diff --git a/Makefile b/Makefile
index ba848c9..47ce820 100644
--- a/Makefile
+++ b/Makefile
@@ -13,7 +13,7 @@ LINK_FLAGS=${LDFLAGS} ${LOCAL_LDFLAGS}
 HEADERS= ${srcdir}/constants.h  ${srcdir}/include.h  ${srcdir}/interface.h  ${srcdir}/LICENSE.h  ${srcdir}/loop.h  ${srcdir}/mtproto-client.h  ${srcdir}/mtproto-common.h  ${srcdir}/net.h  ${srcdir}/no-preview.h  ${srcdir}/queries.h  ${srcdir}/structures.h  ${srcdir}/telegram.h  ${srcdir}/tree.h ${srcdir}/config.h ${srcdir}/binlog.h
 INCLUDE=-I. -I${srcdir}
 CC=gcc
-OBJECTS=main.o loop.o interface.o net.o mtproto-common.o mtproto-client.o queries.o structures.o binlog.o
+OBJECTS=main.o loop.o interface.o net.o mtproto-common.o mtproto-client.o queries.o structures.o binlog.o tools.o
 
 .SUFFIXES:
 
diff --git a/Makefile.in b/Makefile.in
index 7c6589d..7898905 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -13,7 +13,7 @@ LINK_FLAGS=${LDFLAGS} ${LOCAL_LDFLAGS}
 HEADERS= ${srcdir}/constants.h  ${srcdir}/include.h  ${srcdir}/interface.h  ${srcdir}/LICENSE.h  ${srcdir}/loop.h  ${srcdir}/mtproto-client.h  ${srcdir}/mtproto-common.h  ${srcdir}/net.h  ${srcdir}/no-preview.h  ${srcdir}/queries.h  ${srcdir}/structures.h  ${srcdir}/telegram.h  ${srcdir}/tree.h ${srcdir}/config.h ${srcdir}/binlog.h
 INCLUDE=-I. -I${srcdir}
 CC=@CC@
-OBJECTS=main.o loop.o interface.o net.o mtproto-common.o mtproto-client.o queries.o structures.o binlog.o
+OBJECTS=main.o loop.o interface.o net.o mtproto-common.o mtproto-client.o queries.o structures.o binlog.o tools.o
 
 .SUFFIXES:
 
diff --git a/binlog.c b/binlog.c
index a71b4a7..0414fa1 100644
--- a/binlog.c
+++ b/binlog.c
@@ -183,7 +183,7 @@ void replay_log_event (void) {
       memcpy (U->key, rptr, 256);
       rptr += 64;
       if (!U->g_key) {
-        U->g_key = malloc (256);
+        U->g_key = talloc (256);
       }
       memcpy (U->g_key, rptr, 256);
       rptr += 64;
@@ -196,8 +196,7 @@ void replay_log_event (void) {
       struct secret_chat *U = (void *)user_chat_get (id);
       assert (!U || !(U->flags & FLAG_CREATED));
       if (!U) {
-        U = malloc (sizeof (peer_t));
-        memset (U, 0, sizeof (peer_t));
+        U = talloc0 (sizeof (peer_t));
         U->id = id;
         insert_encrypted_chat ((void *)U);
       }
@@ -223,8 +222,7 @@ void replay_log_event (void) {
       peer_id_t id = MK_ENCR_CHAT (*(rptr ++));
       struct secret_chat *U = (void *)user_chat_get (id);
       if (!U) {
-        U = malloc (sizeof (peer_t));
-        memset (U, 0, sizeof (peer_t));
+        U = talloc0 (sizeof (peer_t));
         U->id = id;
         insert_encrypted_chat ((void *)U);
       }
@@ -252,8 +250,7 @@ void replay_log_event (void) {
       peer_id_t id = MK_ENCR_CHAT (*(rptr ++));
       struct secret_chat *U = (void *)user_chat_get (id);
       if (!U) {
-        U = malloc (sizeof (peer_t));
-        memset (U, 0, sizeof (peer_t));
+        U = talloc0 (sizeof (peer_t));
         U->id = id;
         insert_encrypted_chat ((void *)U);
       }
@@ -291,8 +288,7 @@ void replay_log_event (void) {
       peer_id_t id = MK_USER (fetch_int ());
       peer_t *_U = user_chat_get (id);
       if (!_U) {
-        _U = malloc (sizeof (*_U));
-        memset (_U, 0, sizeof (*_U));
+        _U = talloc0 (sizeof (*_U));
         _U->id = id;
         insert_user (_U);
       } else {
@@ -418,8 +414,7 @@ void replay_log_event (void) {
       peer_id_t id = MK_ENCR_CHAT (*(rptr ++));
       peer_t *_U = user_chat_get (id);
       if (!_U) {
-        _U = malloc (sizeof (*_U));
-        memset (_U, 0, sizeof (*_U));
+        _U = talloc0 (sizeof (*_U));
         _U->id = id;
         insert_encrypted_chat (_U);
       } else {
@@ -440,8 +435,8 @@ void replay_log_event (void) {
         sprintf (buf, "user#%d", U->user_id);
         U->print_name = create_print_name (id, "!", buf, 0, 0);
       }
-      U->g_key = malloc (256);
-      U->nonce = malloc (256);
+      U->g_key = talloc (256);
+      U->nonce = talloc (256);
       memcpy (U->g_key, rptr, 256);
       rptr += 64;
       memcpy (U->nonce, rptr, 256);
@@ -487,10 +482,10 @@ void replay_log_event (void) {
       assert (_U);
       struct secret_chat *U = &_U->encr_chat;
       if (!U->g_key) {
-        U->g_key = malloc (256);
+        U->g_key = talloc (256);
       }
       if (!U->nonce) {
-        U->nonce = malloc (256);
+        U->nonce = talloc (256);
       }
       memcpy (U->g_key, rptr, 256);
       rptr += 64;
@@ -522,7 +517,7 @@ void replay_log_event (void) {
     {
       if (encr_prime) { free (encr_prime); }
       encr_root = *(rptr ++);
-      encr_prime = malloc (256);
+      encr_prime = talloc (256);
       memcpy (encr_prime, rptr, 256);
       rptr += 64;
       encr_param_version = *(rptr ++);
@@ -532,8 +527,7 @@ void replay_log_event (void) {
   case CODE_binlog_encr_chat_init:
     rptr ++;
     {
-      peer_t *P = malloc (sizeof (*P));
-      memset (P, 0, sizeof (*P));
+      peer_t *P = talloc0 (sizeof (*P));
       P->id = MK_ENCR_CHAT (*(rptr ++));
       assert (!user_chat_get (P->id));
       P->encr_chat.user_id = *(rptr ++);
@@ -544,7 +538,7 @@ void replay_log_event (void) {
       P->print_name = create_print_name (P->id, "!", Us->user.first_name, Us->user.last_name, 0);
       memcpy (P->encr_chat.key, rptr, 256);
       rptr += 64;
-      P->encr_chat.g_key = malloc (256);
+      P->encr_chat.g_key = talloc (256);
       memcpy (P->encr_chat.g_key, rptr, 256);
       rptr += 64;
       P->flags |= FLAG_CREATED;
@@ -572,8 +566,7 @@ void replay_log_event (void) {
       peer_id_t id = MK_CHAT (fetch_int ());
       peer_t *_C = user_chat_get (id);
       if (!_C) {
-        _C = malloc (sizeof (*_C));
-        memset (_C, 0, sizeof (*_C));
+        _C = talloc0 (sizeof (*_C));
         _C->id = id;
         insert_chat (_C);
       } else {
@@ -655,7 +648,7 @@ void replay_log_event (void) {
       C->chat.user_list_version = *(rptr ++);
       C->chat.user_list_size = *(rptr ++);
       if (C->chat.user_list) { free (C->chat.user_list); }
-      C->chat.user_list = malloc (12 * C->chat.user_list_size);
+      C->chat.user_list = talloc (12 * C->chat.user_list_size);
       memcpy (C->chat.user_list, rptr, 12 * C->chat.user_list_size);
       rptr += 3 * C->chat.user_list_size;
     };
@@ -738,8 +731,7 @@ void replay_log_event (void) {
       }
       struct message *M = message_get (id);
       if (!M) {
-        M = malloc (sizeof (*M));
-        memset (M, 0, sizeof (*M));
+        M = talloc0 (sizeof (*M));
         M->id = id;
         message_insert_tree (M);
         messages_allocated ++;
@@ -756,7 +748,7 @@ void replay_log_event (void) {
       M->date = fetch_int ();
       
