diff --git a/core/account.cpp b/core/account.cpp
index 08321d3..48c48f9 100644
--- a/core/account.cpp
+++ b/core/account.cpp
@@ -634,16 +634,16 @@ void Core::Account::onDiscoveryInfoReceived(const QXmppDiscoveryIq& info)
         QString node = info.queryNode();
         if (!node.isEmpty()) {
             QStringList feats = info.features();
-            std::list<Shared::Identity> identities;
+            std::set<Shared::Identity> identities;
             std::set<QString> features(feats.begin(), feats.end());
             QList<QXmppDiscoveryIq::Identity> idents = info.identities();
             for (const QXmppDiscoveryIq::Identity& ident : idents) {
-                identities.emplace_back();
-                Shared::Identity& identity = identities.back();
+                Shared::Identity identity;
                 identity.category = ident.category();
                 identity.language = ident.language();
                 identity.name = ident.name();
                 identity.type = ident.type();
+                identities.insert(identity);
 
                 qDebug() << "    " << identity.name << identity.category << identity.type;
             }
@@ -655,6 +655,16 @@ void Core::Account::onDiscoveryInfoReceived(const QXmppDiscoveryIq& info)
     }
 }
 
+void Core::Account::discoverInfo(const QString& address, const QString& node) {
+    if (state == Shared::ConnectionState::connected) {
+        dm->requestInfo(address, node);
+    } else {
+        qDebug() << "An attempt to send a discover info by account" << name <<
+                    "sending request to" << address << "about node" << node <<
+                    "but the account is not in the connected state, skipping";
+    }
+}
+
 void Core::Account::handleDisconnection()
 {
     cm->setCarbonsEnabled(false);
diff --git a/core/account.h b/core/account.h
index 5651ad9..a409490 100644
--- a/core/account.h
+++ b/core/account.h
@@ -155,7 +155,7 @@ signals:
     void uploadFile(const QFileInfo& file, const QUrl& set, const QUrl& get, QMap<QString, QString> headers);
     void uploadFileError(const QString& jid, const QString& messageId, const QString& error);
     void needPassword();
-    void infoDiscovered(const QString& address, const QString& node, const std::list<Shared::Identity>& identities, const std::set<QString>& features);
+    void infoDiscovered(const QString& address, const QString& node, const std::set<Shared::Identity>& identities, const std::set<QString>& features);
     
 private:
     QString name;
diff --git a/core/components/clientcache.cpp b/core/components/clientcache.cpp
index 0259f9c..a054428 100644
--- a/core/components/clientcache.cpp
+++ b/core/components/clientcache.cpp
@@ -14,12 +14,14 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-
 #include "clientcache.h"
 
+#include <QDebug>
+
 Core::ClientCache::ClientCache():
     requested(),
-    cache("clients")
+    cache("clients"),
+    specific()
 {
     cache.open();
 }
@@ -39,9 +41,9 @@ bool Core::ClientCache::checkClient(const QString& node, const QString& ver, con
     QString id = node + "/" + ver;
     if (requested.count(id) == 0 && !cache.checkRecord(id)) {
         Shared::ClientInfo& info = requested.insert(std::make_pair(id, Shared::ClientInfo())).first->second;
-        info.capabilitiesNode = node;
-        info.capabilitiesVerification = ver;
-        info.capabilitiesHash = hash;
+        info.node = node;
+        info.verification = ver;
+        info.hash = hash;
         emit requestClientInfo(id);
         return false;
     }
@@ -49,7 +51,28 @@ bool Core::ClientCache::checkClient(const QString& node, const QString& ver, con
     return true;
 }
 
+bool Core::ClientCache::registerClientInfo (
+    const QString& sourceFullJid,
+    const QString& id,
+    const std::set<Shared::Identity>& identities,
+    const std::set<QString>& features)
+{
+    std::map<QString, Shared::ClientInfo>::iterator itr = requested.find(id);
+    if (itr != requested.end()) {
+        Shared::ClientInfo& info = itr->second;
+        info.identities = identities;
+        info.extensions = features;
 
