libs:

	libaxolotl:
		updated libaxolotl (libsignal-c) from (https://github.com/WhisperSystems/libsignal-protocol-c)

1 files changed, 87 insertions, 602 deletions

diff --git a/libs/libaxolotl/src/session_builder.c b/libs/libaxolotl/src/session_builder.c
index b962c21b5f..2bfd62015f 100644
--- a/libs/libaxolotl/src/session_builder.c
+++ b/libs/libaxolotl/src/session_builder.c
@@ -1,36 +1,29 @@
 #include "session_builder.h"
+#include "session_builder_internal.h"
 
 #include <assert.h>
 #include <string.h>
-#include "axolotl_internal.h"
 #include "session_pre_key.h"
 #include "session_record.h"
 #include "session_state.h"
 #include "ratchet.h"
 #include "protocol.h"
 #include "key_helper.h"
-
-#define MIN(a,b) (((a)<(b))?(a):(b))
+#include "signal_protocol_internal.h"
 
 struct session_builder
 {
-    axolotl_store_context *store;
-    const axolotl_address *remote_address;
-    axolotl_context *global_context;
+    signal_protocol_store_context *store;
+    const signal_protocol_address *remote_address;
+    signal_context *global_context;
 };
 
-static int session_builder_process_pre_key_whisper_message_v2(session_builder *builder,
-        session_record *record, pre_key_whisper_message *message, uint32_t *unsigned_pre_key_id);
-static int session_builder_process_pre_key_whisper_message_v3(session_builder *builder,
-        session_record *record, pre_key_whisper_message *message, uint32_t *unsigned_pre_key_id);
-static int session_builder_process_initiate(session_builder *builder,
-        key_exchange_message *message, key_exchange_message **response_message);
-static int session_builder_process_response(session_builder *builder,
-        key_exchange_message *message);
+static int session_builder_process_pre_key_signal_message_v3(session_builder *builder,
+        session_record *record, pre_key_signal_message *message, uint32_t *unsigned_pre_key_id);
 
 int session_builder_create(session_builder **builder,
-        axolotl_store_context *store, const axolotl_address *remote_address,
-        axolotl_context *global_context)
+        signal_protocol_store_context *store, const signal_protocol_address *remote_address,
+        signal_context *global_context)
 {
     session_builder *result = 0;
 
@@ -39,7 +32,7 @@ int session_builder_create(session_builder **builder,
 
     result = malloc(sizeof(session_builder));
     if(!result) {
-        return AX_ERR_NOMEM;
+        return SG_ERR_NOMEM;
     }
     memset(result, 0, sizeof(session_builder));
 
@@ -51,43 +44,33 @@ int session_builder_create(session_builder **builder,
     return 0;
 }
 
-int session_builder_process_pre_key_whisper_message(session_builder *builder,
-        session_record *record, pre_key_whisper_message *message, uint32_t *unsigned_pre_key_id)
+int session_builder_process_pre_key_signal_message(session_builder *builder,
+        session_record *record, pre_key_signal_message *message, uint32_t *unsigned_pre_key_id)
 {
     int result = 0;
     int has_unsigned_pre_key_id_result = 0;
     uint32_t unsigned_pre_key_id_result = 0;
-    int message_version = pre_key_whisper_message_get_message_version(message);
-    ec_public_key *their_identity_key = pre_key_whisper_message_get_identity_key(message);
+    ec_public_key *their_identity_key = pre_key_signal_message_get_identity_key(message);
 
-    result = axolotl_identity_is_trusted_identity(builder->store,
-            builder->remote_address->name, builder->remote_address->name_len,
+    result = signal_protocol_identity_is_trusted_identity(builder->store,
+            builder->remote_address,
             their_identity_key);
     if(result < 0) {
         goto complete;
     }
     if(result == 0) {
-        result = AX_ERR_UNTRUSTED_IDENTITY;
+        result = SG_ERR_UNTRUSTED_IDENTITY;
         goto complete;
     }
 
-    if(message_version == 2) {
-        result = session_builder_process_pre_key_whisper_message_v2(builder, record, message, &unsigned_pre_key_id_result);
-    }
-    else if(message_version == 3) {
-        result = session_builder_process_pre_key_whisper_message_v3(builder, record, message, &unsigned_pre_key_id_result);
-    }
-    else {
-        axolotl_log(builder->global_context, AX_LOG_WARNING, "Unknown version: %d", message_version);
-        result = AX_ERR_INVALID_VERSION;
-    }
+    result = session_builder_process_pre_key_signal_message_v3(builder, record, message, &unsigned_pre_key_id_result);
     if(result < 0) {
         goto complete;
     }
     has_unsigned_pre_key_id_result = result;
 