       int l = prefetch_strlen ();
-      M->message = malloc (l + 1);
+      M->message = talloc (l + 1);
       memcpy (M->message, fetch_str (l), l);
       M->message[l] = 0;
       M->message_len = l;
@@ -783,8 +775,7 @@ void replay_log_event (void) {
       int id = fetch_int ();
       struct message *M = message_get (id);
       if (!M) {
-        M = malloc (sizeof (*M));
-        memset (M, 0, sizeof (*M));
+        M = talloc0 (sizeof (*M));
         M->id = id;
         message_insert_tree (M);
         messages_allocated ++;
@@ -800,7 +791,7 @@ void replay_log_event (void) {
       M->fwd_date = fetch_int ();
       
       int l = prefetch_strlen ();
-      M->message = malloc (l + 1);
+      M->message = talloc (l + 1);
       memcpy (M->message, fetch_str (l), l);
       M->message[l] = 0;
       M->message_len = l;
@@ -819,8 +810,7 @@ void replay_log_event (void) {
       int id = fetch_int ();
       struct message *M = message_get (id);
       if (!M) {
-        M = malloc (sizeof (*M));
-        memset (M, 0, sizeof (*M));
+        M = talloc0 (sizeof (*M));
         M->id = id;
         message_insert_tree (M);
         messages_allocated ++;
@@ -834,7 +824,7 @@ void replay_log_event (void) {
       M->date = fetch_int ();
       
       int l = prefetch_strlen ();
-      M->message = malloc (l + 1);
+      M->message = talloc (l + 1);
       memcpy (M->message, fetch_str (l), l);
       M->message[l] = 0;
       M->message_len = l;
@@ -853,8 +843,7 @@ void replay_log_event (void) {
       long long id = fetch_long ();
       struct message *M = message_get (id);
       if (!M) {
-        M = malloc (sizeof (*M));
-        memset (M, 0, sizeof (*M));
+        M = talloc0 (sizeof (*M));
         M->id = id;
         message_insert_tree (M);
         messages_allocated ++;
@@ -868,7 +857,7 @@ void replay_log_event (void) {
       M->date = fetch_int ();
       
       int l = prefetch_strlen ();
-      M->message = malloc (l + 1);
+      M->message = talloc (l + 1);
       memcpy (M->message, fetch_str (l), l);
       M->message[l] = 0;
       M->message_len = l;
@@ -889,8 +878,7 @@ void replay_log_event (void) {
       int id = fetch_int ();
       struct message *M = message_get (id);
       if (!M) {
-        M = malloc (sizeof (*M));
-        memset (M, 0, sizeof (*M));
+        M = talloc0 (sizeof (*M));
         M->id = id;
         message_insert_tree (M);
         messages_allocated ++;
@@ -906,7 +894,7 @@ void replay_log_event (void) {
       M->fwd_date = fetch_int ();
       
