diff --git a/native/cpp/CommonCpp/CryptoTools/CryptoModule.cpp b/native/cpp/CommonCpp/CryptoTools/CryptoModule.cpp
index 5859f9a20..59d8e197f 100644
--- a/native/cpp/CommonCpp/CryptoTools/CryptoModule.cpp
+++ b/native/cpp/CommonCpp/CryptoTools/CryptoModule.cpp
@@ -1,503 +1,463 @@
 #include "CryptoModule.h"
 #include "Logger.h"
 #include "PlatformSpecificTools.h"
 #include "olm/account.hh"
 #include "olm/session.hh"
 
 #include <folly/dynamic.h>
 #include <folly/json.h>
 #include <ctime>
 #include <stdexcept>
 
 namespace comm {
 namespace crypto {
 
 CryptoModule::CryptoModule(std::string id) : id{id} {
   this->createAccount();
 }
 
 CryptoModule::CryptoModule(
     std::string id,
     std::string secretKey,
     Persist persist)
     : id{id} {
   if (persist.isEmpty()) {
     this->createAccount();
   } else {
     this->restoreFromB64(secretKey, persist);
   }
 }
 
 OlmAccount *CryptoModule::getOlmAccount() {
   return reinterpret_cast<OlmAccount *>(this->accountBuffer.data());
 }
 
 void CryptoModule::createAccount() {
   this->accountBuffer.resize(::olm_account_size());
   ::olm_account(this->accountBuffer.data());
 
   size_t randomSize = ::olm_create_account_random_length(this->getOlmAccount());
   OlmBuffer randomBuffer;
   PlatformSpecificTools::generateSecureRandomBytes(randomBuffer, randomSize);
 
   if (-1 ==
       ::olm_create_account(
           this->getOlmAccount(), randomBuffer.data(), randomSize)) {
     throw std::runtime_error{
         "error createAccount => " +
         std::string{::olm_account_last_error(this->getOlmAccount())}};
   };
 }
 
 void CryptoModule::exposePublicIdentityKeys() {
   size_t identityKeysSize =
       ::olm_account_identity_keys_length(this->getOlmAccount());
   if (this->keys.identityKeys.size() == identityKeysSize) {
     return;
   }
   this->keys.identityKeys.resize(
       ::olm_account_identity_keys_length(this->getOlmAccount()));
   if (-1 ==
       ::olm_account_identity_keys(
           this->getOlmAccount(),
           this->keys.identityKeys.data(),
           this->keys.identityKeys.size())) {
     throw std::runtime_error{
         "error generateIdentityKeys => " +
         std::string{::olm_account_last_error(this->getOlmAccount())}};
   }
 }
 
 void CryptoModule::generateOneTimeKeys(size_t oneTimeKeysAmount) {
   size_t numRandomBytesRequired =
       ::olm_account_generate_one_time_keys_random_length(
           this->getOlmAccount(), oneTimeKeysAmount);
   OlmBuffer random;
   PlatformSpecificTools::generateSecureRandomBytes(
       random, numRandomBytesRequired);
 
   if (-1 ==
       ::olm_account_generate_one_time_keys(
           this->getOlmAccount(),
           oneTimeKeysAmount,
           random.data(),
           random.size())) {
     throw std::runtime_error{
         "error generateOneTimeKeys => " +
         std::string{::olm_account_last_error(this->getOlmAccount())}};
   }
 }
 
