diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index a617d0629..3c3d9ca2d 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -152,6 +152,7 @@
  * platform function
  */
 //#define MBEDTLS_PLATFORM_EXIT_ALT
+//#define MBEDTLS_PLATFORM_TIME_ALT
 //#define MBEDTLS_PLATFORM_FPRINTF_ALT
 //#define MBEDTLS_PLATFORM_PRINTF_ALT
 //#define MBEDTLS_PLATFORM_SNPRINTF_ALT
@@ -2465,6 +2466,7 @@
 //#define MBEDTLS_PLATFORM_STD_CALLOC        calloc /**< Default allocator to use, can be undefined */
 //#define MBEDTLS_PLATFORM_STD_FREE            free /**< Default free to use, can be undefined */
 //#define MBEDTLS_PLATFORM_STD_EXIT            exit /**< Default exit to use, can be undefined */
+//#define MBEDTLS_PLATFORM_STD_TIME            time /**< Default time to use, can be undefined */
 //#define MBEDTLS_PLATFORM_STD_FPRINTF      fprintf /**< Default fprintf to use, can be undefined */
 //#define MBEDTLS_PLATFORM_STD_PRINTF        printf /**< Default printf to use, can be undefined */
 /* Note: your snprintf must correclty zero-terminate the buffer! */
diff --git a/include/mbedtls/platform.h b/include/mbedtls/platform.h
index 1371ff1c6..7922e8c75 100644
--- a/include/mbedtls/platform.h
+++ b/include/mbedtls/platform.h
@@ -66,6 +66,9 @@ extern "C" {
 #if !defined(MBEDTLS_PLATFORM_STD_EXIT)
 #define MBEDTLS_PLATFORM_STD_EXIT      exit /**< Default exit to use */
 #endif
+#if !defined(MBEDTLS_PLATFORM_STD_TIME)
+#define MBEDTLS_PLATFORM_STD_TIME       time    /**< Default time to use */
+#endif
 #if !defined(MBEDTLS_PLATFORM_STD_EXIT_SUCCESS)
 #define MBEDTLS_PLATFORM_STD_EXIT_SUCCESS  EXIT_SUCCESS /**< Default exit value to use */
 #endif
@@ -227,6 +230,37 @@ int mbedtls_platform_set_exit( void (*exit_func)( int status ) );
 #define MBEDTLS_EXIT_FAILURE 1
 #endif
 
+/*
+ * The time_t datatype
+ */
+#if defined(MBEDTLS_PLATFORM_TIME_T_MACRO)
+#define mbedtls_time_t MBEDTLS_PLATFORM_TIME_T_MACRO
+#else
+#define mbedtls_time_t time_t
+#endif /* MBEDTLS_PLATFORM_TIME_T_MACRO */
+
+/*
+ * The function pointers for time
+ */
+#if defined(MBEDTLS_PLATFORM_TIME_ALT)
+extern time_t (*mbedtls_time)( mbedtls_time_t* time );
+
+/**
+ * \brief   Set your own time function pointer
+ *
+ * \param   time_func   the time function implementation
+ *
+ * \return              0
+ */
+int mbedtls_platform_set_time( mbedtls_time_t (*time_func)( mbedtls_time_t time ) );
+#else
+#if defined(MBEDTLS_PLATFORM_TIME_MACRO)
+#define mbedtls_time    MBEDTLS_PLATFORM_TIME_MACRO
+#else
+#define mbedtls_time   time
+#endif /* MBEDTLS_PLATFORM_TIME_MACRO */
+#endif /* MBEDTLS_PLATFORM_TIME_ALT */
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 3e05f3f3d..67c62b744 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -542,7 +542,7 @@ typedef struct mbedtls_ssl_flight_item mbedtls_ssl_flight_item;
 struct mbedtls_ssl_session
 {
 #if defined(MBEDTLS_HAVE_TIME)
-    time_t start;               /*!< starting time      */
+    mbedtls_time_t start;       /*!< starting time      */
 #endif
     int ciphersuite;            /*!< chosen ciphersuite */
     int compression;            /*!< chosen compression */
diff --git a/include/mbedtls/ssl_cache.h b/include/mbedtls/ssl_cache.h
index 1155924a9..3734bb727 100644
--- a/include/mbedtls/ssl_cache.h
+++ b/include/mbedtls/ssl_cache.h
@@ -60,7 +60,7 @@ typedef struct mbedtls_ssl_cache_entry mbedtls_ssl_cache_entry;
 struct mbedtls_ssl_cache_entry
 {
 #if defined(MBEDTLS_HAVE_TIME)
-    time_t timestamp;           /*!< entry timestamp    */
+    mbedtls_time_t timestamp;           /*!< entry timestamp    */
 #endif
     mbedtls_ssl_session session;        /*!< entry session      */
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
diff --git a/library/debug.c b/library/debug.c
index 4752ab1a3..a032478da 100644
--- a/library/debug.c
+++ b/library/debug.c
@@ -27,21 +27,22 @@
 
