diff --git a/android/build.gradle b/android/build.gradle
index da8455a..f058512 100644
--- a/android/build.gradle
+++ b/android/build.gradle
@@ -2,7 +2,8 @@
 
 def pEpEngineSrc = hasProperty('pEpEngineSrc') ? pEpEngineSrc : "../../pEpEngine"
 def buildAutomatic = hasProperty('buildAutomatic') ? buildAutomatic : "true"
-def threadsToUse = hasProperty('threadsToUse') ? threadsToUse : 1
+def threadsToUse = hasProperty('threadsToUse') ?
+        threadsToUse : Runtime.getRuntime().availableProcessors()
 
 def pEpEngineDB = new File(new File(pEpEngineSrc), 'db')
 
@@ -77,7 +78,7 @@ android {
             jniDebuggable true
             externalNativeBuild {
                 ndkBuild {
-                    arguments "-j${threadsToUse}", 'NDK_LOG=1'
+                    arguments "-j${threadsToUse}", 'NDK_LOG=1', 'NDK_DEBUG=1', 'NDEBUG=null'
                    // arguments '-B', 'NDK_DEBUG=1', 'NDEBUG=null', 'NDK_LOG=1'
                 }
             }
diff --git a/android/external/Makefile.conf b/android/external/Makefile.conf
index 60890e5..561134d 100644
--- a/android/external/Makefile.conf
+++ b/android/external/Makefile.conf
@@ -20,7 +20,7 @@ NETTLE_VERSION=3.4.1
 
 ### Git deps repos
 EXTERNAL_GIT_REPOS += libetpan|https://github.com/fdik/libetpan.git?HEAD
-EXTERNAL_GIT_REPOS += sequoia|https://gitlab.com/sequoia-pgp/sequoia.git?b5b783f58c9b6fdb26163cb7b236ee71cfef339e
+EXTERNAL_GIT_REPOS += sequoia|https://gitlab.com/sequoia-pgp/sequoia.git?de497f59570437d448b293769eb57bf7a9741f30
 
 ### Common variables
 #### Source code targets
diff --git a/src/basic_api.cc b/src/basic_api.cc
index 469b822..3d8d14d 100644
--- a/src/basic_api.cc
+++ b/src/basic_api.cc
@@ -9,6 +9,7 @@
 
 #include "throw_pEp_exception.hh"
 #include "jniutils.hh"
+#include "passphrase_callback.hh"
 
 extern "C" {
     using namespace pEp::JNIAdapter;
@@ -33,11 +34,18 @@ JNIEXPORT jbyteArray JNICALL Java_foundation_pEp_jniadapter_Engine__1trustwords(
     char *words;
     size_t wsize;
 
+    PEP_STATUS status = PEP_STATUS_OK;
+
     if (_ident->fpr == NULL || _ident->fpr[0] == 0) {
         if (_ident->me)
-            ::myself(session(), _ident);
+            status = passphraseWrap(::myself, session(), _ident);
         else
-            ::update_identity(session(), _ident);
+            status = passphraseWrap(::update_identity, session(), _ident);
+    }
+
+    if (status != PEP_STATUS_OK) {
+        throw_pEp_Exception(env, status);
+        return NULL;
     }
 
     if (_ident->fpr == NULL || _ident->fpr[0] == 0) {
@@ -51,7 +59,9 @@ JNIEXPORT jbyteArray JNICALL Java_foundation_pEp_jniadapter_Engine__1trustwords(
     else
         lang = "en";
 
-    PEP_STATUS status = ::trustwords(session(), _ident->fpr, lang, &words, &wsize, 10);
+    status = passphraseWrap(::trustwords,
+            session(), (const char *) _ident->fpr, lang, &words, &wsize, 10);
+
     if (status != PEP_STATUS_OK) {
         throw_pEp_Exception(env, status);
         return NULL;
@@ -76,7 +86,7 @@ JNIEXPORT jobject JNICALL Java_foundation_pEp_jniadapter_Engine__1myself(
 
     pEp_identity *_ident = to_identity(env, ident);
 
-    PEP_STATUS status = ::myself(session(), _ident);
+    PEP_STATUS status = passphraseWrap(::myself, session(), _ident);
 
     if (status != PEP_STATUS_OK) {
         LOGD("Failed Myself: 0x%04x\\n", status);
@@ -102,7 +112,7 @@ JNIEXPORT jobject JNICALL Java_foundation_pEp_jniadapter_Engine__1updateIdentity
 
     pEp_identity *_ident = to_identity(env, ident);
 