 // returns number of published keys
 size_t CryptoModule::publishOneTimeKeys() {
   this->keys.oneTimeKeys.resize(
       ::olm_account_one_time_keys_length(this->getOlmAccount()));
   if (-1 ==
       ::olm_account_one_time_keys(
           this->getOlmAccount(),
           this->keys.oneTimeKeys.data(),
           this->keys.oneTimeKeys.size())) {
     throw std::runtime_error{
         "error publishOneTimeKeys => " +
         std::string{::olm_account_last_error(this->getOlmAccount())}};
   }
   return ::olm_account_mark_keys_as_published(this->getOlmAccount());
 }
 
 bool CryptoModule::prekeyExistsAndOlderThan(uint64_t threshold) {
   // Our fork of Olm only remembers two prekeys at a time.
   // If the new one hasn't been published, then the old one is still active.
   // In that scenario, we need to avoid rotating the prekey because it will
   // result in the old active prekey being discarded.
   if (this->getUnpublishedPrekey().has_value()) {
     return false;
   }
 
   uint64_t currentTime = std::time(nullptr);
   uint64_t lastPrekeyPublishTime =
       ::olm_account_get_last_prekey_publish_time(this->getOlmAccount());
 
   return currentTime - lastPrekeyPublishTime >= threshold;
 }
 
 Keys CryptoModule::keysFromStrings(
     const std::string &identityKeys,
     const std::string &oneTimeKeys) {
   return {
       OlmBuffer(identityKeys.begin(), identityKeys.end()),
       OlmBuffer(oneTimeKeys.begin(), oneTimeKeys.end())};
 }
 
 std::string CryptoModule::getIdentityKeys() {
   this->exposePublicIdentityKeys();
   return std::string{
       this->keys.identityKeys.begin(), this->keys.identityKeys.end()};
 }
 
 std::string
 CryptoModule::getOneTimeKeysForPublishing(size_t oneTimeKeysAmount) {
   OlmBuffer unpublishedOneTimeKeys;
   unpublishedOneTimeKeys.resize(
       ::olm_account_one_time_keys_length(this->getOlmAccount()));
   if (-1 ==
       ::olm_account_one_time_keys(
           this->getOlmAccount(),
           unpublishedOneTimeKeys.data(),
           unpublishedOneTimeKeys.size())) {
     throw std::runtime_error{
         "error getOneTimeKeysForPublishing => " +
         std::string{::olm_account_last_error(this->getOlmAccount())}};
   }
   std::string unpublishedKeysString =
       std::string{unpublishedOneTimeKeys.begin(), unpublishedOneTimeKeys.end()};
 
   folly::dynamic parsedUnpublishedKeys =
       folly::parseJson(unpublishedKeysString);
 
   size_t numUnpublishedKeys = parsedUnpublishedKeys["curve25519"].size();
 
   if (numUnpublishedKeys < oneTimeKeysAmount) {
     this->generateOneTimeKeys(oneTimeKeysAmount - numUnpublishedKeys);
   }
 
   this->publishOneTimeKeys();
 
   return std::string{
       this->keys.oneTimeKeys.begin(), this->keys.oneTimeKeys.end()};
 }
 
 std::uint8_t CryptoModule::getNumPrekeys() {
   return reinterpret_cast<olm::Account *>(this->getOlmAccount())->num_prekeys;
 }
 
 std::string CryptoModule::getPrekey() {
   OlmBuffer prekey;
   prekey.resize(::olm_account_prekey_length(this->getOlmAccount()));
 
   if (-1 ==
       ::olm_account_prekey(
           this->getOlmAccount(), prekey.data(), prekey.size())) {
     throw std::runtime_error{
         "error getPrekey => " +
         std::string{::olm_account_last_error(this->getOlmAccount())}};
   }
 
   return std::string{std::string{prekey.begin(), prekey.end()}};
 }
 
 std::string CryptoModule::getPrekeySignature() {
   size_t signatureSize = ::olm_account_signature_length(this->getOlmAccount());
 