-    result = axolotl_identity_save_identity(builder->store,
-            builder->remote_address->name, builder->remote_address->name_len,
+    result = signal_protocol_identity_save_identity(builder->store,
+            builder->remote_address,
             their_identity_key);
     if(result < 0) {
         goto complete;
@@ -102,195 +85,92 @@ complete:
     return result;
 }
 
-static int session_builder_process_pre_key_whisper_message_v2(session_builder *builder,
-        session_record *record, pre_key_whisper_message *message, uint32_t *unsigned_pre_key_id)
-{
-    int result = 0;
-    uint32_t unsigned_pre_key_id_result = 0;
-    session_pre_key *our_pre_key = 0;
-    ratchet_identity_key_pair *our_identity_key = 0;
-    bob_axolotl_parameters *parameters = 0;
-    uint32_t pre_key_id = 0;
-    int contains_session = 0;
-    session_state *state = 0;
-    int contains_key = 0;
-    uint32_t local_registration_id = 0;
-
-    if(!pre_key_whisper_message_has_pre_key_id(message)) {
-        axolotl_log(builder->global_context, AX_LOG_WARNING, "V2 message requires one time pre key ID!");
-        result = AX_ERR_INVALID_KEY_ID;
-        goto complete;
-    }
-
-    pre_key_id = pre_key_whisper_message_get_pre_key_id(message);
-
-    contains_key = axolotl_pre_key_contains_key(builder->store, pre_key_id);
-    if(contains_key < 0) {
-        result = contains_key;
-        goto complete;
-    }
-
-    contains_session = axolotl_session_contains_session(builder->store, builder->remote_address);
-    if(contains_session < 0) {
-        result = contains_session;
-        goto complete;
-    }
-
-    if(!contains_key && contains_session) {
-        axolotl_log(builder->global_context, AX_LOG_INFO, "We've already processed the prekey part of this V2 session, letting bundled message fall through...");
-        result = 0;
-        goto complete;
-    }
-
-    result = axolotl_pre_key_load_key(builder->store, &our_pre_key, pre_key_id);
-    if(result < 0) {
-        goto complete;
-    }
-
-    result = axolotl_identity_get_key_pair(builder->store, &our_identity_key);
-    if(result < 0) {
-        goto complete;
-    }
-
-    result = bob_axolotl_parameters_create(
-            &parameters,
-            our_identity_key,
-            session_pre_key_get_key_pair(our_pre_key),
-            0,
-            session_pre_key_get_key_pair(our_pre_key),
-            pre_key_whisper_message_get_identity_key(message),
-            pre_key_whisper_message_get_base_key(message));
-    if(result < 0) {
-        goto complete;
-    }
-
-    if(!session_record_is_fresh(record)) {
-        session_record_archive_current_state(record);
-    }
-
-    state = session_record_get_state(record);
-
-    result = ratcheting_session_bob_initialize(
-            state,
-            pre_key_whisper_message_get_message_version(message),
-            parameters, builder->global_context);
-    if(result < 0) {
-        goto complete;
-    }
-
-    result = axolotl_identity_get_local_registration_id(builder->store, &local_registration_id);
-    if(result < 0) {
-        goto complete;
-    }
-
-    session_state_set_local_registration_id(state, local_registration_id);
-    session_state_set_remote_registration_id(state,
-            pre_key_whisper_message_get_registration_id(message));
-    session_state_set_alice_base_key(state,
-            pre_key_whisper_message_get_base_key(message));;
-
-    if(pre_key_whisper_message_get_pre_key_id(message) != PRE_KEY_MEDIUM_MAX_VALUE) {
-        unsigned_pre_key_id_result = pre_key_whisper_message_get_pre_key_id(message);
-        result = 1;
-    }
-    else {
-        result = 0;
-    }
-
-complete:
-    AXOLOTL_UNREF(parameters);
-    AXOLOTL_UNREF(our_identity_key);
-    AXOLOTL_UNREF(our_pre_key);
-    if(result >= 0) {
-        *unsigned_pre_key_id = unsigned_pre_key_id_result;
-    }
-    return result;
-}
-
-static int session_builder_process_pre_key_whisper_message_v3(session_builder *builder,
-        session_record *record, pre_key_whisper_message *message, uint32_t *unsigned_pre_key_id)
+static int session_builder_process_pre_key_signal_message_v3(session_builder *builder,
+        session_record *record, pre_key_signal_message *message, uint32_t *unsigned_pre_key_id)
 {
     int result = 0;
     uint32_t unsigned_pre_key_id_result = 0;
     session_signed_pre_key *our_signed_pre_key = 0;
     ratchet_identity_key_pair *our_identity_key = 0;
-    bob_axolotl_parameters *parameters = 0;
+    bob_signal_protocol_parameters *parameters = 0;
     session_pre_key *session_our_one_time_pre_key = 0;
     ec_key_pair *our_one_time_pre_key = 0;
     session_state *state = 0;
     uint32_t local_registration_id = 0;
 
