diff --git a/libsession-util/src/main/cpp/group_keys.cpp b/libsession-util/src/main/cpp/group_keys.cpp
index f68b93ccf7..240635b939 100644
--- a/libsession-util/src/main/cpp/group_keys.cpp
+++ b/libsession-util/src/main/cpp/group_keys.cpp
@@ -6,18 +6,58 @@ extern "C"
 JNIEXPORT jobject JNICALL
 Java_network_loki_messenger_libsession_1util_GroupKeysConfig_00024Companion_newInstance(JNIEnv *env,
                                                                                         jobject thiz,
-                                                                                        jbyteArray public_key,
-                                                                                        jbyteArray secret_key,
+                                                                                        jbyteArray user_secret_key,
+                                                                                        jbyteArray group_public_key,
+                                                                                        jbyteArray group_secret_key,
                                                                                         jbyteArray initial_dump,
-                                                                                        jobject info,
-                                                                                        jobject members) {
-    // TODO: implement newInstance()
+                                                                                        jobject info_jobject,
+                                                                                        jobject members_jobject) {
+    std::lock_guard lock{util::util_mutex_};
+    auto user_key_bytes = util::ustring_from_bytes(env, user_secret_key);
+    auto pub_key_bytes = util::ustring_from_bytes(env, group_public_key);
+    std::optional<session::ustring> secret_key_optional{std::nullopt};
+    std::optional<session::ustring> initial_dump_optional{std::nullopt};
+    if (group_secret_key != nullptr) {
+        auto secret_key_bytes = util::ustring_from_bytes(env, group_secret_key);
+        secret_key_optional = secret_key_bytes;
+    }
+    if (initial_dump != nullptr) {
+        auto initial_dump_bytes = util::ustring_from_bytes(env, initial_dump);
+        initial_dump_optional = initial_dump_bytes;
+    }
+
+    auto info = ptrToInfo(env, info_jobject);
+    auto members = ptrToMembers(env, members_jobject);
+
+    auto* keys = new session::config::groups::Keys(user_key_bytes,
+                                                   pub_key_bytes,
+                                                   secret_key_optional,
+                                                   initial_dump_optional,
+                                                   *info,
+                                                   *members);
+
+    jclass groupKeysConfig = env->FindClass("network/loki/messenger/libsession_util/GroupKeysConfig");
+    jmethodID constructor = env->GetMethodID(groupKeysConfig, "<init>", "(J)V");
+    jobject newConfig = env->NewObject(groupKeysConfig, constructor, reinterpret_cast<jlong>(keys));
+
+    return newConfig;
 }
 
 extern "C"
 JNIEXPORT jobject JNICALL
 Java_network_loki_messenger_libsession_1util_GroupKeysConfig_groupKeys(JNIEnv *env, jobject thiz) {
-    // TODO: implement groupKeys()
+    std::lock_guard lock{util::util_mutex_};
+    auto config = ptrToKeys(env, thiz);
+    auto keys = config->group_keys();
+    jclass stack = env->FindClass("java/util/Stack");
+    jmethodID init = env->GetMethodID(stack, "<init>", "()V");
+    jobject our_stack = env->NewObject(stack, init);
+    jmethodID push = env->GetMethodID(stack, "push", "(Ljava/lang/Object;)Ljava/lang/Object;");
+    for (auto& key : keys) {
+        auto key_bytes = util::bytes_from_ustring(env, key.data());
+        env->CallObjectMethod(our_stack, push, key_bytes);
+    }
+    return our_stack;
 }
 