-bool Core::ClientCache::registerClientInfo(const QString& sourceFullJid, const QString& id, const Shared::Identity& identity, const std::set<QString>& features) {
-
+        bool valid = info.valid();
+        if (valid) {
+            cache.addRecord(id, info);
+        } else {
+            info.specificPresence = sourceFullJid;
+            specific.insert(std::make_pair(sourceFullJid, info));
+        }
+        requested.erase(id);
+        return valid;
+    } else {
+        return false;
+    }
 }
diff --git a/core/components/clientcache.h b/core/components/clientcache.h
index 78c7e84..b2ff70d 100644
--- a/core/components/clientcache.h
+++ b/core/components/clientcache.h
@@ -43,11 +43,12 @@ signals:
 
 public slots:
     bool checkClient(const QString& node, const QString& ver, const QString& hash);
-    bool registerClientInfo(const QString& sourceFullJid, const QString& id, const Shared::Identity& identity, const std::set<QString>& features);
+    bool registerClientInfo(const QString& sourceFullJid, const QString& id, const std::set<Shared::Identity>& identities, const std::set<QString>& features);
 
 private:
     std::map<QString, Shared::ClientInfo> requested;
     Cache<Shared::ClientInfo> cache;
+    std::map<QString, Shared::ClientInfo> specific;
 };
 
 }
diff --git a/core/squawk.cpp b/core/squawk.cpp
index 5edcf58..3b976b0 100644
--- a/core/squawk.cpp
+++ b/core/squawk.cpp
@@ -320,25 +320,27 @@ void Core::Squawk::onAccountAddPresence(const QString& jid, const QString& name,
     Account* acc = static_cast<Account*>(sender());
     emit addPresence(acc->getName(), jid, name, data);
 
-    QString node = data["capabilityNode"].toString();
-    QString ver = data["capabilityVer"].toString();
-    QString hash = data["capabilityHash"].toString();
-    if (!clientCache.checkClient(node, ver, hash)) {
-        acc->discoverInfo(jid + "/" + name, node + "/" + ver);
+    //it's equal if a MUC sends its status with presence of the same jid (ex: muc@srv.im/muc@srv.im), it's not a client, so, no need to request
+    if (jid != name) {
+        QString node = data["capabilityNode"].toString();
+        QString ver = data["capabilityVer"].toString();
+        QString hash = data["capabilityHash"].toString();
+        if (!clientCache.checkClient(node, ver, hash)) {
+            acc->discoverInfo(jid + "/" + name, node + "/" + ver);
+        }
     }
 }
 
 void Core::Squawk::onAccountInfoDiscovered(
     const QString& address,
     const QString& node,
-    const std::list<Shared::Identity>& identities,
+    const std::set<Shared::Identity>& identities,
     const std::set<QString>& features)
 {
     Account* acc = static_cast<Account*>(sender());
 
-    if (identities.size() != 1 || clientCache.registerClientInfo(address, node, identities.back(), features)) {
+    if (!clientCache.registerClientInfo(address, node, identities, features)) {
         qDebug() << "Account" << acc->getName() << "received an ill-formed client discovery response from" << address << "about" << node;
-        return;
     }
 }
 
diff --git a/core/squawk.h b/core/squawk.h
index ea17cdf..cdaaf6e 100644
--- a/core/squawk.h
+++ b/core/squawk.h
@@ -183,7 +183,7 @@ private slots:
     void onWalletOpened(bool success);
     void onWalletRejectPassword(const QString& login);
 
-    void onAccountInfoDiscovered(const QString& address, const QString& node, const std::list<Shared::Identity>& identities, const std::set<QString>& features);
+    void onAccountInfoDiscovered(const QString& address, const QString& node, const std::set<Shared::Identity>& identities, const std::set<QString>& features);
     
 private:
     void readSettings();
diff --git a/shared/CMakeLists.txt b/shared/CMakeLists.txt
index 5828bd4..7495d4e 100644
--- a/shared/CMakeLists.txt
+++ b/shared/CMakeLists.txt
@@ -21,4 +21,5 @@ target_sources(squawk PRIVATE
   clientinfo.h
   clientinfo.cpp
   identity.h
+  identity.cpp
   )
diff --git a/shared/clientinfo.cpp b/shared/clientinfo.cpp
index 3a2f441..86af1c8 100644
--- a/shared/clientinfo.cpp
+++ b/shared/clientinfo.cpp
@@ -16,30 +16,42 @@
 
 #include "clientinfo.h"
 
+const std::map<QString, QCryptographicHash::Algorithm> Shared::ClientInfo::hashes = {
+    //md2 is missing
+    {"md5", QCryptographicHash::Md5},
+    {"sha-1", QCryptographicHash::Sha1},
+    {"sha-224", QCryptographicHash::Sha224},
+    {"sha-256", QCryptographicHash::Sha256},
+    {"sha-384", QCryptographicHash::Sha384},
+    {"sha-512", QCryptographicHash::Sha512},
+    //shake128 is missing
+    //shake256 is missing
+
+};
+
 Shared::ClientInfo::ClientInfo():
-    name(),
-    category(),
-    type(),
-    capabilitiesNode(),
-    capabilitiesVerification(),
-    capabilitiesHash(),
-    specificPresence(),
-    capabilitiesExtensions() {}
+    identities(),
+    extensions(),
+    node(),
+    verification(),
+    hash(),
+    specificPresence() {}
 