       int l = prefetch_strlen ();
-      M->message = malloc (l + 1);
+      M->message = talloc (l + 1);
       memcpy (M->message, fetch_str (l), l);
       M->message[l] = 0;
       M->message_len = l;
@@ -925,8 +913,7 @@ void replay_log_event (void) {
       int id = fetch_int ();
       struct message *M = message_get (id);
       if (!M) {
-        M = malloc (sizeof (*M));
-        memset (M, 0, sizeof (*M));
+        M = talloc0 (sizeof (*M));
         M->id = id;
         message_insert_tree (M);
         messages_allocated ++;
@@ -954,8 +941,7 @@ void replay_log_event (void) {
       long long id = fetch_long ();
       struct message *M = message_get (id);
       if (!M) {
-        M = malloc (sizeof (*M));
-        memset (M, 0, sizeof (*M));
+        M = talloc0 (sizeof (*M));
         M->id = id;
         message_insert_tree (M);
         messages_allocated ++;
@@ -984,8 +970,7 @@ void replay_log_event (void) {
       int id = fetch_int ();
       struct message *M = message_get (id);
       if (!M) {
-        M = malloc (sizeof (*M));
-        memset (M, 0, sizeof (*M));
+        M = talloc0 (sizeof (*M));
         M->id = id;
         message_insert_tree (M);
         messages_allocated ++;
diff --git a/interface.c b/interface.c
index a535e82..65a5f56 100644
--- a/interface.c
+++ b/interface.c
@@ -413,7 +413,7 @@ int complete_user_list (int index, const char *text, int len, char **R) {
     index ++;
   }
   if (index < peer_num) {
-    *R = strdup (Peers[index]->print_name);
+    *R = tstrdup (Peers[index]->print_name);
     return index;
   } else {
     return -1;
@@ -426,7 +426,7 @@ int complete_chat_list (int index, const char *text, int len, char **R) {
     index ++;
   }
   if (index < peer_num) {
-    *R = strdup (Peers[index]->print_name);
+    *R = tstrdup (Peers[index]->print_name);
     return index;
   } else {
     return -1;
@@ -439,7 +439,7 @@ int complete_encr_chat_list (int index, const char *text, int len, char **R) {
     index ++;
   }
   if (index < peer_num) {
-    *R = strdup (Peers[index]->print_name);
+    *R = tstrdup (Peers[index]->print_name);
     return index;
   } else {
     return -1;
@@ -452,7 +452,7 @@ int complete_user_chat_list (int index, const char *text, int len, char **R) {
     index ++;
   }
   if (index < peer_num) {
-    *R = strdup (Peers[index]->print_name);
+    *R = tstrdup (Peers[index]->print_name);
     return index;
   } else {
     return -1;
@@ -465,7 +465,7 @@ int complete_string_list (char **list, int index, const char *text, int len, cha
     index ++;
   }
   if (list[index]) {
-    *R = strdup (list[index]);
+    *R = tstrdup (list[index]);
     return index;
   } else {
     *R = 0;
@@ -1100,7 +1100,7 @@ void print_start (void) {
     rl_replace_line("", 0);
 #else
     assert (rl_end >= 0);
-    saved_line = malloc (rl_end + 1);
+    saved_line = talloc (rl_end + 1);
     memcpy (saved_line, rl_line_buffer, rl_end + 1);
     rl_line_buffer[0] = 0;
     set_prompt ("");
diff --git a/loop.c b/loop.c
index f4b5fef..71c4746 100644
--- a/loop.c
+++ b/loop.c
@@ -200,7 +200,7 @@ void read_dc (int auth_file_fd, int id, unsigned ver) {
   int l = 0;
   assert (read (auth_file_fd, &l, 4) == 4);
   assert (l >= 0);
-  char *ip = malloc (l + 1);
+  char *ip = talloc (l + 1);
   assert (read (auth_file_fd, ip, l) == l);
   ip[l] = 0;
   struct dc *DC = alloc_dc (id, ip, port);
@@ -218,8 +218,7 @@ void read_dc (int auth_file_fd, int id, unsigned ver) {
 }
 
 void empty_auth_file (void) {
-  struct dc *DC = alloc_dc (1, strdup (test_dc ? TG_SERVER_TEST : TG_SERVER), 443);
-  assert (DC);
+  alloc_dc (1, tstrdup (test_dc ? TG_SERVER_TEST : TG_SERVER), 443);
   dc_working_num = 1;
   auth_state = 0;
   write_auth_file ();
@@ -338,8 +337,7 @@ void read_secret_chat_file (void) {
   assert (read (fd, &cc, 4) == 4);
   int i;
   for (i = 0; i < cc; i++) {
-    peer_t *P = malloc (sizeof (*P));
-    memset (P, 0, sizeof (*P));
+    peer_t *P = talloc0 (sizeof (*P));
     struct secret_chat *E = &P->encr_chat;
     int t;
     assert (read (fd, &t, 4) == 4);
@@ -347,7 +345,7 @@ void read_secret_chat_file (void) {
     assert (read (fd, &P->flags, 4) == 4);
     assert (read (fd, &t, 4) == 4);
     assert (t > 0);
-    P->print_name = malloc (t + 1);
+    P->print_name = talloc (t + 1);
     assert (read (fd, P->print_name, t) == t);
     P->print_name[t] = 0;
 
@@ -358,9 +356,9 @@ void read_secret_chat_file (void) {
     assert (read (fd, &E->access_hash, 8) == 8);
 
     if (E->state != sc_waiting) {
-      E->g_key = malloc (256);
+      E->g_key = talloc (256);
       assert (read (fd, E->g_key, 256) == 256);
-      E->nonce = malloc (256);
+      E->nonce = talloc (256);
       assert (read (fd, E->nonce, 256) == 256);
     }
     assert (read (fd, E->key, 256) == 256);
@@ -371,7 +369,7 @@ void read_secret_chat_file (void) {
     assert (read (fd, &encr_root, 4) == 4);
     if (encr_root) {
       assert (read (fd, &encr_param_version, 4) == 4);
-      encr_prime = malloc (256);
+      encr_prime = talloc (256);
       assert (read (fd, encr_prime, 256) == 256);
     }
   }
diff --git a/main.c b/main.c
index f0cd56d..4c6841f 100644
--- a/main.c
+++ b/main.c
@@ -45,6 +45,7 @@
 #include "loop.h"
 #include "mtproto-client.h"
 #include "interface.h"
+#include "tools.h"
 
 #define PROGNAME "telegram-client"
 #define VERSION "0.01"
@@ -84,7 +85,7 @@ void set_default_username (const char *s) {
   if (default_username) { 
     free (default_username);
   }
-  default_username = strdup (s);
+  default_username = tstrdup (s);
 }
 
 
@@ -236,13 +237,13 @@ void parse_config_val (config_t *conf, char **s, char *param_name, const char *d
     if (path) {
       assert (asprintf (s, "%s/%s", path, r) >= 0);
     } else {
-      *s = strdup (r);
+      *s = tstrdup (r);
     }
   } else {
     if (path) {
       assert (asprintf (s, "%s/%s", path, default_name) >= 0);
     } else {
-      *s  = strdup (default_name);
+      *s  = tstrdup (default_name);
     }
   }
 }
@@ -338,7 +339,7 @@ void args_parse (int argc, char **argv) {
       set_default_username (optarg);
       break;
     case 'k':
-      rsa_public_key_name = strdup (optarg);
+      rsa_public_key_name = tstrdup (optarg);
       break;
     case 'v':
       verbosity ++;
@@ -347,10 +348,10 @@ void args_parse (int argc, char **argv) {
       msg_num_mode ++;
       break;
     case 'c':
-      config_filename = strdup (optarg);
+      config_filename = tstrdup (optarg);
       break;
     case 'p':
-      prefix = strdup (optarg);
+      prefix = tstrdup (optarg);
       assert (strlen (prefix) <= 100);
       break;
     case 'l':
@@ -369,7 +370,7 @@ void args_parse (int argc, char **argv) {
       if (log_net_file) { 
         usage ();
       }
-      log_net_file = strdup (optarg);
+      log_net_file = tstrdup (optarg);
       log_net_f = fopen (log_net_file, "a");
       assert (log_net_f);
       break;
diff --git a/mtproto-client.c b/mtproto-client.c
index 54fde7a..3fc865c 100644
--- a/mtproto-client.c
+++ b/mtproto-client.c
@@ -431,9 +431,9 @@ int check_DH_params (BIGNUM *p, int g) {
   BN_init (&t);
 
