diff --git a/dbms/CMakeLists.txt b/dbms/CMakeLists.txt
index 849784e41bd..38127891e4d 100644
--- a/dbms/CMakeLists.txt
+++ b/dbms/CMakeLists.txt
@@ -412,6 +412,6 @@ if (ENABLE_TESTS AND USE_GTEST)
     # gtest framework has substandard code
     target_compile_options(unit_tests_dbms PRIVATE -Wno-zero-as-null-pointer-constant -Wno-undef -Wno-sign-compare -Wno-used-but-marked-unused -Wno-missing-noreturn)
 
-    target_link_libraries(unit_tests_dbms PRIVATE ${GTEST_BOTH_LIBRARIES} clickhouse_functions clickhouse_parsers dbms clickhouse_common_zookeeper)
+    target_link_libraries(unit_tests_dbms PRIVATE ${GTEST_BOTH_LIBRARIES} clickhouse_functions clickhouse_parsers dbms clickhouse_common_zookeeper string_utils)
     add_check(unit_tests_dbms)
 endif ()
diff --git a/dbms/programs/client/Client.cpp b/dbms/programs/client/Client.cpp
index 091a1ac063f..88e485a66ab 100644
--- a/dbms/programs/client/Client.cpp
+++ b/dbms/programs/client/Client.cpp
@@ -607,6 +607,7 @@ private:
 
             if (!ends_with_backslash && (ends_with_semicolon || has_vertical_output_suffix || (!config().has("multiline") && !hasDataInSTDIN())))
             {
+                // TODO: should we do sensitive data masking on client too? History file can be source of secret leaks.
                 if (input != prev_input)
                 {
                     /// Replace line breaks with spaces to prevent the following problem.
diff --git a/dbms/programs/local/LocalServer.cpp b/dbms/programs/local/LocalServer.cpp
index bed55a0fc5f..6b07fc93ee0 100644
--- a/dbms/programs/local/LocalServer.cpp
+++ b/dbms/programs/local/LocalServer.cpp
@@ -73,6 +73,7 @@ void LocalServer::initialize(Poco::Util::Application & self)
 
     if (config().has("logger") || config().has("logger.level") || config().has("logger.log"))
     {
+        // sensitive data rules are not used here
         buildLoggers(config(), logger());
     }
     else
diff --git a/dbms/programs/odbc-bridge/ODBCBridge.cpp b/dbms/programs/odbc-bridge/ODBCBridge.cpp
index cf265eb6abb..214d9f75328 100644
--- a/dbms/programs/odbc-bridge/ODBCBridge.cpp
+++ b/dbms/programs/odbc-bridge/ODBCBridge.cpp
@@ -124,6 +124,7 @@ void ODBCBridge::initialize(Application & self)
     config().setString("logger", "ODBCBridge");
 
     buildLoggers(config(), logger());
+
     log = &logger();
     hostname = config().getString("listen-host", "localhost");
     port = config().getUInt("http-port");
@@ -162,6 +163,12 @@ int ODBCBridge::main(const std::vector<std::string> & /*args*/)
     context = std::make_shared<Context>(Context::createGlobal());
     context->makeGlobalContext();
 
+    if (config().has("query_masking_rules"))
+    {
+        context->setSensitiveDataMasker(std::make_unique<SensitiveDataMasker>(config(), "query_masking_rules"));
+        setLoggerSensitiveDataMasker(logger(), context->getSensitiveDataMasker());
+    }
+
     auto server = Poco::Net::HTTPServer(
         new HandlerFactory("ODBCRequestHandlerFactory-factory", keep_alive_timeout, context), server_pool, socket, http_params);
     server.start();
diff --git a/dbms/programs/server/Server.cpp b/dbms/programs/server/Server.cpp
index 3d50466df84..1ca29c40745 100644
--- a/dbms/programs/server/Server.cpp
+++ b/dbms/programs/server/Server.cpp
@@ -269,7 +269,11 @@ int Server::main(const std::vector<std::string> & /*args*/)
           *  table engines could use Context on destroy.
           */
         LOG_INFO(log, "Shutting down storages.");
+
+        // global_context is the owner of sensitive_data_masker, which will be destoyed after global_context->shutdown() call
+        setLoggerSensitiveDataMasker(logger(), nullptr);
         global_context->shutdown();
+
         LOG_DEBUG(log, "Shutted down storages.");
 
         /** Explicitly destroy Context. It is more convenient than in destructor of Server, because logger is still available.
@@ -399,6 +403,12 @@ int Server::main(const std::vector<std::string> & /*args*/)
 
     /// Initialize main config reloader.
     std::string include_from_path = config().getString("include_from", "/etc/metrika.xml");
+
+    if (config().has("query_masking_rules"))
+    {
+        global_context->setSensitiveDataMasker(std::make_unique<SensitiveDataMasker>(config(), "query_masking_rules"));
+    }
+
     auto main_config_reloader = std::make_unique<ConfigReloader>(config_path,
         include_from_path,
         config().getString("path", ""),
@@ -407,6 +417,10 @@ int Server::main(const std::vector<std::string> & /*args*/)
         [&](ConfigurationPtr config)
         {
             buildLoggers(*config, logger());
+            if (auto masker = global_context->getSensitiveDataMasker())
+            {
+                setLoggerSensitiveDataMasker(logger(), masker);
+            }
             global_context->setClustersConfig(config);
             global_context->setMacros(std::make_unique<Macros>(*config, "macros"));
         },
diff --git a/dbms/programs/server/config.xml b/dbms/programs/server/config.xml
index 154ebf6c35e..699c18638c5 100644
--- a/dbms/programs/server/config.xml
+++ b/dbms/programs/server/config.xml
@@ -410,6 +410,20 @@
       -->
     <format_schema_path>/var/lib/clickhouse/format_schemas/</format_schema_path>
 