   OlmBuffer signatureBuffer;
   signatureBuffer.resize(signatureSize);
 
   if (-1 ==
       ::olm_account_prekey_signature(
           this->getOlmAccount(), signatureBuffer.data())) {
     throw std::runtime_error{
         "error getPrekeySignature => " +
         std::string{::olm_account_last_error(this->getOlmAccount())}};
   }
 
   return std::string{signatureBuffer.begin(), signatureBuffer.end()};
 }
 
 std::optional<std::string> CryptoModule::getUnpublishedPrekey() {
   OlmBuffer prekey;
   prekey.resize(::olm_account_prekey_length(this->getOlmAccount()));
 
   std::size_t retval = ::olm_account_unpublished_prekey(
       this->getOlmAccount(), prekey.data(), prekey.size());
 
   if (0 == retval) {
     return std::nullopt;
   } else if (-1 == retval) {
     throw std::runtime_error{
         "error getUnpublishedPrekey => " +
         std::string{::olm_account_last_error(this->getOlmAccount())}};
   }
 
   return std::string{prekey.begin(), prekey.end()};
 }
 
 std::string CryptoModule::generateAndGetPrekey() {
   size_t prekeySize =
       ::olm_account_generate_prekey_random_length(this->getOlmAccount());
 
   OlmBuffer random;
   PlatformSpecificTools::generateSecureRandomBytes(random, prekeySize);
 
   if (-1 ==
       ::olm_account_generate_prekey(
           this->getOlmAccount(), random.data(), random.size())) {
     throw std::runtime_error{
         "error generateAndGetPrekey => " +
         std::string{::olm_account_last_error(this->getOlmAccount())}};
   }
 
   OlmBuffer prekey;
   prekey.resize(::olm_account_prekey_length(this->getOlmAccount()));
 
   if (-1 ==
       ::olm_account_prekey(
           this->getOlmAccount(), prekey.data(), prekey.size())) {
     throw std::runtime_error{
         "error generateAndGetPrekey => " +
         std::string{::olm_account_last_error(this->getOlmAccount())}};
   }
 
   return std::string{prekey.begin(), prekey.end()};
 }
 
 void CryptoModule::markPrekeyAsPublished() {
   ::olm_account_mark_prekey_as_published(this->getOlmAccount());
 }
 
 void CryptoModule::forgetOldPrekey() {
   ::olm_account_forget_old_prekey(this->getOlmAccount());
 }
 
 void CryptoModule::initializeInboundForReceivingSession(
     const std::string &targetDeviceId,
     const OlmBuffer &encryptedMessage,
     const OlmBuffer &idKeys,
     const bool overwrite) {
   if (this->hasSessionFor(targetDeviceId)) {
     if (overwrite) {
       this->sessions.erase(this->sessions.find(targetDeviceId));
     } else {
       throw std::runtime_error{
           "error initializeInboundForReceivingSession => session already "
           "initialized"};
     }
   }
   std::unique_ptr<Session> newSession = Session::createSessionAsResponder(
       this->getOlmAccount(),
       this->keys.identityKeys.data(),
       encryptedMessage,
       idKeys);
   this->sessions.insert(make_pair(targetDeviceId, std::move(newSession)));
 }
 
 void CryptoModule::initializeOutboundForSendingSession(
     const std::string &targetDeviceId,
     const OlmBuffer &idKeys,
     const OlmBuffer &preKeys,
     const OlmBuffer &preKeySignature,
     const OlmBuffer &oneTimeKey) {
   if (this->hasSessionFor(targetDeviceId)) {
     Logger::log(
         "olm session overwritten for the device with id: " + targetDeviceId);
     this->sessions.erase(this->sessions.find(targetDeviceId));
   }
   std::unique_ptr<Session> newSession = Session::createSessionAsInitializer(
       this->getOlmAccount(),
       this->keys.identityKeys.data(),
       idKeys,
       preKeys,
       preKeySignature,
       oneTimeKey);
   this->sessions.insert(make_pair(targetDeviceId, std::move(newSession)));
 }
 
 bool CryptoModule::hasSessionFor(const std::string &targetDeviceId) {
   return (this->sessions.find(targetDeviceId) != this->sessions.end());
 }
 
 std::shared_ptr<Session>
 CryptoModule::getSessionByDeviceId(const std::string &deviceId) {
   return this->sessions.at(deviceId);
 }
 