   BN_init (&dh_g);
-  BN_set_word (&dh_g, 4 * g);
+  ensure (BN_set_word (&dh_g, 4 * g));
 
-  BN_mod (&t, p, &dh_g, BN_ctx);
+  ensure (BN_mod (&t, p, &dh_g, BN_ctx));
   int x = BN_get_word (&t);
   assert (x >= 0 && x < 4 * g);
 
@@ -463,8 +463,8 @@ int check_DH_params (BIGNUM *p, int g) {
 
   BIGNUM b;
   BN_init (&b);
-  BN_set_word (&b, 2);
-  BN_div (&t, 0, p, &b, BN_ctx);
+  ensure (BN_set_word (&b, 2));
+  ensure (BN_div (&t, 0, p, &b, BN_ctx));
   if (!BN_is_prime (&t, BN_prime_checks, 0, BN_ctx, 0)) { return -1; }
   BN_clear (&b);
   BN_clear (&t);
@@ -571,19 +571,20 @@ int process_dh_answer (struct connection *c, char *packet, int len) {
   out_long (0LL);
   
   BN_init (&dh_g);
-  BN_set_word (&dh_g, g);
+  ensure (BN_set_word (&dh_g, g));
 
   secure_random (s_power, 256);
-  BIGNUM *dh_power = BN_new ();
-  assert (BN_bin2bn ((unsigned char *)s_power, 256, dh_power) == dh_power);
+  BIGNUM *dh_power = BN_bin2bn ((unsigned char *)s_power, 256, 0);
+  ensure_ptr (dh_power);
 
   BIGNUM *y = BN_new ();
-  assert (BN_mod_exp (y, &dh_g, dh_power, &dh_prime, BN_ctx) == 1);
+  ensure_ptr (y);
+  ensure (BN_mod_exp (y, &dh_g, dh_power, &dh_prime, BN_ctx));
   out_bignum (y);
   BN_free (y);
 
   BN_init (&auth_key_num);
-  assert (BN_mod_exp (&auth_key_num, &g_a, dh_power, &dh_prime, BN_ctx) == 1);
+  ensure (BN_mod_exp (&auth_key_num, &g_a, dh_power, &dh_prime, BN_ctx));
   l = BN_num_bytes (&auth_key_num);
   assert (l >= 250 && l <= 256);
   assert (BN_bn2bin (&auth_key_num, (unsigned char *)GET_DC(c)->auth_key));
@@ -1098,7 +1099,7 @@ void work_update (struct connection *c UU, long long msg_id UU) {
           bl_do_set_chat_admin (&C->chat, fetch_int ());
           assert (fetch_int () == CODE_vector);
           n = fetch_int ();
-          struct chat_user *users = malloc (12 * n);
+          struct chat_user *users = talloc (12 * n);
           int i;
           for (i = 0; i < n; i++) {
             assert (fetch_int () == (int)CODE_chat_participant);
diff --git a/mtproto-common.c b/mtproto-common.c
index 07d073c..2d87f83 100644
--- a/mtproto-common.c
+++ b/mtproto-common.c
@@ -102,8 +102,7 @@ void my_clock_gettime (int clock_id UU, struct timespec *T) {
 
 
 void prng_seed (const char *password_filename, int password_length) {
-  unsigned char *a = calloc (64 + password_length, 1);
-  assert (a != NULL);
+  unsigned char *a = talloc0 (64 + password_length);
   long long r = rdtsc ();
   struct timespec T;
   my_clock_gettime (CLOCK_REALTIME, &T);
diff --git a/mtproto-common.h b/mtproto-common.h
index b811ecc..0b8bffd 100644
--- a/mtproto-common.h
+++ b/mtproto-common.h
@@ -27,6 +27,7 @@
 #include <stdio.h>
 
 #include "interface.h"
+#include "tools.h"
 #include "constants.h"
 /* DH key exchange protocol data structures */
 #define	CODE_req_pq			0x60469778
@@ -305,7 +306,7 @@ static inline char *fetch_str (int len) {
 static inline char *fetch_str_dup (void) {
   int l = prefetch_strlen ();
   assert (l >= 0);
-  char *s = malloc (l + 1);
+  char *s = talloc (l + 1);
   memcpy (s, fetch_str (l), l);
   s[l] = 0;
   return s;
@@ -320,7 +321,7 @@ static inline int fetch_update_str (char **s) {
   char *r = fetch_str (l);
   if (memcmp (*s, r, l) || (*s)[l]) {
     free (*s);
-    *s = malloc (l + 1);
+    *s = talloc (l + 1);
     memcpy (*s, r, l);
     (*s)[l] = 0;
     return 1;
diff --git a/net.c b/net.c
index c6643f6..3ecfa51 100644
--- a/net.c
+++ b/net.c
@@ -103,9 +103,8 @@ void start_fail_timer (struct connection *c) {
 }
 
 struct connection_buffer *new_connection_buffer (int size) {
-  struct connection_buffer *b = malloc (sizeof (*b));
-  memset (b, 0, sizeof (*b));
-  b->start = malloc (size);
+  struct connection_buffer *b = talloc0 (sizeof (*b));
+  b->start = talloc (size);
   b->end = b->start + size;
   b->rptr = b->wptr = b->start;
   return b;
@@ -224,8 +223,7 @@ void rotate_port (struct connection *c) {
 }
 
 struct connection *create_connection (const char *host, int port, struct session *session, struct connection_methods *methods) {
-  struct connection *c = malloc (sizeof (*c));
-  memset (c, 0, sizeof (*c));
+  struct connection *c = talloc0 (sizeof (*c));
   int fd = socket (AF_INET, SOCK_STREAM, 0);
   if (fd == -1) {
     logprintf ("Can not create socket: %m\n");
@@ -276,7 +274,7 @@ struct connection *create_connection (const char *host, int port, struct session
 