+
+    <!-- Uncomment to use query masking rules.
+        name - name for the rule (optional)
+        regexp - RE2 compatible regular expression (mandatory)
+        replace - substitution string for sensitive data (optional, by default - six asterisks)
+    <query_masking_rules>
+        <rule>
+            <name>hide SSN</name>
+            <regexp>(^|\D)\d{3}-\d{2}-\d{4}($|\D)</regexp>
+            <replace>000-00-0000</replace>
+        </rule>
+    </query_masking_rules>
+    -->
+
     <!-- Uncomment to disable ClickHouse internal DNS caching. -->
     <!-- <disable_internal_dns_cache>1</disable_internal_dns_cache> -->
 </yandex>
diff --git a/dbms/src/Common/ProfileEvents.cpp b/dbms/src/Common/ProfileEvents.cpp
index 7059e02d76c..3489b17178f 100644
--- a/dbms/src/Common/ProfileEvents.cpp
+++ b/dbms/src/Common/ProfileEvents.cpp
@@ -44,6 +44,8 @@
     M(NetworkSendElapsedMicroseconds, "") \
     M(ThrottlerSleepMicroseconds, "Total time a query was sleeping to conform the 'max_network_bandwidth' setting.") \
     \
+    M(QueryMaskingRulesMatch, "Number of times query masking rules was successfully matched.") \
+    \
     M(ReplicatedPartFetches, "Number of times a data part was downloaded from replica of a ReplicatedMergeTree table.") \
     M(ReplicatedPartFailedFetches, "") \
     M(ObsoleteReplicatedParts, "") \
diff --git a/dbms/src/Common/SensitiveDataMasker.cpp b/dbms/src/Common/SensitiveDataMasker.cpp
new file mode 100644
index 00000000000..488c0be4245
--- /dev/null
+++ b/dbms/src/Common/SensitiveDataMasker.cpp
@@ -0,0 +1,166 @@
+#include "SensitiveDataMasker.h"
+
+#include <set>
+#include <string>
+#include <atomic>
+
+#include <re2/re2.h>
+#include <re2/stringpiece.h>
+
+#include <Poco/Util/AbstractConfiguration.h>
+
+#include <common/logger_useful.h>
+
+#include <Common/Exception.h>
+#include <Common/StringUtils/StringUtils.h>
+
+#ifndef NDEBUG
+#    include <iostream>
+#endif
+
+namespace DB
+{
+namespace ErrorCodes
+{
+    extern const int CANNOT_COMPILE_REGEXP;
+    extern const int NO_ELEMENTS_IN_CONFIG;
+    extern const int INVALID_CONFIG_PARAMETER;
+}
+
+class SensitiveDataMasker::MaskingRule
+{
+private:
+    const std::string name;
+    const std::string replacement_string;
+    const std::string regexp_string;
+
+    const RE2 regexp;
+    const re2::StringPiece replacement;
+
+    mutable std::atomic<std::uint64_t> matches_count = 0;
+
+public:
+    //* TODO: option with hyperscan? https://software.intel.com/en-us/articles/why-and-how-to-replace-pcre-with-hyperscan
+    // re2::set should also work quite fast, but it doesn't return the match position, only which regexp was matched
+
+    MaskingRule(const std::string & name, const std::string & _regexp_string, const std::string & _replacement_string)
+        : name(name)
+        , replacement_string(_replacement_string)
+        , regexp_string(_regexp_string)
+        , regexp(regexp_string, RE2::Quiet)
+        , replacement(replacement_string)
+    {
+        if (!regexp.ok())
+            throw DB::Exception(
+                "SensitiveDataMasker: cannot compile re2: " + _regexp_string + ", error: " + regexp.error()
+                    + ". Look at https://github.com/google/re2/wiki/Syntax for reference.",
+                DB::ErrorCodes::CANNOT_COMPILE_REGEXP);
+    }
+    int apply(std::string & data) const
+    {
+        auto m = RE2::GlobalReplace(&data, regexp, replacement);
+        matches_count += m;
+        return m;
+    }
+
+    const std::string & getName() const { return name; }
+    const std::string & getReplacementString() const { return replacement_string; }
+    uint64_t getMatchesCount() const { return matches_count; }
+};
+
+SensitiveDataMasker::SensitiveDataMasker(const Poco::Util::AbstractConfiguration & config, const std::string & config_prefix)
+{
+    Poco::Util::AbstractConfiguration::Keys keys;
+    config.keys(config_prefix, keys);
+    Logger * logger = &Logger::get("SensitiveDataMaskerConfigRead");
+
+    std::set<std::string> used_names;
+
+    for (const auto & rule : keys)
+    {
+        if (startsWith(rule, "rule"))
+        {
+            auto rule_config_prefix = config_prefix + "." + rule;
+
+            auto rule_name = config.getString(rule_config_prefix + ".name", rule_config_prefix);
+
+            if (used_names.count(rule_name) == 0)
+            {
+                used_names.insert(rule_name);
+            }
+            else
+            {
+                throw Exception(
+                    "query_masking_rules configuration contains more than one rule named '" + rule_name + "'.",
+                    ErrorCodes::INVALID_CONFIG_PARAMETER);
+            }
+
+            auto regexp = config.getString(rule_config_prefix + ".regexp", "");
+
+            if (regexp == "")
+            {
+                throw Exception(
+                    "query_masking_rules configuration, rule '" + rule_name + "' has no <regexp> node or <regexp> is empty.",
+                    ErrorCodes::NO_ELEMENTS_IN_CONFIG);
+            }
+
+            auto replace = config.getString(rule_config_prefix + ".replace", "******");
+
+            try
+            {
+                addMaskingRule(rule_name, regexp, replace);
+            }
+            catch (DB::Exception & e)
+            {
+                e.addMessage("while adding query masking rule '" + rule_name + "'.");
+                throw;
+            }
+        }
+        else
+        {
+            LOG_WARNING(logger, "Unused param " << config_prefix << '.' << rule);
+        }
+    }
+    auto rules_count = this->rulesCount();
+    if (rules_count > 0)
+    {
+        LOG_INFO(logger, rules_count << " query masking rules loaded.");
+    }
+}
+
+SensitiveDataMasker::~SensitiveDataMasker() {}
+
+void SensitiveDataMasker::addMaskingRule(
+    const std::string & name, const std::string & regexp_string, const std::string & replacement_string)
+{
+    all_masking_rules.push_back(std::make_unique<MaskingRule>(name, regexp_string, replacement_string));
+}
+
+
+int SensitiveDataMasker::wipeSensitiveData(std::string & data) const
+{
+    int matches = 0;
+    for (auto & rule : all_masking_rules)
+    {
+        matches += rule->apply(data);
+    }
+    return matches;
+}
+
+#ifndef NDEBUG
+void SensitiveDataMasker::printStats()
+{
+    for (auto & rule : all_masking_rules)
+    {
+        std::cout << rule->getName() << " (replacement to " << rule->getReplacementString() << ") matched " << rule->getMatchesCount()
+                  << " times" << std::endl;
+    }
+}
+#endif
+
+unsigned long SensitiveDataMasker::rulesCount() const
+{
+    return all_masking_rules.size();
+}
+
+}
diff --git a/dbms/src/Common/SensitiveDataMasker.h b/dbms/src/Common/SensitiveDataMasker.h
new file mode 100644
index 00000000000..02e86976d02
--- /dev/null
+++ b/dbms/src/Common/SensitiveDataMasker.h
@@ -0,0 +1,35 @@
+#pragma once
+
+#include <memory>
+#include <vector>
+
+namespace Poco
+{
+namespace Util
+{
+    class AbstractConfiguration;
+}
+}
+
+namespace DB
+{
+class SensitiveDataMasker
+{
+private:
+    class MaskingRule;
+    std::vector<std::unique_ptr<MaskingRule>> all_masking_rules;
+
+public:
+    SensitiveDataMasker(const Poco::Util::AbstractConfiguration & config, const std::string & config_prefix);
+    ~SensitiveDataMasker();
+    void addMaskingRule(const std::string & name, const std::string & regexp_string, const std::string & replacement_string);
+    int wipeSensitiveData(std::string & data) const;
+
+#ifndef NDEBUG
+    void printStats();
+#endif
+
+    unsigned long rulesCount() const;
+};
+
+};
diff --git a/dbms/src/Common/tests/gtest_sensitive_data_masker.cpp b/dbms/src/Common/tests/gtest_sensitive_data_masker.cpp
new file mode 100644
index 00000000000..d79b7b9932c
--- /dev/null
+++ b/dbms/src/Common/tests/gtest_sensitive_data_masker.cpp
@@ -0,0 +1,228 @@
+#include <Common/Exception.h>
+#include <Common/SensitiveDataMasker.h>
+#include <Poco/AutoPtr.h>
+#include <Poco/Util/XMLConfiguration.h>
+#include <Poco/XML/XMLException.h>
+
+#pragma GCC diagnostic ignored "-Wsign-compare"
+#ifdef __clang__
+#    pragma clang diagnostic ignored "-Wzero-as-null-pointer-constant"
+#    pragma clang diagnostic ignored "-Wundef"
+#endif
+
+#include <gtest/gtest.h>
+
+
+namespace DB
+{
+namespace ErrorCodes
+{
+extern const int CANNOT_COMPILE_REGEXP;
+extern const int NO_ELEMENTS_IN_CONFIG;
+extern const int INVALID_CONFIG_PARAMETER;
+}
+};
+
+
+TEST(Common, SensitiveDataMasker)
+{
+
+    Poco::AutoPtr<Poco::Util::XMLConfiguration> empty_xml_config = new Poco::Util::XMLConfiguration();
+    DB::SensitiveDataMasker masker(*empty_xml_config , "");
+    masker.addMaskingRule("all a letters", "a+", "--a--");
+    masker.addMaskingRule("all b letters", "b+", "--b--");
+    masker.addMaskingRule("all d letters", "d+", "--d--");
+    masker.addMaskingRule("all x letters", "x+", "--x--");
+    masker.addMaskingRule("rule \"d\" result", "--d--", "*****"); // RE2 regexps are applied one-by-one in order