     int has_session_state = session_record_has_session_state(record,
-            pre_key_whisper_message_get_message_version(message),
-            pre_key_whisper_message_get_base_key(message));
+            pre_key_signal_message_get_message_version(message),
+            pre_key_signal_message_get_base_key(message));
     if(has_session_state) {
-        axolotl_log(builder->global_context, AX_LOG_INFO, "We've already setup a session for this V3 message, letting bundled message fall through...");
+        signal_log(builder->global_context, SG_LOG_INFO, "We've already setup a session for this V3 message, letting bundled message fall through...");
         result = 0;
         goto complete;
     }
 
-    result = axolotl_signed_pre_key_load_key(builder->store,
+    result = signal_protocol_signed_pre_key_load_key(builder->store,
             &our_signed_pre_key,
-            pre_key_whisper_message_get_signed_pre_key_id(message));
+            pre_key_signal_message_get_signed_pre_key_id(message));
     if(result < 0) {
         goto complete;
     }
 
-    result = axolotl_identity_get_key_pair(builder->store, &our_identity_key);
+    result = signal_protocol_identity_get_key_pair(builder->store, &our_identity_key);
     if(result < 0) {
         goto complete;
     }
 
-    if(pre_key_whisper_message_has_pre_key_id(message)) {
-        result = axolotl_pre_key_load_key(builder->store,
+    if(pre_key_signal_message_has_pre_key_id(message)) {
+        result = signal_protocol_pre_key_load_key(builder->store,
                 &session_our_one_time_pre_key,
-                pre_key_whisper_message_get_pre_key_id(message));
+                pre_key_signal_message_get_pre_key_id(message));
         if(result < 0) {
             goto complete;
         }
         our_one_time_pre_key = session_pre_key_get_key_pair(session_our_one_time_pre_key);
     }
 
-    result = bob_axolotl_parameters_create(
+    result = bob_signal_protocol_parameters_create(
             &parameters,
             our_identity_key,
             session_signed_pre_key_get_key_pair(our_signed_pre_key),
             our_one_time_pre_key,
             session_signed_pre_key_get_key_pair(our_signed_pre_key),
-            pre_key_whisper_message_get_identity_key(message),
-            pre_key_whisper_message_get_base_key(message));
+            pre_key_signal_message_get_identity_key(message),
+            pre_key_signal_message_get_base_key(message));
     if(result < 0) {
         goto complete;
     }
 
     if(!session_record_is_fresh(record)) {
-        session_record_archive_current_state(record);
+        result = session_record_archive_current_state(record);
+        if(result < 0) {
+            goto complete;
+        }
     }
 
     state = session_record_get_state(record);
 
     result = ratcheting_session_bob_initialize(
-            state,
-            pre_key_whisper_message_get_message_version(message),
-            parameters, builder->global_context);
+            state, parameters,
+            builder->global_context);
     if(result < 0) {
         goto complete;
     }
 
-    result = axolotl_identity_get_local_registration_id(builder->store, &local_registration_id);
+    result = signal_protocol_identity_get_local_registration_id(builder->store, &local_registration_id);
     if(result < 0) {
         goto complete;
     }
 
     session_state_set_local_registration_id(state, local_registration_id);
     session_state_set_remote_registration_id(state,
-            pre_key_whisper_message_get_registration_id(message));
+            pre_key_signal_message_get_registration_id(message));
     session_state_set_alice_base_key(state,
-            pre_key_whisper_message_get_base_key(message));;
+            pre_key_signal_message_get_base_key(message));;
 
