
-// alertTests contains 7 alerts, generated with this code:
-// (SignAndSave code not shown, alert signing key is secret)
-//
-{
-    CAlert alert;
-    alert.nRelayUntil   = 60;
-    alert.nExpiration   = 24 * 60 * 60;
-    alert.nID           = 1;
-    alert.nCancel       = 0;   // cancels previous messages up to this ID number
-    alert.nMinVer       = 0;  // These versions are protocol versions
-    alert.nMaxVer       = 999001;
-    alert.nPriority     = 1;
-    alert.strComment    = "Alert comment";
-    alert.strStatusBar  = "Alert 1";
-
-    SignAndSave(alert, "test/alertTests");
-
-    alert.setSubVer.insert(std::string("/Satoshi:0.1.0/"));
-    alert.strStatusBar  = "Alert 1 for Satoshi 0.1.0";
-    SignAndSave(alert, "test/alertTests");
-
-    alert.setSubVer.insert(std::string("/Satoshi:0.2.0/"));
-    alert.strStatusBar  = "Alert 1 for Satoshi 0.1.0, 0.2.0";
-    SignAndSave(alert, "test/alertTests");
-
-    alert.setSubVer.clear();
-    ++alert.nID;
-    alert.nCancel = 1;
-    alert.nPriority = 100;
-    alert.strStatusBar  = "Alert 2, cancels 1";
-    SignAndSave(alert, "test/alertTests");
-
-    alert.nExpiration += 60;
-    ++alert.nID;
-    SignAndSave(alert, "test/alertTests");
-
-    ++alert.nID;
-    alert.nMinVer = 11;
-    alert.nMaxVer = 22;
-    SignAndSave(alert, "test/alertTests");
-
-    ++alert.nID;
-    alert.strStatusBar  = "Alert 2 for Satoshi 0.1.0";
-    alert.setSubVer.insert(std::string("/Satoshi:0.1.0/"));
-    SignAndSave(alert, "test/alertTests");
-
-    ++alert.nID;
-    alert.nMinVer = 0;
-    alert.nMaxVer = 999999;
-    alert.strStatusBar  = "Evil Alert'; /bin/ls; echo '";
-    alert.setSubVer.clear();
-    SignAndSave(alert, "test/alertTests");
-}
-#endif
-
-struct ReadAlerts : public TestingSetup
-{
-    ReadAlerts()
-    {
-        std::vector<unsigned char> vch(alert_tests::alertTests, alert_tests::alertTests + sizeof(alert_tests::alertTests));
-        CDataStream stream(vch, SER_DISK, CLIENT_VERSION);
-        try {
-            while (!stream.eof())
-            {
-                CAlert alert;
-                stream >> alert;
-                alerts.push_back(alert);
-            }
-        }
-        catch (const std::exception&) { }
-    }
-    ~ReadAlerts() { }
-
-    static std::vector<std::string> read_lines(boost::filesystem::path filepath)
-    {
-        std::vector<std::string> result;
-
-        std::ifstream f(filepath.string().c_str());
-        std::string line;
-        while (std::getline(f,line))
-            result.push_back(line);
-
-        return result;
-    }
-
-    std::vector<CAlert> alerts;
-};
-
-BOOST_FIXTURE_TEST_SUITE(Alert_tests, ReadAlerts)
-
-
-BOOST_AUTO_TEST_CASE(AlertApplies)
-{
-    SetMockTime(11);
-    const std::vector<unsigned char>& alertKey = Params(CBaseChainParams::MAIN).AlertKey();
+BOOST_FIXTURE_TEST_SUITE(Alert_tests, TestingSetup)
 