-    ::update_identity(session(), _ident);
+    passphraseWrap(::update_identity, session(), _ident);
 
     return from_identity(env, _ident);
 }
@@ -123,9 +133,9 @@ JNIEXPORT jobject JNICALL Java_foundation_pEp_jniadapter_Engine__1setOwnKey(
     std::lock_guard<std::mutex> l(*mutex_local);
 
     pEp_identity *_ident = to_identity(env, ident);
-    char *_fpr = to_string(env, fpr);
+    const char *_fpr = to_string(env, fpr);
 
-    PEP_STATUS status = ::set_own_key(session(), _ident, _fpr);
+    PEP_STATUS status = passphraseWrap(::set_own_key, session(), _ident, _fpr);
 
     if (status != PEP_STATUS_OK) {
         LOGD("Failed setOwnKey: 0x%04x\\n", status);
@@ -152,11 +162,18 @@ JNIEXPORT void JNICALL Java_foundation_pEp_jniadapter_Engine__1keyMistrusted(
 
     pEp_identity *_ident = to_identity(env, ident);
 
+    PEP_STATUS status = PEP_STATUS_OK;
+
     if (_ident->fpr == NULL || _ident->fpr[0] == 0) {
         if (_ident->me)
-            ::myself(session(), _ident);
+            status = passphraseWrap(::myself, session(), _ident);
         else
-            ::update_identity(session(), _ident);
+            status = passphraseWrap(::update_identity, session(), _ident);
+    }
+
+    if (status != PEP_STATUS_OK) {
+        throw_pEp_Exception(env, status);
+        return;
     }
 
     if (_ident->fpr == NULL || _ident->fpr[0] == 0) {
@@ -164,7 +181,7 @@ JNIEXPORT void JNICALL Java_foundation_pEp_jniadapter_Engine__1keyMistrusted(
         return;
     }
 
-    ::key_mistrusted(session(), _ident);
+    passphraseWrap(::key_mistrusted, session(), _ident);
 }
 
 JNIEXPORT void JNICALL Java_foundation_pEp_jniadapter_Engine__1keyResetTrust(
@@ -183,11 +200,18 @@ JNIEXPORT void JNICALL Java_foundation_pEp_jniadapter_Engine__1keyResetTrust(
 
     pEp_identity *_ident = to_identity(env, ident);
 
+    PEP_STATUS status = PEP_STATUS_OK;
+
     if (_ident->fpr == NULL || _ident->fpr[0] == 0) {
         if (_ident->me)
-            ::myself(session(), _ident);
+            status = passphraseWrap(::myself, session(), _ident);
         else
-            ::update_identity(session(), _ident);
+            status = passphraseWrap(::update_identity, session(), _ident);
+    }
+
+    if (status != PEP_STATUS_OK) {
+        throw_pEp_Exception(env, status);
+        return;
     }
 
     if (_ident->fpr == NULL || _ident->fpr[0] == 0) {
@@ -195,7 +219,7 @@ JNIEXPORT void JNICALL Java_foundation_pEp_jniadapter_Engine__1keyResetTrust(
         return;
     }
 
-    ::key_reset_trust(session(), _ident);
+    passphraseWrap(::key_reset_trust, session(), _ident);
 }
 
 JNIEXPORT void JNICALL Java_foundation_pEp_jniadapter_Engine__1trustPersonalKey(
@@ -214,11 +238,18 @@ JNIEXPORT void JNICALL Java_foundation_pEp_jniadapter_Engine__1trustPersonalKey(
 
     pEp_identity *_ident = to_identity(env, ident);
 
+    PEP_STATUS status = PEP_STATUS_OK;
+
     if (_ident->fpr == NULL || _ident->fpr[0] == 0) {
         if (_ident->me)
-            ::myself(session(), _ident);
+            status = passphraseWrap(::myself, session(), _ident);
         else
-            ::update_identity(session(), _ident);
+            status = passphraseWrap(::update_identity, session(), _ident);
+    }
+
+    if (status != PEP_STATUS_OK) {
+        throw_pEp_Exception(env, status);
+        return;
     }
 
     if (_ident->fpr == NULL || _ident->fpr[0] == 0) {
@@ -226,7 +257,7 @@ JNIEXPORT void JNICALL Java_foundation_pEp_jniadapter_Engine__1trustPersonalKey(
         return;
     }
 