-    if(pre_key_whisper_message_has_pre_key_id(message) &&
-            pre_key_whisper_message_get_pre_key_id(message) != PRE_KEY_MEDIUM_MAX_VALUE) {
-        unsigned_pre_key_id_result = pre_key_whisper_message_get_pre_key_id(message);
+    if(pre_key_signal_message_has_pre_key_id(message) &&
+            pre_key_signal_message_get_pre_key_id(message) != PRE_KEY_MEDIUM_MAX_VALUE) {
+        unsigned_pre_key_id_result = pre_key_signal_message_get_pre_key_id(message);
         result = 1;
     }
     else {
@@ -298,10 +178,10 @@ static int session_builder_process_pre_key_whisper_message_v3(session_builder *b
     }
 
 complete:
-    AXOLOTL_UNREF(parameters);
-    AXOLOTL_UNREF(our_identity_key);
-    AXOLOTL_UNREF(our_signed_pre_key);
-    AXOLOTL_UNREF(session_our_one_time_pre_key);
+    SIGNAL_UNREF(parameters);
+    SIGNAL_UNREF(our_identity_key);
+    SIGNAL_UNREF(our_signed_pre_key);
+    SIGNAL_UNREF(session_our_one_time_pre_key);
     if(result >= 0) {
         *unsigned_pre_key_id = unsigned_pre_key_id_result;
     }
@@ -314,10 +194,9 @@ int session_builder_process_pre_key_bundle(session_builder *builder, session_pre
     session_record *record = 0;
     ec_key_pair *our_base_key = 0;
     ratchet_identity_key_pair *our_identity_key = 0;
-    alice_axolotl_parameters *parameters = 0;
+    alice_signal_protocol_parameters *parameters = 0;
     ec_public_key *signed_pre_key = 0;
     ec_public_key *pre_key = 0;
-    int supports_v3 = 0;
     ec_public_key *their_identity_key = 0;
     ec_public_key *their_signed_pre_key = 0;
     ec_public_key *their_one_time_pre_key = 0;
@@ -329,16 +208,16 @@ int session_builder_process_pre_key_bundle(session_builder *builder, session_pre
     assert(builder);
     assert(builder->store);
     assert(bundle);
-    axolotl_lock(builder->global_context);
+    signal_lock(builder->global_context);
 
-    result = axolotl_identity_is_trusted_identity(builder->store,
-            builder->remote_address->name, builder->remote_address->name_len,
+    result = signal_protocol_identity_is_trusted_identity(builder->store,
+            builder->remote_address,
             session_pre_key_bundle_get_identity_key(bundle));
     if(result < 0) {
         goto complete;
     }
     if(result == 0) {
-        result = AX_ERR_UNTRUSTED_IDENTITY;
+        result = SG_ERR_UNTRUSTED_IDENTITY;
         goto complete;
     }
 
@@ -347,40 +226,38 @@ int session_builder_process_pre_key_bundle(session_builder *builder, session_pre
 
     if(signed_pre_key) {
         ec_public_key *identity_key = session_pre_key_bundle_get_identity_key(bundle);
-        axolotl_buffer *signature = session_pre_key_bundle_get_signed_pre_key_signature(bundle);
+        signal_buffer *signature = session_pre_key_bundle_get_signed_pre_key_signature(bundle);
 
-        axolotl_buffer *serialized_signed_pre_key = 0;
+        signal_buffer *serialized_signed_pre_key = 0;
         result = ec_public_key_serialize(&serialized_signed_pre_key, signed_pre_key);
         if(result < 0) {
             goto complete;
         }
 
         result = curve_verify_signature(identity_key,
-                axolotl_buffer_data(serialized_signed_pre_key),
-                axolotl_buffer_len(serialized_signed_pre_key),
-                axolotl_buffer_data(signature),
-                axolotl_buffer_len(signature));
+                signal_buffer_data(serialized_signed_pre_key),
+                signal_buffer_len(serialized_signed_pre_key),
+                signal_buffer_data(signature),
+                signal_buffer_len(signature));
 
-        axolotl_buffer_free(serialized_signed_pre_key);
+        signal_buffer_free(serialized_signed_pre_key);
 
         if(result == 0) {
-            axolotl_log(builder->global_context, AX_LOG_WARNING, "invalid signature on device key!");
-            result = AX_ERR_INVALID_KEY;
+            signal_log(builder->global_context, SG_LOG_WARNING, "invalid signature on device key!");
+            result = SG_ERR_INVALID_KEY;
         }
         if(result < 0) {
             goto complete;
         }
     }
 
-    if(!signed_pre_key && !pre_key) {
-        result = AX_ERR_INVALID_KEY;
-        axolotl_log(builder->global_context, AX_LOG_WARNING, "both signed and unsigned pre keys are absent!");
+    if(!signed_pre_key) {
+        result = SG_ERR_INVALID_KEY;
+        signal_log(builder->global_context, SG_LOG_WARNING, "no signed pre key!");
         goto complete;
     }
 