   c->session = session;
   c->fd = fd; 
-  c->ip = strdup (host);
+  c->ip = tstrdup (host);
   c->flags = 0;
   c->state = conn_ready;
   c->methods = methods;
@@ -615,8 +613,7 @@ extern struct dc *DC_list[];
 
 struct dc *alloc_dc (int id, char *ip, int port UU) {
   assert (!DC_list[id]);
-  struct dc *DC = malloc (sizeof (*DC));
-  memset (DC, 0, sizeof (*DC));
+  struct dc *DC = talloc0 (sizeof (*DC));
   DC->id = id;
   DC->ip = ip;
   DC->port = port;
@@ -625,8 +622,7 @@ struct dc *alloc_dc (int id, char *ip, int port UU) {
 }
 
 void dc_create_session (struct dc *DC) {
-  struct session *S = malloc (sizeof (*S));
-  memset (S, 0, sizeof (*S));
+  struct session *S = talloc0 (sizeof (*S));
   assert (RAND_pseudo_bytes ((unsigned char *) &S->session_id, 8) >= 0);
   S->dc = DC;
   S->c = create_connection (DC->ip, DC->port, S, &auth_methods);
diff --git a/queries.c b/queries.c
index bd5a86d..72d6962 100644
--- a/queries.c
+++ b/queries.c
@@ -126,10 +126,9 @@ struct query *send_query (struct dc *DC, int ints, void *data, struct query_meth
   if (verbosity) {
     logprintf ( "Sending query of size %d to DC (%s:%d)\n", 4 * ints, DC->ip, DC->port);
   }
-  struct query *q = malloc (sizeof (*q));
-  memset (q, 0, sizeof (*q));
+  struct query *q = talloc0 (sizeof (*q));
   q->data_len = ints;
-  q->data = malloc (4 * ints);
+  q->data = talloc (4 * ints);
   memcpy (q->data, data, 4 * ints);
   q->msg_id = encrypt_send_message (DC->sessions[0]->c, data, ints, 1);
   q->session = DC->sessions[0];
@@ -436,7 +435,7 @@ char *suser;
 extern int dc_working_num;
 void do_send_code (const char *user) {
   logprintf ("sending code\n");
-  suser = strdup (user);
+  suser = tstrdup (user);
   want_dc_num = 0;
   clear_packet ();
   do_insert_header ();
@@ -527,7 +526,7 @@ struct query_methods check_phone_methods = {
 };
 
 int do_auth_check_phone (const char *user) {
-  suser = strdup (user);
+  suser = tstrdup (user);
   clear_packet ();
   out_int (CODE_auth_check_phone);
   out_string (user);
@@ -1363,8 +1362,7 @@ void send_part (struct send_file *f) {
       out_long (-lrand48 () * (1ll << 32) - lrand48 ());
       send_query (DC_working, packet_ptr - packet_buffer, packet_buffer, &send_file_methods, 0);
     } else {
-      struct message *M = malloc (sizeof (*M));
-      memset (M, 0, sizeof (*M));
+      struct message *M = talloc0 (sizeof (*M));
 
       out_int (CODE_messages_send_encrypted_file);
       out_int (CODE_input_encrypted_chat);
@@ -1446,7 +1444,7 @@ void send_part (struct send_file *f) {
       M->from_id = MK_USER (our_id);
       M->to_id = f->to_id;
       M->unread = 1;
-      M->message = strdup ("");
+      M->message = tstrdup ("");
       M->out = 1;
       M->id = r;
       M->date = time (0);
@@ -1483,8 +1481,7 @@ void do_send_photo (int type, peer_id_t to_id, char *file_name) {
     close (fd);
     return;
   }
-  struct send_file *f = malloc (sizeof (*f));
-  memset (f, 0, sizeof (*f));
+  struct send_file *f = talloc0 (sizeof (*f));
   f->fd = fd;
   f->size = size;
   f->offset = 0;
@@ -1501,11 +1498,11 @@ void do_send_photo (int type, peer_id_t to_id, char *file_name) {
   f->file_name = file_name;
   if (get_peer_type (f->to_id) == PEER_ENCR_CHAT) {
     f->encr = 1;
-    f->iv = malloc (32);
+    f->iv = talloc (32);
     secure_random (f->iv, 32);
-    f->init_iv = malloc (32);
+    f->init_iv = talloc (32);
     memcpy (f->init_iv, f->iv, 32);
-    f->key = malloc (32);
+    f->key = talloc (32);
     secure_random (f->key, 32);
   }
   if (f->part_size > (512 << 10)) {
@@ -1831,7 +1828,7 @@ void load_next_part (struct download *D) {
     } else {
       sprintf (buf, "%s/download_%lld", get_downloads_directory (), D->id);
     }
-    D->name = strdup (buf);
+    D->name = tstrdup (buf);
     struct stat st;
     if (stat (buf, &st) >= 0) {
       D->offset = st.st_size;      
@@ -1878,8 +1875,7 @@ void do_load_photo_size (struct photo_size *P, int next) {
   
   assert (P);
   assert (next);
-  struct download *D = malloc (sizeof (*D));
-  memset (D, 0, sizeof (*D));
+  struct download *D = talloc0 (sizeof (*D));
   D->id = 0;
   D->offset = 0;
   D->size = P->size;
@@ -1918,8 +1914,7 @@ void do_load_document_thumb (struct document *video, int next) {
 void do_load_video (struct video *V, int next) {
   assert (V);
   assert (next);
-  struct download *D = malloc (sizeof (*D));
-  memset (D, 0, sizeof (*D));
+  struct download *D = talloc0 (sizeof (*D));
   D->offset = 0;
   D->size = V->size;
   D->id = V->id;
@@ -1935,8 +1930,7 @@ void do_load_video (struct video *V, int next) {
 void do_load_document (struct document *V, int next) {
   assert (V);
   assert (next);
-  struct download *D = malloc (sizeof (*D));
-  memset (D, 0, sizeof (*D));
+  struct download *D = talloc0 (sizeof (*D));
   D->offset = 0;
   D->size = V->size;
   D->id = V->id;
@@ -1952,8 +1946,7 @@ void do_load_document (struct document *V, int next) {
 void do_load_encr_video (struct encr_video *V, int next) {
   assert (V);
   assert (next);
-  struct download *D = malloc (sizeof (*D));
-  memset (D, 0, sizeof (*D));
+  struct download *D = talloc0 (sizeof (*D));
   D->offset = 0;
   D->size = V->size;
   D->id = V->id;
@@ -1963,7 +1956,7 @@ void do_load_encr_video (struct encr_video *V, int next) {
   D->name = 0;
   D->fd = -1;
   D->key = V->key;
-  D->iv = malloc (32);
+  D->iv = talloc (32);
   memcpy (D->iv, V->iv, 32);
   load_next_part (D);
       