 QString Shared::ClientInfo::getId() const {
-    return capabilitiesNode + "/" + capabilitiesVerification;
+    return node + "/" + verification;
 }
 
 
 QDataStream & Shared::ClientInfo::operator >> (QDataStream& stream) const {
-    stream << name;
-    stream << category;
-    stream << type;
-    stream << capabilitiesNode;
-    stream << capabilitiesVerification;
-    stream << capabilitiesHash;
-    stream << (quint8)capabilitiesExtensions.size();
-    for (const QString& ext : capabilitiesExtensions) {
+    stream << node;
+    stream << verification;
+    stream << hash;
+    stream << (quint8)identities.size();
+    for (const Shared::Identity& identity : identities) {
+        stream << identity;
+    }
+    stream << (quint8)extensions.size();
+    for (const QString& ext : extensions) {
         stream << ext;
     }
 
@@ -47,29 +59,53 @@ QDataStream & Shared::ClientInfo::operator >> (QDataStream& stream) const {
 }
 
 QDataStream & Shared::ClientInfo::operator << (QDataStream& stream) {
-    stream >> name;
-    stream >> category;
-    stream >> type;
-    stream >> capabilitiesNode;
-    stream >> capabilitiesVerification;
-    stream >> capabilitiesHash;
+    stream >> node;
+    stream >> verification;
+    stream >> hash;
 
     quint8 size;
+    stream >> size;
+    for (quint8 i = 0; i < size; ++i) {
+        Shared::Identity identity;
+        stream >> identity;
+        identities.insert(identity);
+    }
+
     stream >> size;
     for (quint8 i = 0; i < size; ++i) {
         QString ext;
         stream >> ext;
-        capabilitiesExtensions.insert(ext);
+        extensions.insert(ext);
     }
 
     return stream;
 }
 
-QDataStream& operator<< (QDataStream& stream, const Shared::ClientInfo& image) {
-    image >> stream;
+bool Shared::ClientInfo::valid() const {
+    std::map<QString, QCryptographicHash::Algorithm>::const_iterator itr = hashes.find(hash);
+    if (itr == hashes.end()) {
+        return false;
+    }
+
+    QCryptographicHash calc(itr->second);
+    QString validationString = "";
+    for (const Identity& identity : identities) {
+        calc.addData((identity.category + "/" + identity.type + "/" + identity.language + "/" + identity.name + "<").toUtf8());
+    }
+    for (const QString& ext : extensions) {
+        calc.addData((ext + "<").toUtf8());
+    }
+
+    QString result = calc.result().toBase64();
+
+    return result == verification;
+}
+
+QDataStream& operator << (QDataStream& stream, const Shared::ClientInfo& info) {
+    info >> stream;
     return stream;
 }
-QDataStream& operator>> (QDataStream& stream, Shared::ClientInfo& image) {
-    image << stream;
+QDataStream& operator >> (QDataStream& stream, Shared::ClientInfo& info) {
+    info << stream;
     return stream;
 }
diff --git a/shared/clientinfo.h b/shared/clientinfo.h
index 55dd29f..53c7dd0 100644
--- a/shared/clientinfo.h
+++ b/shared/clientinfo.h
@@ -21,6 +21,9 @@
 
 #include <QDataStream>
 #include <QString>
+#include <QCryptographicHash>
+
+#include <shared/identity.h>
 
 namespace Shared {
 
@@ -30,24 +33,26 @@ public:
     ClientInfo();
 
     QString getId() const;
+    bool valid() const;
 
     QDataStream& operator << (QDataStream& stream);
     QDataStream& operator >> (QDataStream& stream) const;
 
 public:
-    QString name;
-    QString category;
-    QString type;
-    QString capabilitiesNode;
-    QString capabilitiesVerification;
-    QString capabilitiesHash;
+    std::set<Identity> identities;
+    std::set<QString> extensions;
+    QString node;
+    QString verification;
+    QString hash;
     QString specificPresence;
-    std::set<QString> capabilitiesExtensions;
+
+private:
+    static const std::map<QString, QCryptographicHash::Algorithm> hashes;
 };
 
 }
 
-QDataStream& operator<< (QDataStream& stream, const Shared::ClientInfo& image);
-QDataStream& operator>> (QDataStream& stream, Shared::ClientInfo& image);
+QDataStream& operator << (QDataStream& stream, const Shared::ClientInfo& info);
+QDataStream& operator >> (QDataStream& stream, Shared::ClientInfo& info);
 