+    std::string x = "aaaaaaaaaaaaa   bbbbbbbbbb cccc aaaaaaaaaaaa d ";
+    EXPECT_EQ(masker.wipeSensitiveData(x), 5);
+    EXPECT_EQ(x, "--a--   --b-- cccc --a-- ***** ");
+#ifndef NDEBUG
+    masker.printStats();
+#endif
+    EXPECT_EQ(masker.wipeSensitiveData(x), 3);
+    EXPECT_EQ(x, "----a----   ----b---- cccc ----a---- ***** ");
+#ifndef NDEBUG
+    masker.printStats();
+#endif
+
+    DB::SensitiveDataMasker masker2(*empty_xml_config , "");
+    masker2.addMaskingRule("hide root password", "qwerty123", "******");
+    masker2.addMaskingRule("hide SSN", "[0-9]{3}-[0-9]{2}-[0-9]{4}", "000-00-0000");
+    masker2.addMaskingRule("hide email", "[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}", "hidden@hidden.test");
+
+    std::string query = "SELECT id FROM mysql('localhost:3308', 'database', 'table', 'root', 'qwerty123') WHERE ssn='123-45-6789' or "
+                        "email='JonhSmith@secret.domain.test'";
+    EXPECT_EQ(masker2.wipeSensitiveData(query), 3);
+    EXPECT_EQ(
+        query,
+        "SELECT id FROM mysql('localhost:3308', 'database', 'table', 'root', '******') WHERE "
+        "ssn='000-00-0000' or email='hidden@hidden.test'");
+
+
+#ifndef NDEBUG
+    // simple benchmark
+    auto start = std::chrono::high_resolution_clock::now();
+    constexpr unsigned long int iterations = 200000;
+    for (int i = 0; i < iterations; ++i)
+    {
+        std::string query2 = "SELECT id FROM mysql('localhost:3308', 'database', 'table', 'root', 'qwerty123') WHERE ssn='123-45-6789' or "
+                             "email='JonhSmith@secret.domain.test'";
+        masker2.wipeSensitiveData(query2);
+    }
+    auto finish = std::chrono::high_resolution_clock::now();
+    std::chrono::duration<double> elapsed = finish - start;
+    std::cout << "Elapsed time: " << elapsed.count() << "s per " << iterations <<" calls (" << elapsed.count() * 1000000 / iterations << "µs per call)"
+              << std::endl;
+    // I have: "Elapsed time: 3.44022s per 200000 calls (17.2011µs per call)"
+    masker2.printStats();
+#endif
+
+    DB::SensitiveDataMasker maskerbad(*empty_xml_config , "");
+
+    // gtest has not good way to check exception content, so just do it manually (see https://github.com/google/googletest/issues/952 )
+    try
+    {
+        maskerbad.addMaskingRule("bad regexp", "**", "");
+        ADD_FAILURE() << "addMaskingRule() should throw an error" << std::endl;
+    }
+    catch (DB::Exception & e)
+    {
+        EXPECT_EQ(
+            std::string(e.what()),
+            "SensitiveDataMasker: cannot compile re2: **, error: no argument for repetition operator: *. Look at "
+            "https://github.com/google/re2/wiki/Syntax for reference.");
+        EXPECT_EQ(e.code(), DB::ErrorCodes::CANNOT_COMPILE_REGEXP);
+    }
+    /* catch (...) { // not needed, gtest will react unhandled exception
+        FAIL() << "ERROR: Unexpected exception thrown: " << std::current_exception << std::endl; // std::current_exception is part of C++11x
+    } */
+
+    EXPECT_EQ(maskerbad.rulesCount(), 0);
+    EXPECT_EQ(maskerbad.wipeSensitiveData(x), 0);
+
+    {
+        std::istringstream xml_isteam(R"END(<?xml version="1.0"?>
+<clickhouse>
+    <query_masking_rules>
+        <rule>
+            <name>hide SSN</name><!-- by default: it will use xml path, like query_masking_rules.rule[1] -->
+            <regexp>[0-9]{3}-[0-9]{2}-[0-9]{4}</regexp><!-- mandatory -->
+            <replace>000-00-0000</replace><!-- by default - six asterisks (******) -->
+        </rule>
+        <rule>
+            <name>hide root password</name>
+            <regexp>qwerty123</regexp>
+        </rule>
+        <rule>
+            <regexp>(?i)Ivan</regexp>
+            <replace>John</replace>
+        </rule>
+        <rule>
+            <regexp>(?i)Petrov</regexp>
+            <replace>Doe</replace>
+        </rule>
+        <rule>
+            <name>hide email</name>
+            <regexp>(?i)[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}</regexp>
+            <replace>hidden@hidden.test</replace>
+        </rule>
+        <rule>
+            <name>remove selects to bad_words table</name>
+            <regexp>^.*bad_words.*$</regexp>
+            <replace>[QUERY IS CENSORED]</replace>
+        </rule>
+    </query_masking_rules>
+</clickhouse>)END");
+
+        Poco::AutoPtr<Poco::Util::XMLConfiguration> xml_config = new Poco::Util::XMLConfiguration(xml_isteam);
+        DB::SensitiveDataMasker masker_xml_based(*xml_config, "query_masking_rules");
+        std::string top_secret = "The e-mail of IVAN PETROV is kotik1902@sdsdf.test, and the password is qwerty123";
+        EXPECT_EQ(masker_xml_based.wipeSensitiveData(top_secret), 4);
+        EXPECT_EQ(top_secret, "The e-mail of John Doe is hidden@hidden.test, and the password is ******");
+
+        top_secret = "SELECT * FROM bad_words";
+        EXPECT_EQ(masker_xml_based.wipeSensitiveData(top_secret), 1);
+        EXPECT_EQ(top_secret, "[QUERY IS CENSORED]");
+
+#ifndef NDEBUG
+        masker_xml_based.printStats();
+#endif
+    }
+
+    try
+    {
+        std::istringstream xml_isteam_bad(R"END(<?xml version="1.0"?>
+<clickhouse>
+    <query_masking_rules>
+        <rule>
+            <name>test</name>
+            <regexp>abc</regexp>
+        </rule>
+        <rule>
+            <name>test</name>
+            <regexp>abc</regexp>
+        </rule>
+    </query_masking_rules>
+</clickhouse>)END");
+        Poco::AutoPtr<Poco::Util::XMLConfiguration> xml_config = new Poco::Util::XMLConfiguration(xml_isteam_bad);
+        DB::SensitiveDataMasker masker_xml_based_exception_check(*xml_config, "query_masking_rules");
+
+        ADD_FAILURE() << "XML should throw an error on bad XML" << std::endl;
+    }
+    catch (DB::Exception & e)
+    {
+        EXPECT_EQ(
+            std::string(e.what()),
+            "query_masking_rules configuration contains more than one rule named 'test'.");
+        EXPECT_EQ(e.code(), DB::ErrorCodes::INVALID_CONFIG_PARAMETER);
+    }
+
+
+    try
+    {
+        std::istringstream xml_isteam_bad(R"END(<?xml version="1.0"?>
+<clickhouse>
+    <query_masking_rules>
+        <rule><name>test</name></rule>
+    </query_masking_rules>
+</clickhouse>)END");
+
+        Poco::AutoPtr<Poco::Util::XMLConfiguration> xml_config = new Poco::Util::XMLConfiguration(xml_isteam_bad);
+        DB::SensitiveDataMasker masker_xml_based_exception_check(*xml_config, "query_masking_rules");
+
+        ADD_FAILURE() << "XML should throw an error on bad XML" << std::endl;
+    }
+    catch (DB::Exception & e)
+    {
+        EXPECT_EQ(
+            std::string(e.what()),
+            "query_masking_rules configuration, rule 'test' has no <regexp> node or <regexp> is empty.");
+        EXPECT_EQ(e.code(), DB::ErrorCodes::NO_ELEMENTS_IN_CONFIG);
+    }
+
+
+    try
+    {
+        std::istringstream xml_isteam_bad(R"END(<?xml version="1.0"?>
+<clickhouse>
+    <query_masking_rules>
+        <rule><name>test</name><regexp>())(</regexp></rule>
+    </query_masking_rules>
+</clickhouse>)END");
+
+        Poco::AutoPtr<Poco::Util::XMLConfiguration> xml_config = new Poco::Util::XMLConfiguration(xml_isteam_bad);
+        DB::SensitiveDataMasker masker_xml_based_exception_check(*xml_config, "query_masking_rules");
+
+        ADD_FAILURE() << "XML should throw an error on bad XML" << std::endl;
+    }
+    catch (DB::Exception & e)
+    {
+        EXPECT_EQ(
+            std::string(e.message()),
+            "SensitiveDataMasker: cannot compile re2: ())(, error: missing ): ())(. Look at https://github.com/google/re2/wiki/Syntax for reference.: while adding query masking rule 'test'."
+        );
+        EXPECT_EQ(e.code(), DB::ErrorCodes::CANNOT_COMPILE_REGEXP);
+    }
+
+}
diff --git a/dbms/src/Interpreters/Context.cpp b/dbms/src/Interpreters/Context.cpp
index bf779ada6b4..13f213392e3 100644
--- a/dbms/src/Interpreters/Context.cpp
+++ b/dbms/src/Interpreters/Context.cpp
@@ -146,6 +146,8 @@ struct ContextShared
     std::unique_ptr<DDLWorker> ddl_worker;                  /// Process ddl commands from zk.
     /// Rules for selecting the compression settings, depending on the size of the part.
     mutable std::unique_ptr<CompressionCodecSelector> compression_codec_selector;
+    /// Allows to remove sensitive data from queries using set of regexp-based rules
+    std::unique_ptr<SensitiveDataMasker> sensitive_data_masker;
     std::optional<MergeTreeSettings> merge_tree_settings; /// Settings of MergeTree* engines.
     size_t max_table_size_to_drop = 50000000000lu;          /// Protects MergeTree tables from accidental DROP (50GB by default)
     size_t max_partition_size_to_drop = 50000000000lu;      /// Protects MergeTree partitions from accidental DROP (50GB by default)
@@ -285,6 +287,7 @@ struct ContextShared
         background_pool.reset();
         schedule_pool.reset();
         ddl_worker.reset();
+        sensitive_data_masker.reset();
     }
 