-    ::trust_personal_key(session(), _ident);
+    passphraseWrap(::trust_personal_key, session(), _ident);
 }
 
 JNIEXPORT void JNICALL Java_foundation_pEp_jniadapter_Engine__1trustOwnKey(
@@ -250,7 +281,7 @@ JNIEXPORT void JNICALL Java_foundation_pEp_jniadapter_Engine__1trustOwnKey(
         return;
     }
 
-    ::trust_own_key(session(), _ident);
+    passphraseWrap(::trust_own_key, session(), _ident);
 }
 
 JNIEXPORT jobject JNICALL Java_foundation_pEp_jniadapter_Engine__1importKey(
@@ -268,7 +299,7 @@ JNIEXPORT jobject JNICALL Java_foundation_pEp_jniadapter_Engine__1importKey(
     std::lock_guard<std::mutex> l(*mutex_local);
 
     size_t _size = (size_t) env->GetArrayLength(key);
-    char *_key = (char *) env->GetByteArrayElements(key, NULL);
+    const char *_key = (char *) env->GetByteArrayElements(key, NULL);
 
     if(_key == NULL){
         throw_pEp_Exception(env, PEP_OUT_OF_MEMORY);
@@ -277,7 +308,7 @@ JNIEXPORT jobject JNICALL Java_foundation_pEp_jniadapter_Engine__1importKey(
 
     identity_list *_identities;
 
-    PEP_STATUS status = ::import_key(session(), _key, _size, &_identities);
+    PEP_STATUS status =  passphraseWrap(::import_key, session(), _key, _size, &_identities);
     if (status != PEP_STATUS_OK && status != PEP_KEY_IMPORTED) {
         throw_pEp_Exception(env, status);
         return NULL;
@@ -342,14 +373,14 @@ JNIEXPORT void JNICALL Java_foundation_pEp_jniadapter_Engine__1blacklist_1add(
     }
     std::lock_guard<std::mutex> l(*mutex_local);
 
-    char *_fpr = to_string(env, fpr);
+    const char *_fpr = to_string(env, fpr);
 
     if(_fpr == NULL){
         throw_pEp_Exception(env, PEP_OUT_OF_MEMORY);
         return;
     }
 
-    PEP_STATUS status = ::blacklist_add(session(), _fpr);
+    PEP_STATUS status = passphraseWrap(::blacklist_add, session(), _fpr);
     if (status != PEP_STATUS_OK) {
         throw_pEp_Exception(env, status);
         return;
@@ -371,14 +402,14 @@ JNIEXPORT void JNICALL Java_foundation_pEp_jniadapter_Engine__1blacklist_1delete
     }
     std::lock_guard<std::mutex> l(*mutex_local);
 
-    char *_fpr = to_string(env, fpr);
+    const char *_fpr = to_string(env, fpr);
 
     if(_fpr == NULL){
         throw_pEp_Exception(env, PEP_OUT_OF_MEMORY);
         return;
     }
 
-    PEP_STATUS status = ::blacklist_delete(session(), _fpr);
+    PEP_STATUS status = passphraseWrap(::blacklist_delete, session(), _fpr);
     if (status != PEP_STATUS_OK) {
         throw_pEp_Exception(env, status);
         return;
@@ -400,7 +431,7 @@ JNIEXPORT jboolean JNICALL Java_foundation_pEp_jniadapter_Engine__1blacklist_1is
     }
     std::lock_guard<std::mutex> l(*mutex_local);
 
-    char *_fpr = to_string(env, fpr);
+    const char *_fpr = to_string(env, fpr);
     bool _listed = 0;
 
     if(_fpr == NULL){
@@ -408,7 +439,7 @@ JNIEXPORT jboolean JNICALL Java_foundation_pEp_jniadapter_Engine__1blacklist_1is
         return 0;
     }
 
-    PEP_STATUS status = ::blacklist_is_listed(session(), _fpr, &_listed);
+    PEP_STATUS status = passphraseWrap(::blacklist_is_listed, session(), _fpr, &_listed);
     if (status != PEP_STATUS_OK) {
         throw_pEp_Exception(env, status);
         return 0;
@@ -435,7 +466,7 @@ JNIEXPORT jbyteArray JNICALL Java_foundation_pEp_jniadapter_Engine__1getCrashdum
     int _maxlines = (int) maxlines;
     char *_logdata;
 
