diff --git a/Adapter.cc b/Adapter.cc
index aa5bdb3..b545f54 100644
--- a/Adapter.cc
+++ b/Adapter.cc
@@ -7,6 +7,7 @@
 #include <assert.h>
 #include "status_to_string.hh"
 #include "pEpLog.hh"
+#include "passphrase_cache.hh"
 
 using namespace std;
 
@@ -82,6 +83,11 @@ namespace pEp {
             return 0;
         }
 
+        PEP_STATUS _ensure_passphrase(PEP_SESSION session, const char *fpr)
+        {
+            return passphrase_cache.ensure_passphrase(session, fpr);
+        }
+
         // threshold: max waiting time in seconds
         SYNC_EVENT _retrieve_next_sync_event(void *management, unsigned threshold)
         {
@@ -120,7 +126,7 @@ namespace pEp {
 
                 case init:
                     if (!_session)
-                        status = ::init(&_session, _messageToSend, _inject_sync_event);
+                        status = ::init(&_session, _messageToSend, _inject_sync_event, _ensure_passphrase);
                     break;
 
                 default:
diff --git a/Adapter.hh b/Adapter.hh
index d5faac2..d71fb33 100644
--- a/Adapter.hh
+++ b/Adapter.hh
@@ -24,6 +24,7 @@ namespace pEp {
 
     namespace Adapter {
         int _inject_sync_event(SYNC_EVENT ev, void *management);
+        PEP_STATUS _ensure_passphrase(PEP_SESSION session, const char *fpr);
 
         template<class T = void>
         void startup(
diff --git a/passphrase_cache.cc b/passphrase_cache.cc
index 6c5a806..3d1815b 100644
--- a/passphrase_cache.cc
+++ b/passphrase_cache.cc
@@ -153,5 +153,21 @@ namespace pEp {
             return PEP_WRONG_PASSPHRASE;
         }
 	}
+
+    PEP_STATUS PassphraseCache::ensure_passphrase(PEP_SESSION session, std::string fpr)
+    {
+        PEP_STATUS status = PEP_STATUS_OK;
+
+        for_each_passphrase([&](std::string passphrase) {
+            status = ::config_passphrase(session, passphrase.c_str());
+            if (status)
+                return true;
+
+            status = ::probe_encrypt(session, fpr.c_str());
+            return status == PEP_STATUS_OK;
+        });
+
+        return status;
+    }
 };
 
diff --git a/passphrase_cache.hh b/passphrase_cache.hh
index 08cc3a0..b857590 100644
--- a/passphrase_cache.hh
+++ b/passphrase_cache.hh
@@ -73,6 +73,7 @@ namespace pEp {
         static const char *latest_passphrase(PassphraseCache& _cache);
         using passphrase_callee = std::function<bool(std::string)>;
         bool for_each_passphrase(const passphrase_callee& callee);
+        PEP_STATUS ensure_passphrase(PEP_SESSION session, std::string fpr);
 
     protected:
         void cleanup();