 private:
@@ -522,6 +525,19 @@ String Context::getUserFilesPath() const
     return shared->user_files_path;
 }
 
+void Context::setSensitiveDataMasker(std::unique_ptr<SensitiveDataMasker> sensitive_data_masker)
+{
+    if (sensitive_data_masker->rulesCount() > 0) {
+        auto lock = getLock();
+        shared->sensitive_data_masker = std::move(sensitive_data_masker);
+    }
+}
+
+SensitiveDataMasker * Context::getSensitiveDataMasker() const
+{
+    return shared->sensitive_data_masker.get();
+}
+
 void Context::setPath(const String & path)
 {
     auto lock = getLock();
diff --git a/dbms/src/Interpreters/Context.h b/dbms/src/Interpreters/Context.h
index 44547f97ef2..ce9661334a3 100644
--- a/dbms/src/Interpreters/Context.h
+++ b/dbms/src/Interpreters/Context.h
@@ -11,6 +11,7 @@
 #include <Common/MultiVersion.h>
 #include <Common/ThreadPool.h>
 #include "config_core.h"
+#include <Common/SensitiveDataMasker.h>
 #include <Storages/IStorage_fwd.h>
 #include <atomic>
 #include <chrono>
@@ -172,6 +173,9 @@ public:
     String getFlagsPath() const;
     String getUserFilesPath() const;
 