+void CryptoModule::removeSessionByDeviceId(const std::string &deviceId) {
+  this->sessions.erase(deviceId);
+}
+
 Persist CryptoModule::storeAsB64(const std::string &secretKey) {
   Persist persist;
   size_t accountPickleLength =
       ::olm_pickle_account_length(this->getOlmAccount());
   OlmBuffer accountPickleBuffer(accountPickleLength);
   if (accountPickleLength !=
       ::olm_pickle_account(
           this->getOlmAccount(),
           secretKey.data(),
           secretKey.size(),
           accountPickleBuffer.data(),
           accountPickleLength)) {
     throw std::runtime_error{
         "error storeAsB64 => " +
         std::string{::olm_account_last_error(this->getOlmAccount())}};
   }
   persist.account = accountPickleBuffer;
 
   std::unordered_map<std::string, std::shared_ptr<Session>>::iterator it;
   for (it = this->sessions.begin(); it != this->sessions.end(); ++it) {
     OlmBuffer buffer = it->second->storeAsB64(secretKey);
     persist.sessions.insert(make_pair(it->first, buffer));
   }
 
   return persist;
 }
 
 void CryptoModule::restoreFromB64(
     const std::string &secretKey,
     Persist persist) {
   this->accountBuffer.resize(::olm_account_size());
   ::olm_account(this->accountBuffer.data());
   if (-1 ==
       ::olm_unpickle_account(
           this->getOlmAccount(),
           secretKey.data(),
           secretKey.size(),
           persist.account.data(),
           persist.account.size())) {
     throw std::runtime_error{
         "error restoreFromB64 => " +
         std::string{::olm_account_last_error(this->getOlmAccount())}};
   }
 
   std::unordered_map<std::string, OlmBuffer>::iterator it;
   for (it = persist.sessions.begin(); it != persist.sessions.end(); ++it) {
-    std::unique_ptr<Session> session = session->restoreFromB64(
-        this->getOlmAccount(),
-        this->keys.identityKeys.data(),
-        secretKey,
-        it->second);
+    std::unique_ptr<Session> session =
+        session->restoreFromB64(secretKey, it->second);
     this->sessions.insert(make_pair(it->first, move(session)));
   }
 }
 
 EncryptedData CryptoModule::encrypt(
     const std::string &targetDeviceId,
     const std::string &content) {
   if (!this->hasSessionFor(targetDeviceId)) {
     throw std::runtime_error{"error encrypt => uninitialized session"};
   }
   OlmSession *session = this->sessions.at(targetDeviceId)->getOlmSession();
   OlmBuffer encryptedMessage(
       ::olm_encrypt_message_length(session, content.size()));
   OlmBuffer messageRandom;
   PlatformSpecificTools::generateSecureRandomBytes(
       messageRandom, ::olm_encrypt_random_length(session));
   size_t messageType = ::olm_encrypt_message_type(session);
   if (-1 ==
       ::olm_encrypt(
           session,
           (uint8_t *)content.data(),
           content.size(),
           messageRandom.data(),
           messageRandom.size(),
           encryptedMessage.data(),
           encryptedMessage.size())) {
     throw std::runtime_error{
         "error encrypt => " + std::string{::olm_session_last_error(session)}};
   }
   return {encryptedMessage, messageType};
 }
 