 #endif // SHARED_CLIENTINFO_H
diff --git a/shared/identity.cpp b/shared/identity.cpp
new file mode 100644
index 0000000..a0a4f0a
--- /dev/null
+++ b/shared/identity.cpp
@@ -0,0 +1,142 @@
+/*
+ * Squawk messenger.
+ * Copyright (C) 2019  Yury Gubich <blue@macaw.me>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "identity.h"
+
+Shared::Identity::Identity():
+    category(),
+    type(),
+    language(),
+    name() {}
+
+bool Shared::Identity::operator==(const Shared::Identity& other) const {
+    return category == other.category && type == other.type && language == other.language && name == other.name;
+}
+
+bool Shared::Identity::operator!=(const Shared::Identity& other) const {
+    return category != other.category || type != other.type || language != other.language || name != other.name;
+}
+
+bool Shared::Identity::operator > (const Shared::Identity& other) const {
+    if (category > other.category) {
+        return true;
+    } else if (category < other.category) {
+        return false;
+    } else if (type > other.type) {
+        return true;
+    } else if (type < other.type) {
+        return false;
+    } else if (language > other.language) {
+        return true;
+    } else if (language < other.language) {
+        return false;
+    } else if (name > other.name) {
+        return true;
+    } else {
+        return false;
+    }
+}
+
+bool Shared::Identity::operator < (const Shared::Identity& other) const {
+    if (category < other.category) {
+        return true;
+    } else if (category > other.category) {
+        return false;
+    } else if (type < other.type) {
+        return true;
+    } else if (type > other.type) {
+        return false;
+    } else if (language < other.language) {
+        return true;
+    } else if (language > other.language) {
+        return false;
+    } else if (name < other.name) {
+        return true;
+    } else {
+        return false;
+    }
+}
+
+bool Shared::Identity::operator >= (const Shared::Identity& other) const {
+    if (category > other.category) {
+        return true;
+    } else if (category < other.category) {
+        return false;
+    } else if (type > other.type) {
+        return true;
+    } else if (type < other.type) {
+        return false;
+    } else if (language > other.language) {
+        return true;
+    } else if (language < other.language) {
+        return false;
+    } else if (name > other.name) {
+        return true;
+    } else if (name < other.name) {
+        return false;
+    } else {
+        return true;
+    }
+}
+
+bool Shared::Identity::operator <= (const Shared::Identity& other) const {
+    if (category < other.category) {
+        return true;
+    } else if (category > other.category) {
+        return false;
+    } else if (type < other.type) {
+        return true;
+    } else if (type > other.type) {
+        return false;
+    } else if (language < other.language) {
+        return true;
+    } else if (language > other.language) {
+        return false;
+    } else if (name < other.name) {
+        return true;
+    } else if (name > other.name) {
+        return false;
+    } else {
+        return true;
+    }
+}
+
+QDataStream & Shared::Identity::operator >> (QDataStream& stream) const {
+    stream << category;
+    stream << type;
+    stream << language;
+    stream << name;
+}
+
+QDataStream & Shared::Identity::operator << (QDataStream& stream) {
+    stream >> category;
+    stream >> type;
+    stream >> language;
+    stream >> name;
+}
+
+QDataStream & operator >> (QDataStream& stream, Shared::Identity& identity) {
+    identity << stream;
+    return stream;
+}
+
+QDataStream & operator << (QDataStream& stream, const Shared::Identity& identity) {
+    identity >> stream;
+    return stream;
+}
+
diff --git a/shared/identity.h b/shared/identity.h
index 6041e1a..c19102b 100644
--- a/shared/identity.h
+++ b/shared/identity.h
@@ -19,17 +19,34 @@
 #ifndef SHARED_IDENTITY_H
 #define SHARED_IDENTITY_H
 
+#include <QDataStream>
 #include <QString>
 
 namespace Shared {
 
-struct Identity {
+class Identity {
+public:
+    Identity();
+
+    QDataStream& operator << (QDataStream& stream);
+    QDataStream& operator >> (QDataStream& stream) const;
+
+    bool operator < (const Identity& other) const;
+    bool operator > (const Identity& other) const;
+    bool operator >= (const Identity& other) const;
+    bool operator <= (const Identity& other) const;
+    bool operator == (const Identity& other) const;
+    bool operator != (const Identity& other) const;
+public:
     QString category;
+    QString type;
     QString language;
     QString name;
-    QString type;
 };
 
 }
 
+QDataStream& operator << (QDataStream& stream, const Shared::Identity& identity);
+QDataStream& operator >> (QDataStream& stream, Shared::Identity& identity);
+
 #endif //SHARED_IDENTITY_H