+    void setSensitiveDataMasker(std::unique_ptr<SensitiveDataMasker> sensitive_data_masker);
+    SensitiveDataMasker * getSensitiveDataMasker() const;
+
     void setPath(const String & path);
     void setTemporaryPath(const String & path);
     void setFlagsPath(const String & path);
diff --git a/dbms/src/Interpreters/executeQuery.cpp b/dbms/src/Interpreters/executeQuery.cpp
index b001c9bcb0a..66e67321777 100644
--- a/dbms/src/Interpreters/executeQuery.cpp
+++ b/dbms/src/Interpreters/executeQuery.cpp
@@ -34,6 +34,13 @@
 #include <Processors/Transforms/MaterializingTransform.h>
 #include <Processors/Formats/IOutputFormat.h>
 
+#include <Common/ProfileEvents.h>
+
+namespace ProfileEvents
+{
+    extern const Event QueryMaskingRulesMatch;
+}
+
 namespace DB
 {
 
@@ -54,7 +61,6 @@ static void checkASTSizeLimits(const IAST & ast, const Settings & settings)
         ast.checkSize(settings.max_ast_elements);
 }
 
-
 /// NOTE This is wrong in case of single-line comments and in case of multiline string literals.
 static String joinLines(const String & query)
 {
@@ -64,6 +70,26 @@ static String joinLines(const String & query)
 }
 
 
+static String prepareQueryForLogging(const String & query, Context & context)
+{
+    String res = query;
+    // cropping is cheap and can reduce the amount of work for wipeSensitiveData
+    // side effect: if the query had long string with sensitive data which were removed,
+    // we will store less than log_queries_cut_to_length in logs
+    res = res.substr(0, context.getSettingsRef().log_queries_cut_to_length);
+
+    if (auto masker = context.getSensitiveDataMasker())
+    {
+        auto matches = masker->wipeSensitiveData(res);
+        if (matches > 0)
+        {
+            ProfileEvents::increment(ProfileEvents::QueryMaskingRulesMatch, matches);
+        }
+    }
+    return res;
+}
+
+
 /// Log query into text log (not into system table).
 static void logQuery(const String & query, const Context & context, bool internal)
 {
@@ -111,7 +137,7 @@ static void logException(Context & context, QueryLogElement & elem)
 }
 
 
-static void onExceptionBeforeStart(const String & query, Context & context, time_t current_time)
+static void onExceptionBeforeStart(const String & query_for_logging, Context & context, time_t current_time)
 {
     /// Exception before the query execution.
     context.getQuota().addError();
@@ -126,7 +152,7 @@ static void onExceptionBeforeStart(const String & query, Context & context, time
     elem.event_time = current_time;
     elem.query_start_time = current_time;
 
-    elem.query = query.substr(0, settings.log_queries_cut_to_length);
+    elem.query = query_for_logging;
     elem.exception = getCurrentExceptionMessage(false);
 
     elem.client_info = context.getClientInfo();
@@ -192,10 +218,12 @@ static std::tuple<ASTPtr, BlockIO> executeQueryImpl(
     {
         /// Anyway log the query.
         String query = String(begin, begin + std::min(end - begin, static_cast<ptrdiff_t>(max_query_size)));
-        logQuery(query.substr(0, settings.log_queries_cut_to_length), context, internal);
+
+        auto query_for_logging = prepareQueryForLogging(query, context);
+        logQuery(query_for_logging, context, internal);
 
         if (!internal)
-            onExceptionBeforeStart(query, context, current_time);
+            onExceptionBeforeStart(query_for_logging, context, current_time);
 
         throw;
     }
@@ -205,6 +233,8 @@ static std::tuple<ASTPtr, BlockIO> executeQueryImpl(
     BlockIO res;
     QueryPipeline & pipeline = res.pipeline;
 
+    String query_for_logging = "";
+
     try
     {
         /// Replace ASTQueryParameter with ASTLiteral for prepared statements.
@@ -217,7 +247,9 @@ static std::tuple<ASTPtr, BlockIO> executeQueryImpl(
             query = serializeAST(*ast);
         }
 