 std::string CryptoModule::decrypt(
     const std::string &targetDeviceId,
     EncryptedData &encryptedData) {
   if (!this->hasSessionFor(targetDeviceId)) {
     throw std::runtime_error{"error decrypt => uninitialized session"};
   }
-  OlmSession *session = this->sessions.at(targetDeviceId)->getOlmSession();
-
-  OlmBuffer utilityBuffer(::olm_utility_size());
-  OlmUtility *olmUtility = ::olm_utility(utilityBuffer.data());
-
-  OlmBuffer messageHashBuffer(::olm_sha256_length(olmUtility));
-  ::olm_sha256(
-      olmUtility,
-      encryptedData.message.data(),
-      encryptedData.message.size(),
-      messageHashBuffer.data(),
-      messageHashBuffer.size());
-
-  OlmBuffer tmpEncryptedMessage(encryptedData.message);
-  size_t maxSize = ::olm_decrypt_max_plaintext_length(
-      session,
-      encryptedData.messageType,
-      tmpEncryptedMessage.data(),
-      tmpEncryptedMessage.size());
-
-  if (maxSize == -1) {
-    throw std::runtime_error{
-        "error decrypt_max_plaintext_length => " +
-        std::string{::olm_session_last_error(session)} + ". Hash: " +
-        std::string{messageHashBuffer.begin(), messageHashBuffer.end()}};
-  }
-
-  OlmBuffer decryptedMessage(maxSize);
-  size_t decryptedSize = ::olm_decrypt(
-      session,
-      encryptedData.messageType,
-      encryptedData.message.data(),
-      encryptedData.message.size(),
-      decryptedMessage.data(),
-      decryptedMessage.size());
-  if (decryptedSize == -1) {
-    throw std::runtime_error{
-        "error decrypt => " + std::string{::olm_session_last_error(session)} +
-        ". Hash: " +
-        std::string{messageHashBuffer.begin(), messageHashBuffer.end()}};
-  }
-  return std::string{(char *)decryptedMessage.data(), decryptedSize};
+  return this->sessions.at(targetDeviceId)->decrypt(encryptedData);
 }
 
 std::string CryptoModule::signMessage(const std::string &message) {
   OlmBuffer signature;
   signature.resize(::olm_account_signature_length(this->getOlmAccount()));
   size_t signatureLength = ::olm_account_sign(
       this->getOlmAccount(),
       (uint8_t *)message.data(),
       message.length(),
       signature.data(),
       signature.size());
   if (signatureLength == -1) {
     throw std::runtime_error{
         "olm error: " +
         std::string{::olm_account_last_error(this->getOlmAccount())}};
   }
   return std::string{(char *)signature.data(), signatureLength};
 }
 
 void CryptoModule::verifySignature(
     const std::string &publicKey,
     const std::string &message,
     const std::string &signature) {
   OlmBuffer utilityBuffer;
   utilityBuffer.resize(::olm_utility_size());
   OlmUtility *olmUtility = ::olm_utility(utilityBuffer.data());
   ssize_t verificationResult = ::olm_ed25519_verify(
       olmUtility,
       (uint8_t *)publicKey.data(),
       publicKey.length(),
       (uint8_t *)message.data(),
       message.length(),
       (uint8_t *)signature.data(),
       signature.length());
   if (verificationResult == -1) {
     throw std::runtime_error{
         "olm error: " + std::string{::olm_utility_last_error(olmUtility)}};
   }
 }
 
 std::optional<std::string> CryptoModule::validatePrekey() {
   static const uint64_t maxPrekeyPublishTime = 10 * 60;
   static const uint64_t maxOldPrekeyAge = 2 * 60;
   std::optional<std::string> maybeNewPrekey;
 
   bool shouldRotatePrekey =
       this->prekeyExistsAndOlderThan(maxPrekeyPublishTime);
   if (shouldRotatePrekey) {
     maybeNewPrekey = this->generateAndGetPrekey();
   }
 
   bool shouldForgetPrekey = this->prekeyExistsAndOlderThan(maxOldPrekeyAge);
   if (shouldForgetPrekey) {
     this->forgetOldPrekey();
   }
 
   return maybeNewPrekey;
 }
 
 } // namespace crypto
 } // namespace comm
diff --git a/native/cpp/CommonCpp/CryptoTools/CryptoModule.h b/native/cpp/CommonCpp/CryptoTools/CryptoModule.h
index eafc55c45..4e4b44089 100644
--- a/native/cpp/CommonCpp/CryptoTools/CryptoModule.h
+++ b/native/cpp/CommonCpp/CryptoTools/CryptoModule.h
@@ -1,88 +1,89 @@
 #pragma once
 