-    PEP_STATUS status = ::get_crashdump_log(session(), _maxlines, &_logdata);
+    PEP_STATUS status = passphraseWrap(::get_crashdump_log, session(), _maxlines, &_logdata);
     if ((status > PEP_STATUS_OK && status < PEP_UNENCRYPTED) ||
             status < PEP_STATUS_OK ||
             status >= PEP_TRUSTWORD_NOT_FOUND) {
@@ -525,6 +556,7 @@ JNIEXPORT void JNICALL Java_foundation_pEp_jniadapter_Engine__1config_1passphras
         return ;
     }
 
+
 }
 
 } // extern "C"
diff --git a/src/gen_cpp_Engine.ysl2 b/src/gen_cpp_Engine.ysl2
index 7dd15d9..3e52f11 100644
--- a/src/gen_cpp_Engine.ysl2
+++ b/src/gen_cpp_Engine.ysl2
@@ -270,6 +270,7 @@ tstylesheet {
         const "dir", "name(*[1])";
         const "type", "name(*[2])";
         const "name", "name(*[3])";
+        const "const", "name(*[4])";
 
         choose {
             when "$type = 'message'"
@@ -280,10 +281,18 @@ tstylesheet {
                 | bool _«$name» = (bool) «$name»;
             when "$type='int'"
                 | int _«$name» = (int) «$name»;
+            when "$type='uint'"
+                | auto _«$name» = (unsigned int) «$name»;
             when "$type='string'"
                 | const char *_«$name» = to_string(env, «$name»);
-            otherwise
-                | √$type *_«$name» = to_«$type»(env, «$name»);
+            otherwise {
+                choose {
+                    when "$const"
+                        | const √$type *_«$name» = to_«$type»(env, «$name»);
+                    otherwise
+                        | √$type *_«$name» = to_«$type»(env, «$name»);
+                }
+            }
         }
     }
 
diff --git a/src/pEp.yml2 b/src/pEp.yml2
index 8810026..c3022fa 100644
--- a/src/pEp.yml2
+++ b/src/pEp.yml2
@@ -119,14 +119,14 @@ namespace pEp {
                 inout int flags
             );
 
-        method re_evaluate_message_rating(
+        method cached=true re_evaluate_message_rating(
                 in message src,
-                Cconst stringlist x_keylist "NULL",
+                Cconst stringlist x_keylist "static_cast<stringlist_t*>(nullptr)",
                 Cconst Rating x_enc_status "PEP_rating_undefined",
                 returns Rating rating
             );
 
-        method outgoing_message_rating(
+        method cached=true outgoing_message_rating(
                 in message msg,
                 returns Rating rating
             );
@@ -136,18 +136,18 @@ namespace pEp {
                 returns Rating rating
             );
 
-        method get_identity(
+        method cached=true get_identity(
                 in string address,
                 in string userid,
                 returns identity ident
             );
 
-        method identity_rating(
+        method cached=true identity_rating(
                 in identity ident,
                 returns Rating rating
             );
 
-        method blacklist_retrieve(
+        method cached=true blacklist_retrieve(
                 returns stringlist blacklist
             );
 
@@ -157,34 +157,36 @@ namespace pEp {
                 returns identity ident 
             );
 
-        method OpenPGP_list_keyinfo(
+        method cached=true OpenPGP_list_keyinfo(
                 in string pattern,
                 returns stringpairlist keyinfoList
             );
 
-        method set_identity_flags(
+        //TODO Move to use IdentityFlag instead of ints
+        method cached=true set_identity_flags(
                 in identity ident,
-                in int flags
+                in uint flags
             );
 
-        method unset_identity_flags(
+        method cached=true unset_identity_flags(
                 in identity ident,
-                in int flags
+                in uint flags
             );
 
-        method own_identities_retrieve(
+        method cached=true own_identities_retrieve(
                 returns identitylist identities
             );
 
-        method get_trustwords(
-                in identity id1,
-                in identity id2,
+
+        method cached=true get_trustwords(
+                in identity id1 const,
+                in identity id2 const,
                 in string lang,
                 returns sstring words,
                 in bool full
             );
 
-        method get_trustwords_for_fprs(
+        method cached=true get_trustwords_for_fprs(
                 in string fpr1,
                 in string fpr2,
                 in string lang,
@@ -201,13 +203,13 @@ namespace pEp {
                 in bool full
             );
 
-        method get_languagelist(
+        method cached=true get_languagelist(
                 returns string languagelist
             );
 