-    supports_v3 = (signed_pre_key != 0);
-
-    result = axolotl_session_load_session(builder->store, &record, builder->remote_address);
+    result = signal_protocol_session_load_session(builder->store, &record, builder->remote_address);
     if(result < 0) {
         goto complete;
     }
@@ -391,8 +268,7 @@ int session_builder_process_pre_key_bundle(session_builder *builder, session_pre
     }
 
     their_identity_key = session_pre_key_bundle_get_identity_key(bundle);
-    their_signed_pre_key = supports_v3 ? signed_pre_key : pre_key;
-
+    their_signed_pre_key = signed_pre_key;
     their_one_time_pre_key = pre_key;
 
     if(their_one_time_pre_key) {
@@ -400,31 +276,33 @@ int session_builder_process_pre_key_bundle(session_builder *builder, session_pre
         their_one_time_pre_key_id = session_pre_key_bundle_get_pre_key_id(bundle);
     }
 
-    result = axolotl_identity_get_key_pair(builder->store, &our_identity_key);
+    result = signal_protocol_identity_get_key_pair(builder->store, &our_identity_key);
     if(result < 0) {
         goto complete;
     }
 
-    result = alice_axolotl_parameters_create(&parameters,
+    result = alice_signal_protocol_parameters_create(&parameters,
             our_identity_key,
             our_base_key,
             their_identity_key,
             their_signed_pre_key,
-            supports_v3 ? their_one_time_pre_key : 0,
+            their_one_time_pre_key,
             their_signed_pre_key);
     if(result < 0) {
         goto complete;
     }
 
     if(!session_record_is_fresh(record)) {
-        session_record_archive_current_state(record);
+        result = session_record_archive_current_state(record);
+        if(result < 0) {
+            goto complete;
+        }
     }
 
     state = session_record_get_state(record);
 
     result = ratcheting_session_alice_initialize(
-            state,
-            supports_v3 ? 3 : 2, parameters,
+            state, parameters,
             builder->global_context);
     if(result < 0) {
         goto complete;
@@ -435,7 +313,7 @@ int session_builder_process_pre_key_bundle(session_builder *builder, session_pre
             session_pre_key_bundle_get_signed_pre_key_id(bundle),
             ec_key_pair_get_public(our_base_key));
 
-    result = axolotl_identity_get_local_registration_id(builder->store, &local_registration_id);
+    result = signal_protocol_identity_get_local_registration_id(builder->store, &local_registration_id);
     if(result < 0) {
         goto complete;
     }
@@ -445,417 +323,24 @@ int session_builder_process_pre_key_bundle(session_builder *builder, session_pre
             session_pre_key_bundle_get_registration_id(bundle));
     session_state_set_alice_base_key(state, ec_key_pair_get_public(our_base_key));
 
-    axolotl_session_store_session(builder->store, builder->remote_address, record);
-    axolotl_identity_save_identity(builder->store,
-            builder->remote_address->name, builder->remote_address->name_len,
-            their_identity_key);
-
-complete:
-    AXOLOTL_UNREF(record);
-    AXOLOTL_UNREF(our_base_key);
-    AXOLOTL_UNREF(our_identity_key);
-    AXOLOTL_UNREF(parameters);
-    axolotl_unlock(builder->global_context);
-    return result;
-}
-
-int session_builder_process_key_exchange_message(session_builder *builder, key_exchange_message *message, key_exchange_message **response_message)
-{
-    int result = 0;
-    key_exchange_message *result_response_message = 0;
-
-    assert(builder);
-    assert(builder->store);
-    axolotl_lock(builder->global_context);
-
-    result = axolotl_identity_is_trusted_identity(builder->store,
-            builder->remote_address->name, builder->remote_address->name_len,
-            key_exchange_message_get_identity_key(message));
-    if(result < 0) {
-        goto complete;
-    }
-    if(result == 0) {
-        result = AX_ERR_UNTRUSTED_IDENTITY;
-        goto complete;
-    }
-    result = 0;
-
-    if(key_exchange_message_is_initiate(message)) {
-        result = session_builder_process_initiate(builder, message, &result_response_message);
-    }
-    else {
-        result = session_builder_process_response(builder, message);
-    }
-
-complete:
-    if(result >= 0) {
-        *response_message = result_response_message;
-    }
-    else {
-        AXOLOTL_UNREF(result_response_message);
-    }
-    axolotl_unlock(builder->global_context);
-    return result;
-}
-
-static int session_builder_process_initiate(session_builder *builder, key_exchange_message *message, key_exchange_message **response_message)
-{
-    int result = 0;
-    key_exchange_message *result_response_message = 0;
-
-    uint32_t flags = KEY_EXCHANGE_RESPONSE_FLAG;
-    session_record *record = 0;
-    session_state *state = 0;
-    ratchet_identity_key_pair *identity_key_pair = 0;
-    ec_key_pair *our_base_key = 0;
-    ec_key_pair *our_ratchet_key = 0;
-    symmetric_axolotl_parameters *parameters = 0;
-    ratchet_identity_key_pair *parameters_identity_key = 0;
-    ec_key_pair *parameters_base_key = 0;
-    axolotl_buffer *parameters_public_base_key_serialized = 0;
-    ec_key_pair *parameters_ratchet_key = 0;
-    axolotl_buffer *base_key_signature = 0;
-
-    result = axolotl_session_load_session(builder->store, &record, builder->remote_address);
+    result = signal_protocol_session_store_session(builder->store, builder->remote_address, record);
     if(result < 0) {
         goto complete;
     }
 