 #include <memory>
 #include <string>
 #include <unordered_map>
 
 #include "olm/olm.h"
 
 #include "Persist.h"
 #include "Session.h"
 #include "Tools.h"
 
 namespace comm {
 namespace crypto {
 
 class CryptoModule {
 
   OlmBuffer accountBuffer;
 
   std::unordered_map<std::string, std::shared_ptr<Session>> sessions = {};
 
   Keys keys;
 
   OlmAccount *getOlmAccount();
   void createAccount();
   void exposePublicIdentityKeys();
   void generateOneTimeKeys(size_t oneTimeKeysAmount);
   std::string generateAndGetPrekey();
   // returns number of published keys
   size_t publishOneTimeKeys();
   bool prekeyExistsAndOlderThan(uint64_t threshold);
 
 public:
   const std::string id;
   CryptoModule(std::string id);
   CryptoModule(std::string id, std::string secretKey, Persist persist);
 
   // CryptoModule's accountBuffer cannot be safely copied
   // See explanation in https://phab.comm.dev/D9562
   CryptoModule(const CryptoModule &) = delete;
 
   static Keys keysFromStrings(
       const std::string &identityKeys,
       const std::string &oneTimeKeys);
 
   std::string getIdentityKeys();
   std::string getOneTimeKeysForPublishing(size_t oneTimeKeysAmount = 10);
 
   // Prekey rotation methods for X3DH
   std::uint8_t getNumPrekeys();
   std::string getPrekey();
   std::string getPrekeySignature();
   std::optional<std::string> getUnpublishedPrekey();
   void markPrekeyAsPublished();
   void forgetOldPrekey();
 
   void initializeInboundForReceivingSession(
       const std::string &targetDeviceId,
       const OlmBuffer &encryptedMessage,
       const OlmBuffer &idKeys,
       const bool overwrite = true);
   void initializeOutboundForSendingSession(
       const std::string &targetDeviceId,
       const OlmBuffer &idKeys,
       const OlmBuffer &preKeys,
       const OlmBuffer &preKeySignature,
       const OlmBuffer &oneTimeKey);
   bool hasSessionFor(const std::string &targetDeviceId);
   std::shared_ptr<Session> getSessionByDeviceId(const std::string &deviceId);
+  void removeSessionByDeviceId(const std::string &deviceId);
 
   Persist storeAsB64(const std::string &secretKey);
   void restoreFromB64(const std::string &secretKey, Persist persist);
 
   EncryptedData
   encrypt(const std::string &targetDeviceId, const std::string &content);
   std::string
   decrypt(const std::string &targetDeviceId, EncryptedData &encryptedData);
 
   std::string signMessage(const std::string &message);
   static void verifySignature(
       const std::string &publicKey,
       const std::string &message,
       const std::string &signature);
   std::optional<std::string> validatePrekey();
 };
 
 } // namespace crypto
 } // namespace comm
diff --git a/native/cpp/CommonCpp/CryptoTools/Session.cpp b/native/cpp/CommonCpp/CryptoTools/Session.cpp
index c1aeef787..add51af74 100644
--- a/native/cpp/CommonCpp/CryptoTools/Session.cpp
+++ b/native/cpp/CommonCpp/CryptoTools/Session.cpp
@@ -1,119 +1,161 @@
 #include "Session.h"
 #include "PlatformSpecificTools.h"
 
 #include <stdexcept>
 
 namespace comm {
 namespace crypto {
 
 OlmSession *Session::getOlmSession() {
   return reinterpret_cast<OlmSession *>(this->olmSessionBuffer.data());
 }
 
 std::unique_ptr<Session> Session::createSessionAsInitializer(
     OlmAccount *account,
     std::uint8_t *ownerIdentityKeys,
     const OlmBuffer &idKeys,
     const OlmBuffer &preKeys,
     const OlmBuffer &preKeySignature,
     const OlmBuffer &oneTimeKey) {
-  std::unique_ptr<Session> session(new Session(account, ownerIdentityKeys));
+  std::unique_ptr<Session> session(new Session());
 
   session->olmSessionBuffer.resize(::olm_session_size());
   ::olm_session(session->olmSessionBuffer.data());
 