         // this function is not related to key reset
 
-        method key_reset_trust(
+        method cached=true key_reset_trust(
                 in identity ident
             );
 
@@ -223,14 +225,14 @@ namespace pEp {
 
         method cached=true key_reset_all_own_keys();
                 
-        method deliverHandshakeResult(
+        method cached=true deliverHandshakeResult(
                 in SyncHandshakeResult shr,
-                in identitylist identities
+                in identitylist identities const
             );
 
-        method leave_device_group();
+        method cached=true leave_device_group();
 
-        method enable_identity_for_sync(
+        method cached=true enable_identity_for_sync(
                 in identity ident
             );
 
diff --git a/src/passphrase_callback.hh b/src/passphrase_callback.hh
index 357b2c6..8482077 100644
--- a/src/passphrase_callback.hh
+++ b/src/passphrase_callback.hh
@@ -1,3 +1,5 @@
+#pragma once
+#include <pEp/passphrase_cache.hh>
 
 
 namespace pEp {
@@ -5,5 +7,9 @@ namespace pEp {
 
     char* passphraseRequiredCallback();
 
+        template<typename... A> PEP_STATUS passphraseWrap(
+                PEP_STATUS f(PEP_SESSION, A...), PEP_SESSION session, A... a);
     };
-};
\ No newline at end of file
+};
+
+#include "passphrase_callback.hxx"
\ No newline at end of file
diff --git a/src/passphrase_callback.hxx b/src/passphrase_callback.hxx
new file mode 100644
index 0000000..20bfa36
--- /dev/null
+++ b/src/passphrase_callback.hxx
@@ -0,0 +1,41 @@
+#pragma once
+
+#include "passphrase_callback.hh"
+
+namespace pEp {
+    namespace JNIAdapter {
+
+        template<typename... A> PEP_STATUS passphraseWrap(
+                PEP_STATUS f(PEP_SESSION, A...), PEP_SESSION session, A... a) {
+            pEpLog("cached passphrase mode");
+            bool retryAgain = false;
+            int maxRetries = 3;
+            int retryCount = 0;
+            PEP_STATUS status;
+            do {
+                // the actual target function
+                pEpLog("calling passphrase_cache.api from basic_api");
+                status = passphrase_cache.api(f, session, a...);
+                pEpLog("PEP_STATUS:" << status);
+                if (status == PEP_PASSPHRASE_REQUIRED || status == PEP_WRONG_PASSPHRASE) {
+                    pEpLog("none of the cached passphrases worked");
+                    if (retryCount < maxRetries) {
+                        // call the app
+                        char *_passphrase = passphraseRequiredCallback();
+                        pEpLog("callback returned, config_passphrase() with new passphrase");
+                        PEP_STATUS status = ::config_passphrase(session,
+                                                                passphrase_cache.add(_passphrase));
+                        retryAgain = true;
+                        retryCount++;
+                    } else {
+                        pEpLog("max retries reached:" << maxRetries);
+                        retryAgain = false;
+                    }
+                } else {
+                    retryAgain = false;
+                }
+            } while (retryAgain);
+            return status;
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/types_c.ysl2 b/src/types_c.ysl2
index 1ec81ea..0d2497f 100644
--- a/src/types_c.ysl2
+++ b/src/types_c.ysl2
@@ -17,6 +17,7 @@ function "toC" {
         when "$type='Rating'" > PEP_rating
         when "$type='SyncHandshakeResult'" > sync_handshake_result
         when "$type='CipherSuite'" > PEP_CIPHER_SUITE
+        when "$type='uint'" > uint
 
         otherwise value "$type";
     }
@@ -31,6 +32,7 @@ function "jni_type" {
         when "$type = 'string' or $type = 'sstring'" > jbyteArray
         when "$type='bool'" > jboolean
         when "$type='int'" > jint
+        when "$type='uint'" > jint
         otherwise > jobject
     }
 }
diff --git a/src/types_java.ysl2 b/src/types_java.ysl2
index a6806e5..6e67660 100644
--- a/src/types_java.ysl2
+++ b/src/types_java.ysl2
@@ -4,6 +4,7 @@ function "toJava" {
     choose {
         when "$type='bool'" > Boolean
         when "$type='int'" > int
+        when "$type='uint'" > int
         when "$type='string' or $type='sstring'" > String
         when "$type='timestamp'" > Date
         when "$type='void'" > void