@@ -1995,7 +1988,7 @@ int export_auth_on_answer (struct query *q UU) {
     assert (our_id == l);
   }
   l = prefetch_strlen ();
-  char *s = malloc (l);
+  char *s = talloc (l);
   memcpy (s, fetch_str (l), l);
   export_auth_str_len = l;
   export_auth_str = s;
@@ -2261,18 +2254,19 @@ void do_send_accept_encr_chat (struct secret_chat *E, unsigned char *random) {
     random[i] ^= random_here[i];
   }
   BIGNUM *b = BN_bin2bn (random, 256, 0);
-  assert (b);
+  ensure_ptr (b);
   BIGNUM *g_a = BN_bin2bn (E->g_key, 256, 0);
-  assert (g_a);
+  ensure_ptr (g_a);
   assert (check_g (encr_prime, g_a) >= 0);
   if (!ctx) {
     ctx = BN_CTX_new ();
-    BN_CTX_init (ctx);
+    ensure_ptr (ctx);
   }
   BIGNUM *p = BN_bin2bn (encr_prime, 256, 0); 
+  ensure_ptr (p);
   BIGNUM *r = BN_new ();
-  BN_init (r);
-  BN_mod_exp (r, g_a, b, p, ctx); 
+  ensure_ptr (r);
+  ensure (BN_mod_exp (r, g_a, b, p, ctx));
   static unsigned char kk[256];
   memset (kk, 0, sizeof (kk));
   BN_bn2bin (r, kk);
@@ -2290,8 +2284,8 @@ void do_send_accept_encr_chat (struct secret_chat *E, unsigned char *random) {
   out_int (get_peer_id (E->id));
   out_long (E->access_hash);
   
-  BN_set_word (g_a, encr_root);
-  BN_mod_exp (r, g_a, b, p, ctx); 
+  ensure (BN_set_word (g_a, encr_root));
+  ensure (BN_mod_exp (r, g_a, b, p, ctx));
   static unsigned char buf[256];
   memset (buf, 0, sizeof (buf));
   BN_bn2bin (r, buf);
@@ -2309,19 +2303,21 @@ void do_send_accept_encr_chat (struct secret_chat *E, unsigned char *random) {
 void do_create_keys_end (struct secret_chat *U) {
   assert (encr_prime);
   BIGNUM *g_b = BN_bin2bn (U->g_key, 256, 0);
-  assert (g_b);
+  ensure_ptr (g_b);
   assert (check_g (encr_prime, g_b) >= 0);
   if (!ctx) {
     ctx = BN_CTX_new ();
-    BN_CTX_init (ctx);
+    ensure_ptr (ctx);
   }
   BIGNUM *p = BN_bin2bn (encr_prime, 256, 0); 
+  ensure_ptr (p);
   BIGNUM *r = BN_new ();
+  ensure_ptr (r);
   BIGNUM *a = BN_bin2bn ((void *)U->key, 256, 0);
-  BN_init (r);
-  BN_mod_exp (r, g_b, a, p, ctx); 
+  ensure_ptr (a);
+  ensure (BN_mod_exp (r, g_b, a, p, ctx));
 
-  void *t = malloc (256);
+  void *t = talloc (256);
   memcpy (t, U->key, 256);
   
   memset (U->key, 0, sizeof (U->key));
@@ -2344,6 +2340,9 @@ void do_create_keys_end (struct secret_chat *U) {
     logprintf ("!!Key fingerprint mismatch (my 0x%llx 0x%llx)\n", (unsigned long long)k, (unsigned long long)U->key_fingerprint);
     U->state = sc_deleted;
   }
+
+  memset (t, 0, 256);
+  free (t);
   
   BN_clear_free (p);
   BN_clear_free (g_b);
@@ -2361,21 +2360,24 @@ void do_send_create_encr_chat (void *x, unsigned char *random) {
   }
   if (!ctx) {
     ctx = BN_CTX_new ();
-    BN_CTX_init (ctx);
+    ensure_ptr (ctx);
   }
   BIGNUM *a = BN_bin2bn (random, 256, 0);
-  assert (a);
+  ensure_ptr (a);
   BIGNUM *p = BN_bin2bn (encr_prime, 256, 0); 
+  ensure_ptr (p);
  
   BIGNUM *g = BN_new ();
-  BN_init (g);
+  ensure_ptr (g);
 
-  BN_set_word (g, encr_root);
+  ensure (BN_set_word (g, encr_root));
 
   BIGNUM *r = BN_new ();
-  BN_init (r);
+  ensure_ptr (r);
 
-  BN_mod_exp (r, g, a, p, ctx); 
+  ensure (BN_mod_exp (r, g, a, p, ctx));
+
+  BN_clear_free (a);
 
   static char g_a[256];
   memset (g_a, 0, 256);
@@ -2428,6 +2430,7 @@ int get_dh_config_on_answer (struct query *q UU) {
     bl_do_set_dh_params (a, (void *)s, v);
 
     BIGNUM *p = BN_bin2bn ((void *)s, 256, 0);
+    ensure_ptr (p);
     assert (check_DH_params (p, a) >= 0);
     BN_free (p);      
   }
@@ -2457,7 +2460,7 @@ void do_accept_encr_chat_request (struct secret_chat *E) {
   out_int (CODE_messages_get_dh_config);
   out_int (encr_param_version);
   out_int (256);
-  void **x = malloc (2 * sizeof (void *));
+  void **x = talloc (2 * sizeof (void *));
   x[0] = do_send_accept_encr_chat;
   x[1] = E;
   send_query (DC_working, packet_ptr - packet_buffer, packet_buffer, &get_dh_config_methods, x);
@@ -2468,7 +2471,7 @@ void do_create_encr_chat_request (int user_id) {
   out_int (CODE_messages_get_dh_config);
   out_int (encr_param_version);
   out_int (256);
-  void **x = malloc (2 * sizeof (void *));
+  void **x = talloc (2 * sizeof (void *));
   x[0] = do_send_create_encr_chat;
   x[1] = (void *)(long)(user_id);
   send_query (DC_working, packet_ptr - packet_buffer, packet_buffer, &get_dh_config_methods, x);
diff --git a/structures.c b/structures.c
index 014a8e9..2992fe7 100644
--- a/structures.c
+++ b/structures.c
@@ -179,7 +179,7 @@ char *create_print_name (peer_id_t id, const char *a1, const char *a2, const cha
     assert (cc <= 9999);
     sprintf (s + fl, "#%d", cc);
   }
-  return strdup (s);
+  return tstrdup (s);
 }
 