-        logQuery(query.substr(0, settings.log_queries_cut_to_length), context, internal);
+        query_for_logging = prepareQueryForLogging(query, context);
+
+        logQuery(query_for_logging, context, internal);
 
         /// Check the limits.
         checkASTSizeLimits(*ast, settings);
@@ -231,7 +263,8 @@ static std::tuple<ASTPtr, BlockIO> executeQueryImpl(
         ProcessList::EntryPtr process_list_entry;
         if (!internal && !ast->as<ASTShowProcesslistQuery>())
         {
-            process_list_entry = context.getProcessList().insert(query, ast.get(), context);
+            /// processlist also has query masked now, to avoid secrets leaks though SHOW PROCESSLIST by other users.
+            process_list_entry = context.getProcessList().insert(query_for_logging, ast.get(), context);
             context.setProcessListElement(&process_list_entry->get());
         }
 
@@ -318,7 +351,7 @@ static std::tuple<ASTPtr, BlockIO> executeQueryImpl(
             elem.event_time = current_time;
             elem.query_start_time = current_time;
 
-            elem.query = query.substr(0, settings.log_queries_cut_to_length);
+            elem.query = query_for_logging;
 
             elem.client_info = context.getClientInfo();
 
@@ -462,7 +495,12 @@ static std::tuple<ASTPtr, BlockIO> executeQueryImpl(
     catch (...)
     {
         if (!internal)
-            onExceptionBeforeStart(query, context, current_time);
+        {
+            if (query_for_logging.empty())
+                query_for_logging = prepareQueryForLogging(query, context);
+
+            onExceptionBeforeStart(query_for_logging, context, current_time);
+        }
 
