diff --git a/CMakeLists.txt b/CMakeLists.txt
index 79d8cafb..3b471689 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -58,6 +58,10 @@ else()
     set(static_default ON)
 endif()
 
+if(EMSCRIPTEN)
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -sNO_DISABLE_EXCEPTION_CATCHING ")
+endif()
+
 option(BUILD_STATIC_DEPS "Build all dependencies statically rather than trying to link to them on the system" ${static_default})
 option(STATIC_BUNDLE "Build a single static .a containing everything (both code and dependencies)" ${static_default})
 
diff --git a/include/session/config/groups/keys.hpp b/include/session/config/groups/keys.hpp
index 5eaa27bb..1eb6f01e 100644
--- a/include/session/config/groups/keys.hpp
+++ b/include/session/config/groups/keys.hpp
@@ -491,6 +491,12 @@ class Keys : public ConfigSig {
             std::span<const unsigned char> signing_value,
             bool binary = false) const;
 
+    static Keys::swarm_auth swarm_subaccount_sign_as_user(
+            std::span<const unsigned char> user_ed25519_sk,
+            std::span<const unsigned char> msg,
+            std::span<const unsigned char> sign_val,
+            bool binary = false);
+
     /// API: groups/Keys::swarm_subaccount_token
     ///
     /// Constructs the subaccount token for a session id.  The main use of this is to submit a swarm
diff --git a/src/config/groups/keys.cpp b/src/config/groups/keys.cpp
index 86a7fd14..ab7eebb1 100644
--- a/src/config/groups/keys.cpp
+++ b/src/config/groups/keys.cpp
@@ -23,6 +23,7 @@
 #include "session/config/groups/members.hpp"
 #include "session/multi_encrypt.hpp"
 #include "session/session_encrypt.hpp"
+#include "session/util.hpp"
 #include "session/xed25519.hpp"
 
 using namespace std::literals;
@@ -654,16 +655,14 @@ std::vector<unsigned char> Keys::swarm_subaccount_token(
     return out;
 }
 
-Keys::swarm_auth Keys::swarm_subaccount_sign(
+Keys::swarm_auth Keys::swarm_subaccount_sign_as_user(
+        std::span<const unsigned char> user_ed25519_sk,
         std::span<const unsigned char> msg,
         std::span<const unsigned char> sign_val,
-        bool binary) const {
+        bool binary) {
     if (sign_val.size() != 100)
         throw std::logic_error{"Invalid signing value: size is wrong"};
 
-    if (!_sign_pk)
-        throw std::logic_error{"Unable to verify: group pubkey is not set (!?)"};
-
     Keys::swarm_auth result;
     auto& [token, sub_sig, sig] = result;
 
@@ -776,6 +775,16 @@ Keys::swarm_auth Keys::swarm_subaccount_sign(
     return result;
 }
 
+Keys::swarm_auth Keys::swarm_subaccount_sign(
+        std::span<const unsigned char> msg,
+        std::span<const unsigned char> sign_val,
+        bool binary) const {
+    auto user_ed25519_sk_buf = this->user_ed25519_sk.data();
+    std::span<const unsigned char> user_ed25519_sk(
+            user_ed25519_sk_buf, this->user_ed25519_sk.size());
+    return Keys::swarm_subaccount_sign_as_user(user_ed25519_sk, msg, sign_val, binary);
+}
+
 bool Keys::swarm_verify_subaccount(
         std::span<const unsigned char> sign_val, bool write, bool del) const {
     if (!_sign_pk)