 /*
@@ -564,7 +564,7 @@ void fetch_chat_full (struct chat *C) {
     admin_id =  fetch_int ();
     assert (fetch_int () == CODE_vector);
     users_num = fetch_int ();
-    users = malloc (sizeof (struct chat_user) * users_num);
+    users = talloc (sizeof (struct chat_user) * users_num);
     int i;
     for (i = 0; i < users_num; i++) {
       assert (fetch_int () == (int)CODE_chat_participant);
@@ -613,8 +613,7 @@ void fetch_photo_size (struct photo_size *S) {
       S->size = fetch_int ();
     } else {
       S->size = prefetch_strlen ();
-//      S->data = malloc (S->size);
-//      assert (S->data);
+//      S->data = talloc (S->size);
       fetch_str (S->size);
 //      memcpy (S->data, fetch_str (S->size), S->size);
     }
@@ -671,7 +670,7 @@ void fetch_photo (struct photo *P) {
   fetch_geo (&P->geo);
   assert (fetch_int () == CODE_vector);
   P->sizes_num = fetch_int ();
-  P->sizes = malloc (sizeof (struct photo_size) * P->sizes_num);
+  P->sizes = talloc (sizeof (struct photo_size) * P->sizes_num);
   int i;
   for (i = 0; i < P->sizes_num; i++) {
     fetch_photo_size (&P->sizes[i]);
@@ -795,7 +794,7 @@ void fetch_message_action (struct message_action *M) {
     M->title = fetch_str_dup ();
     assert (fetch_int () == (int)CODE_vector);
     M->user_num = fetch_int ();
-    M->users = malloc (M->user_num * 4);
+    M->users = talloc (M->user_num * 4);
     fetch_ints (M->users, M->user_num);
     break;
   case CODE_message_action_chat_edit_title:
@@ -1092,14 +1091,14 @@ void fetch_message_media_encrypted (struct message_media *M) {
     
     l = prefetch_strlen  ();
     assert (l > 0);
-    M->encr_photo.key = malloc (32);
+    M->encr_photo.key = talloc (32);
     memset (M->encr_photo.key, 0, 32);
     if (l <= 32) {
       memcpy (M->encr_photo.key + (32 - l), fetch_str (l), l);
     } else {
       memcpy (M->encr_photo.key, fetch_str (l) + (l - 32), 32);
     }
-    M->encr_photo.iv = malloc (32);
+    M->encr_photo.iv = talloc (32);
     l = prefetch_strlen  ();
     assert (l > 0);
     memset (M->encr_photo.iv, 0, 32);
@@ -1122,14 +1121,13 @@ void fetch_message_media_encrypted (struct message_media *M) {
     
     l = prefetch_strlen  ();
     assert (l > 0);
-    M->encr_video.key = malloc (32);
-    memset (M->encr_photo.key, 0, 32);
+    M->encr_video.key = talloc0 (32);
     if (l <= 32) {
       memcpy (M->encr_video.key + (32 - l), fetch_str (l), l);
     } else {
       memcpy (M->encr_video.key, fetch_str (l) + (l - 32), 32);
     }
-    M->encr_video.iv = malloc (32);
+    M->encr_video.iv = talloc (32);
     l = prefetch_strlen  ();
     assert (l > 0);
     memset (M->encr_video.iv, 0, 32);
@@ -1146,17 +1144,15 @@ void fetch_message_media_encrypted (struct message_media *M) {
     
     l = prefetch_strlen  ();
     assert (l > 0);
-    M->encr_video.key = malloc (32);
-    memset (M->encr_photo.key, 0, 32);
+    M->encr_video.key = talloc0 (32);
     if (l <= 32) {
       memcpy (M->encr_video.key + (32 - l), fetch_str (l), l);
     } else {
       memcpy (M->encr_video.key, fetch_str (l) + (l - 32), 32);
     }
-    M->encr_video.iv = malloc (32);
+    M->encr_video.iv = talloc0 (32);
     l = prefetch_strlen  ();
     assert (l > 0);
-    memset (M->encr_video.iv, 0, 32);
     if (l <= 32) {
       memcpy (M->encr_video.iv + (32 - l), fetch_str (l), l);
     } else {
@@ -1175,17 +1171,15 @@ void fetch_message_media_encrypted (struct message_media *M) {
     
     l = prefetch_strlen  ();
     assert (l > 0);
-    M->encr_video.key = malloc (32);
-    memset (M->encr_photo.key, 0, 32);
+    M->encr_video.key = talloc0 (32);
     if (l <= 32) {
       memcpy (M->encr_video.key + (32 - l), fetch_str (l), l);
     } else {
       memcpy (M->encr_video.key, fetch_str (l) + (l - 32), 32);
     }
-    M->encr_video.iv = malloc (32);
+    M->encr_video.iv = talloc0 (32);
     l = prefetch_strlen  ();
     assert (l > 0);
-    memset (M->encr_video.iv, 0, 32);
     if (l <= 32) {
       memcpy (M->encr_video.iv + (32 - l), fetch_str (l), l);
     } else {
@@ -1199,12 +1193,12 @@ void fetch_message_media_encrypted (struct message_media *M) {
     fetch_str (l); // thumb
     l = fetch_int ();
     assert (l > 0);
-    M->encr_file.key = malloc (l);
+    M->encr_file.key = talloc (l);
     memcpy (M->encr_file.key, fetch_str (l), l);
     
