diff --git a/passphrase_cache.cc b/passphrase_cache.cc
index 70dc084..de7f2ad 100644
--- a/passphrase_cache.cc
+++ b/passphrase_cache.cc
@@ -81,5 +81,27 @@ namespace pEp {
         --_which;
         return _which->passphrase.c_str();
     }
+
+	PEP_STATUS PassphraseCache::messageToSend(PassphraseCache&& cache, PEP_SESSION session)
+	{
+        static pEp::PassphraseCache _copy;
+        static bool new_copy = true;
+        if (new_copy) {
+            _copy = cache;
+            new_copy = false;
+        }
+        try {
+            ::config_passphrase(session, _copy.latest_passphrase());
+            return PEP_STATUS_OK;
+        }
+        catch (pEp::PassphraseCache::Empty&) {
+            new_copy = true;
+            return PEP_PASSPHRASE_REQUIRED;
+        }
+        catch (pEp::PassphraseCache::Exhausted&) {
+            new_copy = true;
+            return PEP_WRONG_PASSPHRASE;
+        }
+	}
 };
 
diff --git a/passphrase_cache.hh b/passphrase_cache.hh
index 3205a72..7985072 100644
--- a/passphrase_cache.hh
+++ b/passphrase_cache.hh
@@ -48,6 +48,19 @@ namespace pEp {
 
         const char *add(std::string passphrase);
 
+        // get all passphrases in cache from latest to oldest one by each call
+        // this function is throwing PassphraseCache::Empty when cache is empty
+        // and PassphraseCache::Exhausted when no passphrases are left, then
+        // starts over
+
+        const char *latest_passphrase();
+
+        // call this function inside the messageToSend() implementation of the adapter
+        // this function is using latest_passphrase() to test one passphrase after the
+        // other until the cache is exhausted
+
+        static PEP_STATUS messageToSend(PassphraseCache&& cache, PEP_SESSION session);
+
         // for each passphrase call the callee until it returns true for a
         // matching passphrase or no passphrases are left
         // always tests empty passphrase first
@@ -56,13 +69,6 @@ namespace pEp {
         using passphrase_callee = std::function<bool(std::string)>;
         bool for_each_passphrase(const passphrase_callee& callee);
 
-        // get all passphrases in cache from latest to oldest one by each call
-        // this function is throwing PassphraseCache::Empty when cache is empty
-        // and PassphraseCache::Exhausted when no passphrases are left, then
-        // starts over
-
-        const char *latest_passphrase();
-
         // convenience functions
         // i.e.
         // status = cache.api(::encrypt_message, session, src, extra, dst, enc_format, flags)