 #if defined(MBEDTLS_DEBUG_C)
 
-#include "mbedtls/debug.h"
-
-#include <stdarg.h>
-#include <stdio.h>
-#include <string.h>
-
 #if defined(MBEDTLS_PLATFORM_C)
 #include "mbedtls/platform.h"
 #else
 #include <stdlib.h>
 #define mbedtls_calloc      calloc
 #define mbedtls_free        free
+#define mbedtls_time_t      time_t
 #define mbedtls_snprintf    snprintf
 #endif
 
+#include "mbedtls/debug.h"
+
+#include <stdarg.h>
+#include <stdio.h>
+#include <string.h>
+
 #if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
     !defined(inline) && !defined(__cplusplus)
 #define inline __inline
diff --git a/library/net.c b/library/net.c
index 3b78b6b15..4142bc061 100644
--- a/library/net.c
+++ b/library/net.c
@@ -32,6 +32,13 @@
 #error "This module only works on Unix and Windows, see MBEDTLS_NET_C in config.h"
 #endif
 
+#if defined(MBEDTLS_PLATFORM_C)
+#include "mbedtls/platform.h"
+#else
+#include <stdlib.h>
+#define mbedtls_time_t    time_t
+#endif
+
 #include "mbedtls/net.h"
 
 #include <string.h>
@@ -86,7 +93,6 @@ static int wsa_init_done = 0;
 #define MSVC_INT_CAST
 #endif
 
-#include <stdlib.h>
 #include <stdio.h>
 
 #include <time.h>
diff --git a/library/platform.c b/library/platform.c
index d634c6277..e7ec0ad6a 100644
--- a/library/platform.c
+++ b/library/platform.c
@@ -190,4 +190,27 @@ int mbedtls_platform_set_exit( void (*exit_func)( int status ) )
 }
 #endif /* MBEDTLS_PLATFORM_EXIT_ALT */
 
+#if defined(MBEDTLS_PLATFORM_TIME_ALT)
+#if !defined(MBEDTLS_PLATFORM_STD_TIME)
+/*
+ * Make dummy function to prevent NULL pointer dereferences
+ */
+static mbedtls_time_t platform_time_uninit( mbedtls_time_t* timer )
+{
+    ((void) timer);
+    return( NULL );
+}
+
+#define MBEDTLS_PLATFORM_STD_TIME   platform_time_uninit
+#endif /* !MBEDTLS_PLATFORM_STD_TIME */
+
+time_t (*mbedtls_time)( mbedtls_time_t* timer ) = MBEDTLS_PLATFORM_STD_TIME;
+
+int mbedtls_platform_set_exit( mbedtls_time_t (*time_func)( mbedtls_time_t timer ) )
+{
+    mbedtls_time = time_func;
+    return( 0 );
+}
+#endif /* MBEDTLS_PLATFORM_TIME_ALT */
+
 #endif /* MBEDTLS_PLATFORM_C */
diff --git a/library/ssl_cache.c b/library/ssl_cache.c
index 711bc535c..01c66aed1 100644
--- a/library/ssl_cache.c
+++ b/library/ssl_cache.c
@@ -31,18 +31,20 @@
 
 #if defined(MBEDTLS_SSL_CACHE_C)
 
-#include "mbedtls/ssl_cache.h"
-
-#include <string.h>
-
 #if defined(MBEDTLS_PLATFORM_C)
 #include "mbedtls/platform.h"
 #else
 #include <stdlib.h>
 #define mbedtls_calloc    calloc
-#define mbedtls_free       free
+#define mbedtls_free      free
+#define mbedtls_time      time
+#define mbedtls_time_t    time_t
 #endif
 