-    if(key_exchange_message_get_version(message) >= 3) {
-        ec_public_key *message_identity_key = key_exchange_message_get_identity_key(message);
-        ec_public_key *message_base_key = key_exchange_message_get_base_key(message);
-        axolotl_buffer *message_base_key_serialized = 0;
-        uint8_t *message_base_key_signature = 0;
-
-        ec_public_key_serialize(&message_base_key_serialized, message_base_key);
-
-        message_base_key_signature = key_exchange_message_get_base_key_signature(message);
-
-        result = curve_verify_signature(message_identity_key,
-                axolotl_buffer_data(message_base_key_serialized),
-                axolotl_buffer_len(message_base_key_serialized),
-                message_base_key_signature, CURVE_SIGNATURE_LEN);
-        axolotl_buffer_free(message_base_key_serialized);
-        if(result < 0) {
-            goto complete;
-        }
-        if(result != 1) {
-            axolotl_log(builder->global_context, AX_LOG_WARNING, "Bad signature!");
-            result = AX_ERR_INVALID_KEY;
-            goto complete;
-        }
-    }
-
-    state = session_record_get_state(record);
-    if(!session_state_has_pending_key_exchange(state)) {
-        result = axolotl_identity_get_key_pair(builder->store, &identity_key_pair);
-        if(result < 0) {
-            goto complete;
-        }
-
-        result = curve_generate_key_pair(builder->global_context, &our_base_key);
-        if(result < 0) {
-            goto complete;
-        }
-
-        result = curve_generate_key_pair(builder->global_context, &our_ratchet_key);
-        if(result < 0) {
-            goto complete;
-        }
-
-        result = symmetric_axolotl_parameters_create(
-                &parameters,
-                identity_key_pair,
-                our_base_key,
-                our_ratchet_key,
-                key_exchange_message_get_base_key(message),
-                key_exchange_message_get_ratchet_key(message),
-                key_exchange_message_get_identity_key(message));
-        if(result < 0) {
-            goto complete;
-        }
-    }
-    else {
-        result = symmetric_axolotl_parameters_create(
-                &parameters,
-                session_state_get_pending_key_exchange_identity_key(state),
-                session_state_get_pending_key_exchange_base_key(state),
-                session_state_get_pending_key_exchange_ratchet_key(state),
-                key_exchange_message_get_base_key(message),
-                key_exchange_message_get_ratchet_key(message),
-                key_exchange_message_get_identity_key(message));
-        if(result < 0) {
-            goto complete;
-        }
-
-        flags |= KEY_EXCHANGE_SIMULTAENOUS_INITIATE_FLAG;
-    }
-
-    if(!session_record_is_fresh(record)) {
-        session_record_archive_current_state(record);
-    }
-
-    state = session_record_get_state(record);
-    result = ratcheting_session_symmetric_initialize(state,
-            MIN(key_exchange_message_get_max_version(message), (uint32_t)CIPHERTEXT_CURRENT_VERSION),
-            parameters, builder->global_context);
-    if(result < 0) {
-        goto complete;
-    }
-
-    result = axolotl_session_store_session(builder->store, builder->remote_address, record);
-    if(result < 0) {
-        goto complete;
-    }
-
-    result = axolotl_identity_save_identity(builder->store,
-            builder->remote_address->name, builder->remote_address->name_len,
-            key_exchange_message_get_identity_key(message));
-    if(result < 0) {
-        goto complete;
-    }
-
-    parameters_identity_key = symmetric_axolotl_parameters_get_our_identity_key(parameters);
-    parameters_base_key = symmetric_axolotl_parameters_get_our_base_key(parameters);
-    parameters_ratchet_key = symmetric_axolotl_parameters_get_our_ratchet_key(parameters);
-
-    result = ec_public_key_serialize(&parameters_public_base_key_serialized,
-            ec_key_pair_get_public(parameters_base_key));
-    if(result < 0) {
-        goto complete;
-    }
-
-    result = curve_calculate_signature(builder->global_context,
-            &base_key_signature,
-            ratchet_identity_key_pair_get_private(parameters_identity_key),