 extern "C"
@@ -28,6 +68,7 @@ Java_network_loki_messenger_libsession_1util_GroupKeysConfig_loadKey(JNIEnv *env
                                                                      jlong timestamp_ms,
                                                                      jobject info_jobject,
                                                                      jobject members_jobject) {
+    std::lock_guard lock{util::util_mutex_};
     auto keys = ptrToKeys(env, thiz);
     auto data_bytes = util::ustring_from_bytes(env, data);
     auto msg_bytes = util::ustring_from_bytes(env, msg_id);
@@ -39,6 +80,7 @@ Java_network_loki_messenger_libsession_1util_GroupKeysConfig_loadKey(JNIEnv *env
 extern "C"
 JNIEXPORT jboolean JNICALL
 Java_network_loki_messenger_libsession_1util_GroupKeysConfig_needsRekey(JNIEnv *env, jobject thiz) {
+    std::lock_guard lock{util::util_mutex_};
     auto keys = ptrToKeys(env, thiz);
     return keys->needs_rekey();
 }
@@ -46,6 +88,7 @@ Java_network_loki_messenger_libsession_1util_GroupKeysConfig_needsRekey(JNIEnv *
 extern "C"
 JNIEXPORT jbyteArray JNICALL
 Java_network_loki_messenger_libsession_1util_GroupKeysConfig_pendingKey(JNIEnv *env, jobject thiz) {
+    std::lock_guard lock{util::util_mutex_};
     auto keys = ptrToKeys(env, thiz);
     auto pending = keys->pending_key();
     if (!pending) {
@@ -59,6 +102,7 @@ extern "C"
 JNIEXPORT jbyteArray JNICALL
 Java_network_loki_messenger_libsession_1util_GroupKeysConfig_pendingPush(JNIEnv *env,
                                                                          jobject thiz) {
+    std::lock_guard lock{util::util_mutex_};
     auto keys = ptrToKeys(env, thiz);
     auto pending = keys->pending_config();
     if (!pending) {
@@ -72,6 +116,7 @@ extern "C"
 JNIEXPORT jbyteArray JNICALL
 Java_network_loki_messenger_libsession_1util_GroupKeysConfig_rekey(JNIEnv *env, jobject thiz,
                                                                    jobject info_jobject, jobject members_jobject) {
+    std::lock_guard lock{util::util_mutex_};
     auto keys = ptrToKeys(env, thiz);
     auto info = ptrToInfo(env, info_jobject);
     auto members = ptrToMembers(env, members_jobject);
diff --git a/libsession-util/src/main/cpp/group_members.cpp b/libsession-util/src/main/cpp/group_members.cpp
index 001ed56e13..32d08e5aa6 100644
--- a/libsession-util/src/main/cpp/group_members.cpp
+++ b/libsession-util/src/main/cpp/group_members.cpp
@@ -5,6 +5,7 @@ JNIEXPORT jobject JNICALL
 Java_network_loki_messenger_libsession_1util_GroupMemberConfig_00024Companion_newInstance(
         JNIEnv *env, jobject thiz, jbyteArray pub_key, jbyteArray secret_key,
         jbyteArray initial_dump) {
+    std::lock_guard lock{util::util_mutex_};
     auto pub_key_bytes = util::ustring_from_bytes(env, pub_key);
     std::optional<session::ustring> secret_key_optional{std::nullopt};
     std::optional<session::ustring> initial_dump_optional{std::nullopt};
@@ -29,6 +30,7 @@ Java_network_loki_messenger_libsession_1util_GroupMemberConfig_00024Companion_ne
 extern "C"
 JNIEXPORT jobject JNICALL
 Java_network_loki_messenger_libsession_1util_GroupMemberConfig_all(JNIEnv *env, jobject thiz) {
+    std::lock_guard lock{util::util_mutex_};
     auto config = ptrToMembers(env, thiz);
     jclass stack = env->FindClass("java/util/Stack");
     jmethodID init = env->GetMethodID(stack, "<init>", "()V");
@@ -54,6 +56,7 @@ extern "C"
 JNIEXPORT jobject JNICALL
 Java_network_loki_messenger_libsession_1util_GroupMemberConfig_get(JNIEnv *env, jobject thiz,
                                                                    jstring pub_key_hex) {
+    std::lock_guard lock{util::util_mutex_};
     auto config = ptrToMembers(env, thiz);
     auto pub_key_bytes = env->GetStringUTFChars(pub_key_hex, nullptr);
     auto member = config->get(pub_key_bytes);
@@ -70,6 +73,7 @@ JNIEXPORT jobject JNICALL
 Java_network_loki_messenger_libsession_1util_GroupMemberConfig_getOrConstruct(JNIEnv *env,
                                                                               jobject thiz,
                                                                               jstring pub_key_hex) {
+    std::lock_guard lock{util::util_mutex_};
     auto config = ptrToMembers(env, thiz);
     auto pub_key_bytes = env->GetStringUTFChars(pub_key_hex, nullptr);
     auto member = config->get_or_construct(pub_key_bytes);
@@ -82,6 +86,7 @@ extern "C"
 JNIEXPORT void JNICALL
 Java_network_loki_messenger_libsession_1util_GroupMemberConfig_set(JNIEnv *env, jobject thiz,
                                                                    jobject group_member) {
+    std::lock_guard lock{util::util_mutex_};
     auto config = ptrToMembers(env, thiz);
     auto deserialized = util::deserialize_group_member(env, group_member);
     config->set(deserialized);
diff --git a/libsession-util/src/main/java/network/loki/messenger/libsession_util/Config.kt b/libsession-util/src/main/java/network/loki/messenger/libsession_util/Config.kt
index 19ee03c897..914169c532 100644
--- a/libsession-util/src/main/java/network/loki/messenger/libsession_util/Config.kt
+++ b/libsession-util/src/main/java/network/loki/messenger/libsession_util/Config.kt
@@ -10,6 +10,7 @@ import network.loki.messenger.libsession_util.util.UserPic
 import org.session.libsignal.protos.SignalServiceProtos.SharedConfigMessage.Kind
 import org.session.libsignal.utilities.IdPrefix
 import org.session.libsignal.utilities.Log
+import java.util.Stack
 
 
 sealed class ConfigBase(protected val /* yucky */ pointer: Long) {
@@ -245,7 +246,7 @@ class GroupMemberConfig(pointer: Long): ConfigBase(pointer) {
             initialDump: ByteArray?
         ): GroupMemberConfig
     }
-    external fun all(): List<GroupMember>
+    external fun all(): Stack<GroupMember>
     external fun erase(groupMember: GroupMember): Boolean
     external fun get(pubKeyHex: String): GroupMember?
     external fun getOrConstruct(pubKeyHex: String): GroupMember
@@ -258,14 +259,15 @@ class GroupKeysConfig(pointer: Long): ConfigBase(pointer) {
             System.loadLibrary("session_util")
         }
         external fun newInstance(
-            publicKey: ByteArray,
-            secretKey: ByteArray?,
+            userSecretKey: ByteArray,
+            groupPublicKey: ByteArray,
+            groupSecretKey: ByteArray?,
             initialDump: ByteArray?,
             info: GroupInfoConfig,
             members: GroupMemberConfig
         ): GroupKeysConfig
     }
-    external fun groupKeys(): List<ByteArray>
+    external fun groupKeys(): Stack<ByteArray>
     external fun loadKey(data: ByteArray,
                          msgId: ByteArray,
                          timestampMs: Long,