-    BOOST_FOREACH(const CAlert& alert, alerts)
-    {
-        BOOST_CHECK(alert.CheckSignature(alertKey));
-    }
-
-    BOOST_CHECK(alerts.size() >= 3);
-
-    // Matches:
-    BOOST_CHECK(alerts[0].AppliesTo(1, ""));
-    BOOST_CHECK(alerts[0].AppliesTo(999001, ""));
-    BOOST_CHECK(alerts[0].AppliesTo(1, "/Satoshi:11.11.11/"));
-
-    BOOST_CHECK(alerts[1].AppliesTo(1, "/Satoshi:0.1.0/"));
-    BOOST_CHECK(alerts[1].AppliesTo(999001, "/Satoshi:0.1.0/"));
-
-    BOOST_CHECK(alerts[2].AppliesTo(1, "/Satoshi:0.1.0/"));
-    BOOST_CHECK(alerts[2].AppliesTo(1, "/Satoshi:0.2.0/"));
-
-    // Don't match:
-    BOOST_CHECK(!alerts[0].AppliesTo(-1, ""));
-    BOOST_CHECK(!alerts[0].AppliesTo(999002, ""));
-
-    BOOST_CHECK(!alerts[1].AppliesTo(1, ""));
-    BOOST_CHECK(!alerts[1].AppliesTo(1, "Satoshi:0.1.0"));
-    BOOST_CHECK(!alerts[1].AppliesTo(1, "/Satoshi:0.1.0"));
-    BOOST_CHECK(!alerts[1].AppliesTo(1, "Satoshi:0.1.0/"));
-    BOOST_CHECK(!alerts[1].AppliesTo(-1, "/Satoshi:0.1.0/"));
-    BOOST_CHECK(!alerts[1].AppliesTo(999002, "/Satoshi:0.1.0/"));
-    BOOST_CHECK(!alerts[1].AppliesTo(1, "/Satoshi:0.2.0/"));
-
-    BOOST_CHECK(!alerts[2].AppliesTo(1, "/Satoshi:0.3.0/"));
-
-    SetMockTime(0);
-}
-
-
-BOOST_AUTO_TEST_CASE(AlertNotify)
-{
-    SetMockTime(11);
-    const std::vector<unsigned char>& alertKey = Params(CBaseChainParams::MAIN).AlertKey();
-
-    boost::filesystem::path temp = GetTempPath() /
-        boost::filesystem::unique_path("alertnotify-%%%%.txt");
-
-    mapArgs["-alertnotify"] = std::string("echo %s >> ") + temp.string();
-
-    BOOST_FOREACH(CAlert alert, alerts)
-        alert.ProcessAlert(alertKey, false);
-
-    std::vector<std::string> r = read_lines(temp);
-    BOOST_CHECK_EQUAL(r.size(), 4u);
-
-// Windows built-in echo semantics are different than posixy shells. Quotes and
-// whitespace are printed literally.
-
-#ifndef WIN32
-    BOOST_CHECK_EQUAL(r[0], "Alert 1");
-    BOOST_CHECK_EQUAL(r[1], "Alert 2, cancels 1");
-    BOOST_CHECK_EQUAL(r[2], "Alert 2, cancels 1");
-    BOOST_CHECK_EQUAL(r[3], "Evil Alert; /bin/ls; echo "); // single-quotes should be removed
-#else
-    BOOST_CHECK_EQUAL(r[0], "'Alert 1' ");
-    BOOST_CHECK_EQUAL(r[1], "'Alert 2, cancels 1' ");
-    BOOST_CHECK_EQUAL(r[2], "'Alert 2, cancels 1' ");
-    BOOST_CHECK_EQUAL(r[3], "'Evil Alert; /bin/ls; echo ' ");
-#endif
-    boost::filesystem::remove(temp);
-
-    SetMockTime(0);
-}
 
 static bool falseFunc() { return false; }
 
@@ -253,4 +76,4 @@ BOOST_AUTO_TEST_CASE(PartitionAlert)
     SetMockTime(0);
 }
 
-BOOST_AUTO_TEST_SUITE_END()
+BOOST_AUTO_TEST_SUITE_END()
\ No newline at end of file
diff --git a/src/test/data/alertTests.raw b/src/test/data/alertTests.raw
deleted file mode 100644
index 01f50680b9..0000000000
--- a/src/test/data/alertTests.raw
+++ /dev/null
diff --git a/src/ui_interface.h b/src/ui_interface.h
index 967d243270..0b51d52e65 100644
--- a/src/ui_interface.h
+++ b/src/ui_interface.h
@@ -83,10 +83,9 @@ public:
     boost::signals2::signal<void (int newNumConnections)> NotifyNumConnectionsChanged;
 
     /**
-     * New, updated or cancelled alert.
-     * @note called with lock cs_mapAlerts held.
+     * Status bar alerts changed.
      */
-    boost::signals2::signal<void (const uint256 &hash, ChangeType status)> NotifyAlertChanged;
+    boost::signals2::signal<void ()> NotifyAlertChanged;
 
     /** A wallet has been loaded. */
     boost::signals2::signal<void (CWallet* wallet)> LoadWallet;