+#include "mbedtls/ssl_cache.h"
+
+#include <string.h>
+
 void mbedtls_ssl_cache_init( mbedtls_ssl_cache_context *cache )
 {
     memset( cache, 0, sizeof( mbedtls_ssl_cache_context ) );
@@ -59,7 +61,7 @@ int mbedtls_ssl_cache_get( void *data, mbedtls_ssl_session *session )
 {
     int ret = 1;
 #if defined(MBEDTLS_HAVE_TIME)
-    time_t t = time( NULL );
+    mbedtls_time_t t = mbedtls_time( NULL );
 #endif
     mbedtls_ssl_cache_context *cache = (mbedtls_ssl_cache_context *) data;
     mbedtls_ssl_cache_entry *cur, *entry;
@@ -138,7 +140,7 @@ int mbedtls_ssl_cache_set( void *data, const mbedtls_ssl_session *session )
 {
     int ret = 1;
 #if defined(MBEDTLS_HAVE_TIME)
-    time_t t = time( NULL ), oldest = 0;
+    mbedtls_time_t t = time( NULL ), oldest = 0;
     mbedtls_ssl_cache_entry *old = NULL;
 #endif
     mbedtls_ssl_cache_context *cache = (mbedtls_ssl_cache_context *) data;
diff --git a/library/ssl_ciphersuites.c b/library/ssl_ciphersuites.c
index 949b9ed64..35463317f 100644
--- a/library/ssl_ciphersuites.c
+++ b/library/ssl_ciphersuites.c
@@ -29,10 +29,16 @@
 
 #if defined(MBEDTLS_SSL_TLS_C)
 
+#if defined(MBEDTLS_PLATFORM_C)
+#include "mbedtls/platform.h"
+#else
+#include <stdlib.h>
+#define mbedtls_time_t    time_t
+#endif
+
 #include "mbedtls/ssl_ciphersuites.h"
 #include "mbedtls/ssl.h"
 
-// #include <stdlib.h>
 #include <string.h>
 
 /*
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 7f5b94eb2..cd39db027 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -27,20 +27,22 @@
 
 #if defined(MBEDTLS_SSL_CLI_C)
 
-#include "mbedtls/debug.h"
-#include "mbedtls/ssl.h"
-#include "mbedtls/ssl_internal.h"
-
-#include <string.h>
-
 #if defined(MBEDTLS_PLATFORM_C)
 #include "mbedtls/platform.h"
 #else
 #include <stdlib.h>
 #define mbedtls_calloc    calloc
-#define mbedtls_free       free
+#define mbedtls_free      free
+#define mbedtls_time      time
+#define mbedtls_time_t    time_t
 #endif
 
+#include "mbedtls/debug.h"
+#include "mbedtls/ssl.h"
+#include "mbedtls/ssl_internal.h"
+
+#include <string.h>
+
 #include <stdint.h>
 
 #if defined(MBEDTLS_HAVE_TIME)
@@ -669,7 +671,7 @@ static int ssl_generate_random( mbedtls_ssl_context *ssl )
     int ret;
     unsigned char *p = ssl->handshake->randbytes;
 #if defined(MBEDTLS_HAVE_TIME)
-    time_t t;
+    mbedtls_time_t t;
 #endif
 
     /*
@@ -684,7 +686,7 @@ static int ssl_generate_random( mbedtls_ssl_context *ssl )
 #endif
 
 #if defined(MBEDTLS_HAVE_TIME)
-    t = time( NULL );
+    t = mbedtls_time( NULL );
     *p++ = (unsigned char)( t >> 24 );
     *p++ = (unsigned char)( t >> 16 );
     *p++ = (unsigned char)( t >>  8 );
@@ -1592,7 +1594,7 @@ static int ssl_parse_server_hello( mbedtls_ssl_context *ssl )
         ssl->state++;
         ssl->handshake->resume = 0;
 #if defined(MBEDTLS_HAVE_TIME)
-        ssl->session_negotiate->start = time( NULL );
+        ssl->session_negotiate->start = mbedtls_time( NULL );
 #endif
         ssl->session_negotiate->ciphersuite = i;
         ssl->session_negotiate->compression = comp;
diff --git a/library/ssl_cookie.c b/library/ssl_cookie.c
index 7e0c573ad..f241c86d8 100644
--- a/library/ssl_cookie.c
+++ b/library/ssl_cookie.c
@@ -31,16 +31,18 @@
 
 #if defined(MBEDTLS_SSL_COOKIE_C)
 
-#include "mbedtls/ssl_cookie.h"
-#include "mbedtls/ssl_internal.h"
-
 #if defined(MBEDTLS_PLATFORM_C)
 #include "mbedtls/platform.h"
 #else
 #define mbedtls_calloc    calloc
-#define mbedtls_free       free
+#define mbedtls_free      free
+#define mbedtls_time      time
+#define mbedtls_time_t    time_t
 #endif
 