-            axolotl_buffer_data(parameters_public_base_key_serialized),
-            axolotl_buffer_len(parameters_public_base_key_serialized));
-    if(result < 0) {
-        goto complete;
-    }
-
-    result = key_exchange_message_create(&result_response_message,
-            session_state_get_session_version(state),
-            key_exchange_message_get_sequence(message),
-            flags,
-            ec_key_pair_get_public(parameters_base_key),
-            axolotl_buffer_data(base_key_signature),
-            ec_key_pair_get_public(parameters_ratchet_key),
-            ratchet_identity_key_pair_get_public(parameters_identity_key));
-
-complete:
-    axolotl_buffer_free(parameters_public_base_key_serialized);
-    axolotl_buffer_free(base_key_signature);
-    AXOLOTL_UNREF(our_base_key);
-    AXOLOTL_UNREF(our_ratchet_key);
-    AXOLOTL_UNREF(identity_key_pair);
-    AXOLOTL_UNREF(parameters);
-    AXOLOTL_UNREF(record);
-    if(result >= 0) {
-        *response_message = result_response_message;
-    }
-    else {
-        AXOLOTL_UNREF(result_response_message);
-    }
-    return result;
-}
-
-static int session_builder_process_response(session_builder *builder, key_exchange_message *message)
-{
-    int result = 0;
-    session_record *record = 0;
-    session_state *state = 0;
-    int has_pending_key_exchange = 0;
-    int is_simultaneous_initiate_response = 0;
-    symmetric_axolotl_parameters *parameters = 0;
-
-    result = axolotl_session_load_session(builder->store, &record, builder->remote_address);
-    if(result < 0) {
-        goto complete;
-    }
-
-    state = session_record_get_state(record);
-    has_pending_key_exchange = session_state_has_pending_key_exchange(state);
-    is_simultaneous_initiate_response = key_exchange_message_is_response_for_simultaneous_initiate(message);
-
-    if(!has_pending_key_exchange ||
-            session_state_get_pending_key_exchange_sequence(state) != key_exchange_message_get_sequence(message)) {
-        axolotl_log(builder->global_context, AX_LOG_INFO, "No matching sequence for response. Is simultaneous initiate response: %d", is_simultaneous_initiate_response);
-        if(!is_simultaneous_initiate_response) {
-            result = AX_ERR_STALE_KEY_EXCHANGE;
-            goto complete;
-        }
-        else  {
-            result = AX_SUCCESS;
-            goto complete;
-        }
-    }
-
-    result = symmetric_axolotl_parameters_create(
-            &parameters,
-            session_state_get_pending_key_exchange_identity_key(state),
-            session_state_get_pending_key_exchange_base_key(state),
-            session_state_get_pending_key_exchange_ratchet_key(state),
-            key_exchange_message_get_base_key(message),
-            key_exchange_message_get_ratchet_key(message),
-            key_exchange_message_get_identity_key(message));
-    if(result < 0) {
-        goto complete;
-    }
-
-    if(!session_record_is_fresh(record)) {
-        session_record_archive_current_state(record);
-    }
-
-    state = session_record_get_state(record);
-    result = ratcheting_session_symmetric_initialize(state,
-            MIN(key_exchange_message_get_max_version(message), (uint32_t)CIPHERTEXT_CURRENT_VERSION),
-            parameters, builder->global_context);
-    if(result < 0) {
-        goto complete;
-    }
-
-    result = axolotl_session_store_session(builder->store, builder->remote_address, record);
-    if(result < 0) {
-        goto complete;
-    }
-
-    if(session_state_get_session_version(state) >= 3) {
-        ec_public_key *message_identity_key = key_exchange_message_get_identity_key(message);
-        ec_public_key *message_base_key = key_exchange_message_get_base_key(message);
-        axolotl_buffer *message_base_key_serialized = 0;
-        uint8_t *message_base_key_signature = 0;
-
-        ec_public_key_serialize(&message_base_key_serialized, message_base_key);
-
-        message_base_key_signature = key_exchange_message_get_base_key_signature(message);
-
-        result = curve_verify_signature(message_identity_key,
-                axolotl_buffer_data(message_base_key_serialized),
-                axolotl_buffer_len(message_base_key_serialized),
-                message_base_key_signature, CURVE_SIGNATURE_LEN);