   OlmBuffer randomBuffer;
   PlatformSpecificTools::generateSecureRandomBytes(
       randomBuffer,
       ::olm_create_outbound_session_random_length(session->getOlmSession()));
 
   if (-1 ==
       ::olm_create_outbound_session(
           session->getOlmSession(),
-          session->ownerUserAccount,
+          account,
           idKeys.data() + ID_KEYS_PREFIX_OFFSET,
           KEYSIZE,
           idKeys.data() + SIGNING_KEYS_PREFIX_OFFSET,
           KEYSIZE,
           preKeys.data(),
           KEYSIZE,
           preKeySignature.data(),
           SIGNATURESIZE,
           oneTimeKey.data(),
           KEYSIZE,
           randomBuffer.data(),
           randomBuffer.size())) {
     throw std::runtime_error(
         "error createOutbound => " +
         std::string{::olm_session_last_error(session->getOlmSession())});
   }
   return session;
 }
 
 std::unique_ptr<Session> Session::createSessionAsResponder(
     OlmAccount *account,
     std::uint8_t *ownerIdentityKeys,
     const OlmBuffer &encryptedMessage,
     const OlmBuffer &idKeys) {
-  std::unique_ptr<Session> session(new Session(account, ownerIdentityKeys));
+  std::unique_ptr<Session> session(new Session());
 
   OlmBuffer tmpEncryptedMessage(encryptedMessage);
   session->olmSessionBuffer.resize(::olm_session_size());
   ::olm_session(session->olmSessionBuffer.data());
   if (-1 ==
       ::olm_create_inbound_session(
           session->getOlmSession(),
-          session->ownerUserAccount,
+          account,
           tmpEncryptedMessage.data(),
           encryptedMessage.size())) {
     throw std::runtime_error(
         "error createInbound => " +
         std::string{::olm_session_last_error(session->getOlmSession())});
   }
 
   if (-1 == ::olm_remove_one_time_keys(account, session->getOlmSession())) {
     throw std::runtime_error(
         "error createInbound (remove oneTimeKey) => " +
         std::string{::olm_session_last_error(session->getOlmSession())});
   }
   return session;
 }
 
 OlmBuffer Session::storeAsB64(const std::string &secretKey) {
   size_t pickleLength = ::olm_pickle_session_length(this->getOlmSession());
   OlmBuffer pickle(pickleLength);
   size_t res = ::olm_pickle_session(
       this->getOlmSession(),
       secretKey.data(),
       secretKey.size(),
       pickle.data(),
       pickleLength);
   if (pickleLength != res) {
     throw std::runtime_error("error pickleSession => ::olm_pickle_session");
   }
   return pickle;
 }
 
-std::unique_ptr<Session> Session::restoreFromB64(
-    OlmAccount *account,
-    std::uint8_t *ownerIdentityKeys,
-    const std::string &secretKey,
-    OlmBuffer &b64) {
-  std::unique_ptr<Session> session(new Session(account, ownerIdentityKeys));
+std::unique_ptr<Session>
+Session::restoreFromB64(const std::string &secretKey, OlmBuffer &b64) {
+  std::unique_ptr<Session> session(new Session());
 
   session->olmSessionBuffer.resize(::olm_session_size());
   ::olm_session(session->olmSessionBuffer.data());
   if (-1 ==
       ::olm_unpickle_session(
           session->getOlmSession(),
           secretKey.data(),
           secretKey.size(),
           b64.data(),
           b64.size())) {
     throw std::runtime_error("error pickleSession => ::olm_unpickle_session");
   }
   return session;
 }
 