+#include "mbedtls/ssl_cookie.h"
+#include "mbedtls/ssl_internal.h"
+
 #include <string.h>
 
 /* Implementation that should never be optimized out by the compiler */
@@ -172,7 +174,7 @@ int mbedtls_ssl_cookie_write( void *p_ctx,
         return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
 
 #if defined(MBEDTLS_HAVE_TIME)
-    t = (unsigned long) time( NULL );
+    t = (unsigned long) mbedtls_time( NULL );
 #else
     t = ctx->serial++;
 #endif
@@ -242,7 +244,7 @@ int mbedtls_ssl_cookie_check( void *p_ctx,
         return( -1 );
 
 #if defined(MBEDTLS_HAVE_TIME)
-    cur_time = (unsigned long) time( NULL );
+    cur_time = (unsigned long) mbedtls_time( NULL );
 #else
     cur_time = ctx->serial;
 #endif
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index 6bd0b598a..9fc21a5ef 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -27,6 +27,16 @@
 
 #if defined(MBEDTLS_SSL_SRV_C)
 
+#if defined(MBEDTLS_PLATFORM_C)
+#include "mbedtls/platform.h"
+#else
+#include <stdlib.h>
+#define mbedtls_calloc    calloc
+#define mbedtls_free      free
+#define mbedtls_time      time
+#define mbedtls_time_t    time_t
+#endif
+
 #include "mbedtls/debug.h"
 #include "mbedtls/ssl.h"
 #include "mbedtls/ssl_internal.h"
@@ -37,14 +47,6 @@
 #include "mbedtls/ecp.h"
 #endif
 
-#if defined(MBEDTLS_PLATFORM_C)
-#include "mbedtls/platform.h"
-#else
-#include <stdlib.h>
-#define mbedtls_calloc    calloc
-#define mbedtls_free       free
-#endif
-
 #if defined(MBEDTLS_HAVE_TIME)
 #include <time.h>
 #endif
@@ -2210,7 +2212,7 @@ static int ssl_write_hello_verify_request( mbedtls_ssl_context *ssl )
 static int ssl_write_server_hello( mbedtls_ssl_context *ssl )
 {
 #if defined(MBEDTLS_HAVE_TIME)
-    time_t t;
+    mbedtls_time_t t;
 #endif
     int ret;
     size_t olen, ext_len = 0, n;
@@ -2253,7 +2255,7 @@ static int ssl_write_server_hello( mbedtls_ssl_context *ssl )
                         buf[4], buf[5] ) );
 
 #if defined(MBEDTLS_HAVE_TIME)
-    t = time( NULL );
+    t = mbedtls_time( NULL );
     *p++ = (unsigned char)( t >> 24 );
     *p++ = (unsigned char)( t >> 16 );
     *p++ = (unsigned char)( t >>  8 );
@@ -2302,7 +2304,7 @@ static int ssl_write_server_hello( mbedtls_ssl_context *ssl )
         ssl->state++;
 
 #if defined(MBEDTLS_HAVE_TIME)
-        ssl->session_negotiate->start = time( NULL );
+        ssl->session_negotiate->start = mbedtls_time( NULL );
 #endif
 
 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
diff --git a/library/ssl_ticket.c b/library/ssl_ticket.c
index 0e27900b5..5d77403e5 100644
--- a/library/ssl_ticket.c
+++ b/library/ssl_ticket.c
@@ -27,16 +27,18 @@
 
 #if defined(MBEDTLS_SSL_TICKET_C)
 
-#include "mbedtls/ssl_ticket.h"
-
 #if defined(MBEDTLS_PLATFORM_C)
 #include "mbedtls/platform.h"
 #else
 #include <stdlib.h>
 #define mbedtls_calloc    calloc
-#define mbedtls_free       free
+#define mbedtls_free      free
+#define mbedtls_time      time
+#define mbedtls_time_t    time_t
 #endif
 
+#include "mbedtls/ssl_ticket.h"
+
 #include <string.h>
 
 /* Implementation that should never be optimized out by the compiler */
@@ -69,7 +71,7 @@ static int ssl_ticket_gen_key( mbedtls_ssl_ticket_context *ctx,
     mbedtls_ssl_ticket_key *key = ctx->keys + index;
 