         throw;
     }
diff --git a/dbms/tests/queries/0_stateless/00956_sensitive_data_masking.reference b/dbms/tests/queries/0_stateless/00956_sensitive_data_masking.reference
new file mode 100644
index 00000000000..10856627eac
--- /dev/null
+++ b/dbms/tests/queries/0_stateless/00956_sensitive_data_masking.reference
@@ -0,0 +1,10 @@
+1
+2
+3
+4
+5
+5.1
+6
+7
+8
+finish
diff --git a/dbms/tests/queries/0_stateless/00956_sensitive_data_masking.sh b/dbms/tests/queries/0_stateless/00956_sensitive_data_masking.sh
new file mode 100755
index 00000000000..ef66d30581a
--- /dev/null
+++ b/dbms/tests/queries/0_stateless/00956_sensitive_data_masking.sh
@@ -0,0 +1,110 @@
+#!/usr/bin/env bash
+
+# Get all server logs
+export CLICKHOUSE_CLIENT_SERVER_LOGS_LEVEL="trace"
+#export CLICKHOUSE_BINARY='../../../../build-vscode/Debug/dbms/programs/clickhouse'
+#export CLICKHOUSE_PORT_TCP=59000
+#export CLICKHOUSE_CLIENT_BINARY='../../../../cmake-build-debug/dbms/programs/clickhouse client'
+
+CURDIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
+. $CURDIR/../shell_config.sh
+
+cur_name=$(basename "${BASH_SOURCE[0]}")
+tmp_file=${CLICKHOUSE_TMP}/$cur_name"_server.logs"
+
+rm -f $tmp_file >/dev/null 2>&1
+echo 1
+# normal execution
+$CLICKHOUSE_CLIENT \
+  --query="SELECT 'find_me_TOPSECRET=TOPSECRET' FROM numbers(1) FORMAT Null" \
+  --log_queries=1 --ignore-error --multiquery >$tmp_file 2>&1
+
+grep 'find_me_\[hidden\]' $tmp_file >/dev/null || echo 'fail 1a'
+grep 'TOPSECRET' $tmp_file && echo 'fail 1b'
+
+rm -f $tmp_file >/dev/null 2>&1
+echo 2
+# failure at parsing stage
+echo "SELECT 'find_me_TOPSECRET=TOPSECRET' FRRRROM numbers" | ${CLICKHOUSE_CURL} -sSg ${CLICKHOUSE_URL} -d @- >$tmp_file 2>&1
+
+#cat $tmp_file
+
+## can't be checked on client side!
+# grep 'find_me_\[hidden\]' $tmp_file >/dev/null || echo 'fail 2a'
+grep 'TOPSECRET' $tmp_file && echo 'fail 2b'
+
+rm -f $tmp_file >/dev/null 2>&1
+echo 3
+# failure at before query start
+$CLICKHOUSE_CLIENT \
+  --query="SELECT 'find_me_TOPSECRET=TOPSECRET' FROM non_existing_table FORMAT Null" \
+  --log_queries=1 --ignore-error --multiquery >$tmp_file 2>&1
+
+grep 'find_me_\[hidden\]' $tmp_file >/dev/null || echo 'fail 3a'
+grep 'TOPSECRET' $tmp_file && echo 'fail 3b'
+
+rm -f $tmp_file >/dev/null 2>&1
+echo 4
+# failure at the end of query
+$CLICKHOUSE_CLIENT \
+  --query="SELECT 'find_me_TOPSECRET=TOPSECRET', intDiv( 100, number - 10) FROM numbers(11) FORMAT Null" \
+  --log_queries=1 --ignore-error --max_block_size=2 --multiquery >$tmp_file 2>&1
+
+grep 'find_me_\[hidden\]' $tmp_file >/dev/null || echo 'fail 4a'
+grep 'TOPSECRET' $tmp_file && echo 'fail 4b'
+
+echo 5
+# run in background
+bash -c "$CLICKHOUSE_CLIENT \
+  --query=\"select sleepEachRow(0.5) from numbers(4) where ignore('find_me_TOPSECRET=TOPSECRET')=0 and ignore('fwerkh_that_magic_string_make_me_unique') = 0 FORMAT Null\" \
+  --log_queries=1 --ignore-error --multiquery 2>&1 | grep TOPSECRET" &
+
+sleep 0.1
+
+# $CLICKHOUSE_CLIENT --query='SHOW PROCESSLIST'
+
+rm -f $tmp_file >/dev/null 2>&1
+echo '5.1'
+# check that executing query doesn't expose secrets in processlist
+$CLICKHOUSE_CLIENT --query="SHOW PROCESSLIST" --log_queries=0 >$tmp_file 2>&1
+
+grep 'fwerkh_that_magic_string_make_me_unique' $tmp_file >/dev/null || echo 'fail 5a'
+( grep 'fwerkh_that_magic_string_make_me_unique' $tmp_file | grep 'find_me_\[hidden\]' $tmp_file >/dev/null ) || echo 'fail 5b'
+grep 'TOPSECRET' $tmp_file && echo 'fail 5c'
+
+wait
+
+
+# instead of disabling send_logs_level=trace (enabled globally for that test) - redir it's output to /dev/null
+$CLICKHOUSE_CLIENT \
+  --server_logs_file=/dev/null \
+  --query="system flush logs"
+
+
+echo 6
+# check events count properly increments
+$CLICKHOUSE_CLIENT \
+  --server_logs_file=/dev/null \
+  --query="select * from (select sum(value) as matches from system.events where event='QueryMaskingRulesMatch') where matches < 5"
+
+echo 7
+# and finally querylog
+$CLICKHOUSE_CLIENT \
+  --server_logs_file=/dev/null \
+  --query="select * from system.query_log where event_time>now() - 10 and query like '%TOPSECRET%';"
+
+
+rm -f $tmp_file >/dev/null 2>&1
+echo 8
+$CLICKHOUSE_CLIENT \
+   --query="drop table if exists sensetive; create table sensitive ( id UInt64, date Date, value1 String, value2 UInt64) Engine=MergeTree ORDER BY id PARTITION BY date;
+insert into sensitive select number as id, toDate('2019-01-01') as date, 'abcd' as value1, rand() as valuer from numbers(10000);
+insert into sensitive select number as id, toDate('2019-01-01') as date, 'find_me_TOPSECRET=TOPSECRET' as value1, rand() as valuer from numbers(10);
+insert into sensitive select number as id, toDate('2019-01-01') as date, 'abcd' as value1, rand() as valuer from numbers(10000);
+select * from sensitive WHERE value1 = 'find_me_TOPSECRET=TOPSECRET' FORMAT Null;
+drop table sensetive;" --log_queries=1 --ignore-error --multiquery >$tmp_file 2>&1
+
+grep 'find_me_\[hidden\]' $tmp_file >/dev/null || echo 'fail 8a'
+grep 'TOPSECRET' $tmp_file && echo 'fail 8b'
+
+echo 'finish'
\ No newline at end of file
diff --git a/docs/en/operations/server_settings/settings.md b/docs/en/operations/server_settings/settings.md
index 2f87233e6a3..5d3e0d93ab6 100644
--- a/docs/en/operations/server_settings/settings.md
+++ b/docs/en/operations/server_settings/settings.md
@@ -554,6 +554,36 @@ If the table doesn't exist, ClickHouse will create it. If the structure of the q
 </query_log>
 ```
 
+## query_masking_rules
+
+Regexp-based rules, which will be applied to queries before storing them in server logs,
+`system.query_log` table, `system.processes` table. That allows preventing
+sensitive data leakage from SQL queries (like names / emails / personal
+identifiers / credit card numbers etc) to logs.
+
+**Example**
+
+```xml
+<query_masking_rules>
+    <rule>
+        <name>hide SSN</name>
+        <regexp>(^|\D)\d{3}-\d{2}-\d{4}($|\D)</regexp>
+        <replace>000-00-0000</replace>
+    </rule>
+</query_masking_rules>
+```
+
+Config fields:
+- `name` - name for the rule (optional)
+- `regexp` - RE2 compatible regular expression (mandatory)
+- `replace` - substitution string for sensitive data (optional, by default - six asterisks)
+
+The masking rules are applied on whole query (to prevent leaks of sensitive data from malformed / non parsable queries).
+
+`system.events` table have counter `QueryMaskingRulesMatch` which have overall number of query masking rules matches.
+
+For distributed queries each server have to be configured separately, otherwise subquries passed to other
+nodes will be stored without masking.
 
 ## remote_servers
 
diff --git a/libs/libdaemon/src/BaseDaemon.cpp b/libs/libdaemon/src/BaseDaemon.cpp
index b40f00a700f..f3508b3156b 100644
--- a/libs/libdaemon/src/BaseDaemon.cpp
+++ b/libs/libdaemon/src/BaseDaemon.cpp
@@ -652,6 +652,7 @@ void BaseDaemon::initialize(Application & self)
             throw Poco::Exception("Cannot change directory to /tmp");
     }
 
+    // sensitive data masking rules are not used here
     buildLoggers(config(), logger());
 
     if (is_daemon)