     l = fetch_int ();
     assert (l > 0);
-    M->encr_file.iv = malloc (l);
+    M->encr_file.iv = talloc (l);
     memcpy (M->encr_file.iv, fetch_str (l), l);
     break;
   */  
@@ -1521,8 +1515,7 @@ struct user *fetch_alloc_user (void) {
   peer_t *U = user_chat_get (MK_USER (data[1]));
   if (!U) {
     users_allocated ++;
-    U = malloc (sizeof (*U));
-    memset (U, 0, sizeof (*U));
+    U = talloc0 (sizeof (*U));
     U->id = MK_USER (data[1]);
     peer_tree = tree_insert_peer (peer_tree, U, lrand48 ());
     assert (peer_num < MAX_PEER_NUM);
@@ -1537,8 +1530,7 @@ struct secret_chat *fetch_alloc_encrypted_chat (void) {
   prefetch_data (data, 8);
   peer_t *U = user_chat_get (MK_ENCR_CHAT (data[1]));
   if (!U) {
-    U = malloc (sizeof (*U));
-    memset (U, 0, sizeof (*U));
+    U = talloc0 (sizeof (*U));
     U->id = MK_ENCR_CHAT (data[1]);
     encr_chats_allocated ++;
     peer_tree = tree_insert_peer (peer_tree, U, lrand48 ());
@@ -1579,8 +1571,7 @@ struct user *fetch_alloc_user_full (void) {
     return &U->user;
   } else {
     users_allocated ++;
-    U = malloc (sizeof (*U));
-    memset (U, 0, sizeof (*U));
+    U = talloc0 (sizeof (*U));
     U->id = MK_USER (data[2]);
     peer_tree = tree_insert_peer (peer_tree, U, lrand48 ());
     fetch_user_full (&U->user);
@@ -1724,8 +1715,7 @@ void message_add_peer (struct message *M) {
   }
   peer_t *P = user_chat_get (id);
   if (!P) {
-    P = malloc (sizeof (*P));
-    memset (P, 0, sizeof (*P));
+    P = talloc0 (sizeof (*P));
     P->id = id;
     switch (get_peer_type (id)) {
     case PEER_USER:
@@ -1799,8 +1789,7 @@ struct message *fetch_alloc_message (void) {
   struct message *M = message_get (data[1]);
 
   if (!M) {
-    M = malloc (sizeof (*M));
-    memset (M, 0, sizeof (*M));
+    M = talloc0 (sizeof (*M));
     M->id = data[1];
     message_insert_tree (M);
     messages_allocated ++;
@@ -1810,7 +1799,7 @@ struct message *fetch_alloc_message (void) {
 }
 
 struct message *fetch_alloc_geo_message (void) {
-  struct message *M = malloc (sizeof (*M));
+  struct message *M = talloc (sizeof (*M));
   fetch_geo_message (M);
   struct message *M1 = tree_lookup_message (message_tree, M);
   messages_allocated ++;
@@ -1838,8 +1827,7 @@ struct message *fetch_alloc_encrypted_message (void) {
   struct message *M = message_get (*(long long *)(data + 1));
 
   if (!M) {
-    M = malloc (sizeof (*M));
-    memset (M, 0, sizeof (*M));
+    M = talloc0 (sizeof (*M));
     M->id = *(long long *)(data + 1);
     message_insert_tree (M);
     messages_allocated ++;
@@ -1856,8 +1844,7 @@ struct message *fetch_alloc_message_short (void) {
   struct message *M = message_get (data[0]);
 
   if (!M) {
-    M = malloc (sizeof (*M));
-    memset (M, 0, sizeof (*M));
+    M = talloc0 (sizeof (*M));
     M->id = data[0];
     message_insert_tree (M);
     messages_allocated ++;
@@ -1872,8 +1859,7 @@ struct message *fetch_alloc_message_short_chat (void) {
   struct message *M = message_get (data[0]);
 
   if (!M) {
-    M = malloc (sizeof (*M));
-    memset (M, 0, sizeof (*M));
+    M = talloc0 (sizeof (*M));
     M->id = data[0];
     message_insert_tree (M);
     messages_allocated ++;
@@ -1888,8 +1874,7 @@ struct chat *fetch_alloc_chat (void) {
   peer_t *U = user_chat_get (MK_CHAT (data[1]));
   if (!U) {
     chats_allocated ++;
-    U = malloc (sizeof (*U));
-    memset (U, 0, sizeof (*U));
+    U = talloc0 (sizeof (*U));
     U->id = MK_CHAT (data[1]);
     peer_tree = tree_insert_peer (peer_tree, U, lrand48 ());
     assert (peer_num < MAX_PEER_NUM);
@@ -1908,8 +1893,7 @@ struct chat *fetch_alloc_chat_full (void) {
     return &U->chat;
   } else {
     chats_allocated ++;
-    U = malloc (sizeof (*U));
-    memset (U, 0, sizeof (*U));
+    U = talloc0 (sizeof (*U));
     U->id = MK_CHAT (data[2]);
     peer_tree = tree_insert_peer (peer_tree, U, lrand48 ());
     fetch_chat_full (&U->chat);
diff --git a/tools.c b/tools.c
new file mode 100644
index 0000000..bcaa527
--- /dev/null
+++ b/tools.c
@@ -0,0 +1,66 @@
+/*
+    This file is part of telegram-client.
+
+    Telegram-client is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 2 of the License, or
+    (at your option) any later version.
+
+    Telegram-client is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this telegram-client.  If not, see <http://www.gnu.org/licenses/>.
+
+    Copyright Vitaly Valtman 2013
+*/
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <openssl/err.h>
+
+#include "interface.h"
+#include "tools.h"
+
+static void out_of_memory (void) {
+  logprintf ("Out of memory\n");
+  assert (0 && "Out of memory");
+}
+
+void *talloc (size_t size) {
+  void *p = malloc (size);
+  ensure_ptr (p);
+  return p;
+}
+
+void *talloc0 (size_t size) {
+  void *p = talloc (size);
+  memset (p, 0, size);
+  return p;
+}
+
+char *tstrdup (const char *s) {
+  char *p = strdup (s);
+  if (p == NULL) {
+    out_of_memory ();
+  }
+  return p;
+}
+
+void ensure (int r) {
+  if (!r) {
+    logprintf ("Open SSL error\n");
+    ERR_print_errors_fp (stderr);
+    assert (0);
+  }
+}
+
+void ensure_ptr (void *p) {
+  if (p == NULL) {
+    out_of_memory ();
+  }
+}
diff --git a/tools.h b/tools.h
new file mode 100644
index 0000000..f3f7f88
--- /dev/null
+++ b/tools.h
@@ -0,0 +1,29 @@
+/*
+    This file is part of telegram-client.
+
+    Telegram-client is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 2 of the License, or
+    (at your option) any later version.
+
+    Telegram-client is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this telegram-client.  If not, see <http://www.gnu.org/licenses/>.
+
+    Copyright Vitaly Valtman 2013
+*/
+
+#ifndef __TOOLS_H__
+#define __TOOLS_H__
+
+void *talloc (size_t size);
+void *talloc0 (size_t size);
+char *tstrdup (const char *s);
+void ensure (int r);
+void ensure_ptr (void *p);
+
+#endif