 #if defined(MBEDTLS_HAVE_TIME)
-    key->generation_time = (uint32_t) time( NULL );
+    key->generation_time = (uint32_t) mbedtls_time( NULL );
 #endif
 
     if( ( ret = ctx->f_rng( ctx->p_rng, key->name, sizeof( key->name ) ) ) != 0 )
@@ -98,7 +100,7 @@ static int ssl_ticket_update_keys( mbedtls_ssl_ticket_context *ctx )
 #else
     if( ctx->ticket_lifetime != 0 )
     {
-        uint32_t current_time = (uint32_t) time( NULL );
+        uint32_t current_time = (uint32_t) mbedtls_time( NULL );
         uint32_t key_time = ctx->keys[ctx->active].generation_time;
 
         if( current_time > key_time &&
@@ -451,7 +453,7 @@ int mbedtls_ssl_ticket_parse( void *p_ticket,
 #if defined(MBEDTLS_HAVE_TIME)
     {
         /* Check for expiration */
-        time_t current_time = time( NULL );
+        mbedtls_time_t current_time = mbedtls_time( NULL );
 
         if( current_time < session->start ||
             (uint32_t)( current_time - session->start ) > ctx->ticket_lifetime )
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 1c44b7ddb..19cc35792 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -35,6 +35,15 @@
 
 #if defined(MBEDTLS_SSL_TLS_C)
 
+#if defined(MBEDTLS_PLATFORM_C)
+#include "mbedtls/platform.h"
+#else
+#include <stdlib.h>
+#define mbedtls_calloc    calloc
+#define mbedtls_free      free
+#define mbedtls_time_t    time_t
+#endif
+
 #include "mbedtls/debug.h"
 #include "mbedtls/ssl.h"
 #include "mbedtls/ssl_internal.h"
@@ -46,14 +55,6 @@
 #include "mbedtls/oid.h"
 #endif
 
-#if defined(MBEDTLS_PLATFORM_C)
-#include "mbedtls/platform.h"
-#else
-#include <stdlib.h>
-#define mbedtls_calloc    calloc
-#define mbedtls_free       free
-#endif
-
 /* Implementation that should never be optimized out by the compiler */
 static void mbedtls_zeroize( void *v, size_t n ) {
     volatile unsigned char *p = v; while( n-- ) *p++ = 0;
diff --git a/library/x509.c b/library/x509.c
index ffc3d6c94..a0df81708 100644
--- a/library/x509.c
+++ b/library/x509.c
@@ -53,10 +53,12 @@
 #else
 #include <stdio.h>
 #include <stdlib.h>
-#define mbedtls_free       free
+#define mbedtls_free      free
 #define mbedtls_calloc    calloc
-#define mbedtls_printf     printf
-#define mbedtls_snprintf   snprintf
+#define mbedtls_time      time
+#define mbedtls_time_t    time_t
+#define mbedtls_printf    printf
+#define mbedtls_snprintf  snprintf
 #endif
 
 #if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)
@@ -843,7 +845,7 @@ static int x509_get_current_time( mbedtls_x509_time *now )
 static int x509_get_current_time( mbedtls_x509_time *now )
 {
     struct tm *lt;
-    time_t tt;
+    mbedtls_time_t tt;
     int ret = 0;
 
 #if defined(MBEDTLS_THREADING_C)
@@ -851,7 +853,7 @@ static int x509_get_current_time( mbedtls_x509_time *now )
         return( MBEDTLS_ERR_THREADING_MUTEX_ERROR );
 #endif
 
-    tt = time( NULL );
+    tt = mbedtls_time( NULL );
     lt = gmtime( &tt );
 
     if( lt == NULL )
diff --git a/programs/ssl/mini_client.c b/programs/ssl/mini_client.c
index 26082ef5b..d3954c571 100644
--- a/programs/ssl/mini_client.c
+++ b/programs/ssl/mini_client.c
@@ -43,12 +43,14 @@
 #if !defined(MBEDTLS_CTR_DRBG_C) || !defined(MBEDTLS_ENTROPY_C) || \
     !defined(MBEDTLS_NET_C) || !defined(MBEDTLS_SSL_CLI_C) || \
     !defined(UNIX)
+
 #if defined(MBEDTLS_PLATFORM_C)
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
 #define mbedtls_printf printf
 #endif
+
 int main( void )
 {
     mbedtls_printf( "MBEDTLS_CTR_DRBG_C and/or MBEDTLS_ENTROPY_C and/or "
@@ -58,6 +60,15 @@ int main( void )
 }
 #else
 
+#if defined(MBEDTLS_PLATFORM_C)
+#include "mbedtls/platform.h"
+#else
+#include <stdlib.h>
+#define mbedtls_time_t       time_t
+#define MBEDTLS_EXIT_SUCCESS EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE EXIT_FAILURE
+#endif
+
 #include <string.h>
 
 #include "mbedtls/net.h"