+std::string Session::decrypt(EncryptedData &encryptedData) {
+  OlmSession *session = this->getOlmSession();
+
+  OlmBuffer utilityBuffer(::olm_utility_size());
+  OlmUtility *olmUtility = ::olm_utility(utilityBuffer.data());
+
+  OlmBuffer messageHashBuffer(::olm_sha256_length(olmUtility));
+  ::olm_sha256(
+      olmUtility,
+      encryptedData.message.data(),
+      encryptedData.message.size(),
+      messageHashBuffer.data(),
+      messageHashBuffer.size());
+
+  OlmBuffer tmpEncryptedMessage(encryptedData.message);
+  size_t maxSize = ::olm_decrypt_max_plaintext_length(
+      session,
+      encryptedData.messageType,
+      tmpEncryptedMessage.data(),
+      tmpEncryptedMessage.size());
+
+  if (maxSize == -1) {
+    throw std::runtime_error{
+        "error decrypt_max_plaintext_length => " +
+        std::string{::olm_session_last_error(session)} + ". Hash: " +
+        std::string{messageHashBuffer.begin(), messageHashBuffer.end()}};
+  }
+
+  OlmBuffer decryptedMessage(maxSize);
+  size_t decryptedSize = ::olm_decrypt(
+      session,
+      encryptedData.messageType,
+      encryptedData.message.data(),
+      encryptedData.message.size(),
+      decryptedMessage.data(),
+      decryptedMessage.size());
+  if (decryptedSize == -1) {
+    throw std::runtime_error{
+        "error decrypt => " + std::string{::olm_session_last_error(session)} +
+        ". Hash: " +
+        std::string{messageHashBuffer.begin(), messageHashBuffer.end()}};
+  }
+  return std::string{(char *)decryptedMessage.data(), decryptedSize};
+}
+
 } // namespace crypto
 } // namespace comm
diff --git a/native/cpp/CommonCpp/CryptoTools/Session.h b/native/cpp/CommonCpp/CryptoTools/Session.h
index b359984d0..1c1f2ec22 100644
--- a/native/cpp/CommonCpp/CryptoTools/Session.h
+++ b/native/cpp/CommonCpp/CryptoTools/Session.h
@@ -1,46 +1,37 @@
 #pragma once
 
 #include <memory>
 #include <string>
 
 #include "Tools.h"
 
 #include "olm/olm.h"
 
 namespace comm {
 namespace crypto {
 
 class Session {
-  OlmAccount *ownerUserAccount;
-  std::uint8_t *ownerIdentityKeys;
-
   OlmBuffer olmSessionBuffer;
 
-  Session(OlmAccount *account, std::uint8_t *ownerIdentityKeys)
-      : ownerUserAccount(account), ownerIdentityKeys(ownerIdentityKeys) {
-  }
-
 public:
   static std::unique_ptr<Session> createSessionAsInitializer(
       OlmAccount *account,
       std::uint8_t *ownerIdentityKeys,
       const OlmBuffer &idKeys,
       const OlmBuffer &preKeys,
       const OlmBuffer &preKeySignature,
       const OlmBuffer &oneTimeKey);
   static std::unique_ptr<Session> createSessionAsResponder(
       OlmAccount *account,
       std::uint8_t *ownerIdentityKeys,
       const OlmBuffer &encryptedMessage,
       const OlmBuffer &idKeys);
   OlmBuffer storeAsB64(const std::string &secretKey);
-  static std::unique_ptr<Session> restoreFromB64(
-      OlmAccount *account,
-      std::uint8_t *ownerIdentityKeys,
-      const std::string &secretKey,
-      OlmBuffer &b64);
+  static std::unique_ptr<Session>
+  restoreFromB64(const std::string &secretKey, OlmBuffer &b64);
   OlmSession *getOlmSession();
+  std::string decrypt(EncryptedData &encryptedData);
 };
 
 } // namespace crypto
 } // namespace comm