diff --git a/libs/libloggers/loggers/Loggers.cpp b/libs/libloggers/loggers/Loggers.cpp
index bc53cff27aa..0269fe0787f 100644
--- a/libs/libloggers/loggers/Loggers.cpp
+++ b/libs/libloggers/loggers/Loggers.cpp
@@ -1,6 +1,7 @@
 #include "Loggers.h"
 
 #include <iostream>
+#include <Common/SensitiveDataMasker.h>
 #include <Poco/SyslogChannel.h>
 #include <Poco/Util/AbstractConfiguration.h>
 #include "OwnFormattingChannel.h"
@@ -152,12 +153,20 @@ void Loggers::buildLoggers(Poco::Util::AbstractConfiguration & config, Poco::Log
             logger.root().get(level).setLevel(config.getString("logger.levels." + level, "trace"));
 }
 
+void Loggers::setLoggerSensitiveDataMasker(Poco::Logger & logger, DB::SensitiveDataMasker * sensitive_data_masker)
+{
+    if (auto split = dynamic_cast<DB::OwnSplitChannel *>(logger.getChannel())) {
+        split->setMasker(sensitive_data_masker);
+    }
+}
+
 void Loggers::closeLogs(Poco::Logger & logger)
 {
     if (log_file)
         log_file->close();
     if (error_log_file)
         error_log_file->close();
+    // Shouldn't syslog_channel be closed here too?
 
     if (!log_file)
         logger.warning("Logging to console but received signal to close log file (ignoring).");
diff --git a/libs/libloggers/loggers/Loggers.h b/libs/libloggers/loggers/Loggers.h
index 7b3c0860273..848b4eff10b 100644
--- a/libs/libloggers/loggers/Loggers.h
+++ b/libs/libloggers/loggers/Loggers.h
@@ -3,6 +3,8 @@
 #include <Poco/AutoPtr.h>
 #include <Poco/FileChannel.h>
 #include <Poco/Util/Application.h>
+#include <Common/SensitiveDataMasker.h>
+#include "OwnFormattingChannel.h"
 
 namespace Poco::Util
 {
@@ -14,6 +16,8 @@ class Loggers
 {
 public:
     void buildLoggers(Poco::Util::AbstractConfiguration & config, Poco::Logger & logger, const std::string & cmd_name = "");
+    void setLoggerSensitiveDataMasker(Poco::Logger & logger, DB::SensitiveDataMasker * sensitive_data_masker);
+
 
     /// Close log files. On next log write files will be reopened.
     void closeLogs(Poco::Logger & logger);
@@ -27,10 +31,10 @@ protected:
     std::optional<size_t> layer;
 
 private:
-    /// Файлы с логами.
     Poco::AutoPtr<Poco::FileChannel> log_file;
     Poco::AutoPtr<Poco::FileChannel> error_log_file;
     Poco::AutoPtr<Poco::Channel> syslog_channel;
+
     /// Previous value of logger element in config. It is used to reinitialize loggers whenever the value changed.
     std::string config_logger;
 };
diff --git a/libs/libloggers/loggers/OwnPatternFormatter.h b/libs/libloggers/loggers/OwnPatternFormatter.h
index 0e100aa6f33..dc1254cba29 100644
--- a/libs/libloggers/loggers/OwnPatternFormatter.h
+++ b/libs/libloggers/loggers/OwnPatternFormatter.h
@@ -5,18 +5,18 @@
 #include "ExtendedLogChannel.h"
 
 
-/** Форматирует по своему.
-  * Некоторые детали невозможно получить, используя только Poco::PatternFormatter.
+/** Format log messages own way.
+  * We can't obtain some details using Poco::PatternFormatter.
   *
-  * Во-первых, используется номер потока не среди потоков Poco::Thread,
-  *  а среди всех потоков, для которых был получен номер (см. ThreadNumber.h)
+  * Firstly, the thread number here is peaked not from Poco::Thread
+  * threads only, but from all threads with number assigned (see ThreadNumber.h)
   *
-  * Во-вторых, корректно выводится локальная дата и время.
-  * Poco::PatternFormatter плохо работает с локальным временем,
-  *  в ситуациях, когда в ближайшем будущем намечается отмена или введение daylight saving time.
-  *  - см. исходники Poco и http://thread.gmane.org/gmane.comp.time.tz/8883
+  * Secondly, the local date and time are correctly displayed.
+  * Poco::PatternFormatter does not work well with local time,
+  * when timestamps are close to DST timeshift moments.
+  * - see Poco sources and http://thread.gmane.org/gmane.comp.time.tz/8883
   *
-  * Также сделан чуть более эффективным (что имеет мало значения).
+  * Also it's made a bit more efficient (unimportant).
   */
 
 class Loggers;
diff --git a/libs/libloggers/loggers/OwnSplitChannel.cpp b/libs/libloggers/loggers/OwnSplitChannel.cpp
index 0779f6477c3..5069494c507 100644
--- a/libs/libloggers/loggers/OwnSplitChannel.cpp
+++ b/libs/libloggers/loggers/OwnSplitChannel.cpp
@@ -19,6 +19,23 @@ void OwnSplitChannel::log(const Poco::Message & msg)
     if (channels.empty() && (logs_queue == nullptr || msg.getPriority() > logs_queue->max_priority))
         return;
 
+    if (sensitive_data_masker)
+    {
+        auto message_text = msg.getText();
+        auto matches = sensitive_data_masker->wipeSensitiveData(message_text);
+        if (matches > 0)
+        {
+            logSplit({msg, message_text}); // we will continue with the copy of original message with text modified
+            return;
+        }
+
+    }
+    logSplit(msg);
+}
+
+
+void OwnSplitChannel::logSplit(const Poco::Message & msg)
+{
     ExtendedLogMessage msg_ext = ExtendedLogMessage::getFrom(msg);
 
     /// Log data to child channels
@@ -30,6 +47,8 @@ void OwnSplitChannel::log(const Poco::Message & msg)
             channel.first->log(msg); // ordinary child
     }
 
+    auto logs_queue = CurrentThread::getInternalTextLogsQueue();
+
     /// Log to "TCP queue" if message is not too noisy
     if (logs_queue && msg.getPriority() <= logs_queue->max_priority)
     {
@@ -51,6 +70,13 @@ void OwnSplitChannel::log(const Poco::Message & msg)
     /// TODO: Also log to system.internal_text_log table
 }
 
+
+void OwnSplitChannel::setMasker(DB::SensitiveDataMasker * _sensitive_data_masker)
+{
+    std::lock_guard lock(mutex);
+    sensitive_data_masker = _sensitive_data_masker;
+}
+
 void OwnSplitChannel::addChannel(Poco::AutoPtr<Poco::Channel> channel)
 {
     channels.emplace_back(std::move(channel), dynamic_cast<ExtendedLogChannel *>(channel.get()));
diff --git a/libs/libloggers/loggers/OwnSplitChannel.h b/libs/libloggers/loggers/OwnSplitChannel.h
index 3579218f75c..768bdef9dca 100644
--- a/libs/libloggers/loggers/OwnSplitChannel.h
+++ b/libs/libloggers/loggers/OwnSplitChannel.h
@@ -1,8 +1,10 @@
 #pragma once
 #include <vector>
+#include <memory>
 #include <Poco/AutoPtr.h>
 #include <Poco/Channel.h>
 #include "ExtendedLogChannel.h"
+#include <Common/SensitiveDataMasker.h>
 
 
 namespace DB
@@ -16,14 +18,20 @@ public:
     /// Makes an extended message from msg and passes it to the client logs queue and child (if possible)
     void log(const Poco::Message & msg) override;
 
+    void setMasker(DB::SensitiveDataMasker * _sensitive_data_masker);
+
     /// Adds a child channel
     void addChannel(Poco::AutoPtr<Poco::Channel> channel);
 
 private:
+    void logSplit(const Poco::Message & msg);
+
     using ChannelPtr = Poco::AutoPtr<Poco::Channel>;
     /// Handler and its pointer casted to extended interface
     using ExtendedChannelPtrPair = std::pair<ChannelPtr, ExtendedLogChannel *>;
     std::vector<ExtendedChannelPtrPair> channels;
+    DB::SensitiveDataMasker * sensitive_data_masker = nullptr; // global context owns that object, pointer should be reset before context destroying.
+    std::mutex mutex;
 };
 
 }