-        axolotl_buffer_free(message_base_key_serialized);
-        if(result < 0) {
-            goto complete;
-        }
-        if(result != 1) {
-            axolotl_log(builder->global_context, AX_LOG_WARNING, "Base key signature doesn't match!");
-            result = AX_ERR_INVALID_KEY;
-            goto complete;
-        }
-    }
-
-    result = axolotl_session_store_session(builder->store, builder->remote_address, record);
-    if(result < 0) {
-        goto complete;
-    }
-
-    result = axolotl_identity_save_identity(builder->store,
-            builder->remote_address->name, builder->remote_address->name_len,
-            key_exchange_message_get_identity_key(message));
-    if(result < 0) {
-        goto complete;
-    }
-
-complete:
-    AXOLOTL_UNREF(parameters);
-    AXOLOTL_UNREF(record);
-    return result;
-}
-
-int session_builder_process(session_builder *builder, key_exchange_message **message)
-{
-    int result = 0;
-    key_exchange_message *result_message = 0;
-    int random_value = 0;
-    uint32_t sequence = 0;
-    uint32_t flags = KEY_EXCHANGE_INITIATE_FLAG;
-    ec_key_pair *base_key = 0;
-    ec_key_pair *ratchet_key = 0;
-    ratchet_identity_key_pair *identity_key = 0;
-    axolotl_buffer *base_key_public_serialized = 0;
-    axolotl_buffer *base_key_signature = 0;
-    session_record *record = 0;
-    session_state *state = 0;
-
-    assert(builder);
-    assert(builder->store);
-    axolotl_lock(builder->global_context);
-
-    result = axolotl_key_helper_get_random_sequence(&random_value, 65534, builder->global_context);
-    if(result < 0) {
-        goto complete;
-    }
-    sequence = ((uint32_t)random_value) + 1;
-
-    result = curve_generate_key_pair(builder->global_context, &base_key);
-    if(result < 0) {
-        goto complete;
-    }
-
-    result = curve_generate_key_pair(builder->global_context, &ratchet_key);
-    if(result < 0) {
-        goto complete;
-    }
-
-    result = axolotl_identity_get_key_pair(builder->store, &identity_key);
-    if(result < 0) {
-        goto complete;
-    }
-
-    result = ec_public_key_serialize(&base_key_public_serialized, ec_key_pair_get_public(base_key));
-    if(result < 0) {
-        goto complete;
-    }
-
-    result = curve_calculate_signature(builder->global_context, &base_key_signature,
-            ratchet_identity_key_pair_get_private(identity_key),
-            axolotl_buffer_data(base_key_public_serialized),
-            axolotl_buffer_len(base_key_public_serialized));
-    if(result < 0) {
-        goto complete;
-    }
-
-    if(axolotl_buffer_len(base_key_signature) != CURVE_SIGNATURE_LEN) {
-        result = AX_ERR_UNKNOWN;
-        goto complete;
-    }
-
-    result = axolotl_session_load_session(builder->store, &record, builder->remote_address);
-    if(result < 0) {
-        goto complete;
-    }
-
-    state = session_record_get_state(record);
-    session_state_set_pending_key_exchange(state, sequence, base_key, ratchet_key, identity_key);
-
-    result = axolotl_session_store_session(builder->store, builder->remote_address, record);
+    result = signal_protocol_identity_save_identity(builder->store,
+            builder->remote_address,
+            their_identity_key);
     if(result < 0) {
         goto complete;
     }
 
-    result = key_exchange_message_create(&result_message,
-            2, sequence, flags,
-            ec_key_pair_get_public(base_key),
-            axolotl_buffer_data(base_key_signature),
-            ec_key_pair_get_public(ratchet_key),
-            ratchet_identity_key_pair_get_public(identity_key));
-
 complete:
-    AXOLOTL_UNREF(record);
-    axolotl_buffer_free(base_key_signature);
-    axolotl_buffer_free(base_key_public_serialized);
-    AXOLOTL_UNREF(identity_key);
-    AXOLOTL_UNREF(ratchet_key);
-    AXOLOTL_UNREF(base_key);
-    if(result >= 0) {
-        *message = result_message;
-    }
-    else {
-        result = AX_ERR_INVALID_KEY;
-        AXOLOTL_UNREF(result_message);
-    }
-    axolotl_unlock(builder->global_context);
+    SIGNAL_UNREF(record);
+    SIGNAL_UNREF(our_base_key);
+    SIGNAL_UNREF(our_identity_key);
+    SIGNAL_UNREF(parameters);
+    signal_unlock(builder->global_context);
     return result;
 }