diff --git a/library/entropy.c b/library/entropy.c
index cdbd35c..3622ad2 100644
--- a/library/entropy.c
+++ b/library/entropy.c
@@ -112,24 +112,24 @@
                         mbedtls_entropy_f_source_ptr f_source, void *p_source,
                         size_t threshold, int strong )
 {
-    int index, ret = 0;
+    int idx, ret = 0;
 
 #if defined(MBEDTLS_THREADING_C)
     if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
         return( ret );
 #endif
 
-    index = ctx->source_count;
-    if( index >= MBEDTLS_ENTROPY_MAX_SOURCES )
+    idx = ctx->source_count;
+    if( idx >= MBEDTLS_ENTROPY_MAX_SOURCES )
     {
         ret = MBEDTLS_ERR_ENTROPY_MAX_SOURCES;
         goto exit;
     }
 
-    ctx->source[index].f_source  = f_source;
-    ctx->source[index].p_source  = p_source;
-    ctx->source[index].threshold = threshold;
-    ctx->source[index].strong    = strong;
+    ctx->source[idx].f_source  = f_source;
+    ctx->source[idx].p_source  = p_source;
+    ctx->source[idx].threshold = threshold;
+    ctx->source[idx].strong    = strong;
 
     ctx->source_count++;
 
diff --git a/library/x509.c b/library/x509.c
index 072e3ac..e87ba69 100644
--- a/library/x509.c
+++ b/library/x509.c
@@ -491,25 +491,25 @@
     return( 0 );
 }
 
-static int x509_date_is_valid(const mbedtls_x509_time *time)
+static int x509_date_is_valid(const mbedtls_x509_time *t)
 {
     int ret = MBEDTLS_ERR_X509_INVALID_DATE;
 
-    CHECK_RANGE( 0, 9999, time->year );
-    CHECK_RANGE( 0, 23,   time->hour );
-    CHECK_RANGE( 0, 59,   time->min  );
-    CHECK_RANGE( 0, 59,   time->sec  );
+    CHECK_RANGE( 0, 9999, t->year );
+    CHECK_RANGE( 0, 23,   t->hour );
+    CHECK_RANGE( 0, 59,   t->min  );
+    CHECK_RANGE( 0, 59,   t->sec  );
 
-    switch( time->mon )
+    switch( t->mon )
     {
         case 1: case 3: case 5: case 7: case 8: case 10: case 12:
-            CHECK_RANGE( 1, 31, time->day );
+            CHECK_RANGE( 1, 31, t->day );
             break;
         case 4: case 6: case 9: case 11:
-            CHECK_RANGE( 1, 30, time->day );
+            CHECK_RANGE( 1, 30, t->day );
             break;
         case 2:
-            CHECK_RANGE( 1, 28 + (time->year % 4 == 0), time->day );
+            CHECK_RANGE( 1, 28 + (t->year % 4 == 0), t->day );
             break;
         default:
             return( ret );
@@ -523,7 +523,7 @@
  * field.
  */
 static int x509_parse_time( unsigned char **p, size_t len, size_t yearlen,
-        mbedtls_x509_time *time )
+                            mbedtls_x509_time *tm )
 {
     int ret;
 
@@ -537,26 +537,26 @@
     /*
      * Parse year, month, day, hour, minute
      */
-    CHECK( x509_parse_int( p, yearlen, &time->year ) );
+    CHECK( x509_parse_int( p, yearlen, &tm->year ) );
     if ( 2 == yearlen )
     {
-        if ( time->year < 50 )
-            time->year += 100;
+        if ( tm->year < 50 )
+            tm->year += 100;
 
-        time->year += 1900;
+        tm->year += 1900;
     }
 
-    CHECK( x509_parse_int( p, 2, &time->mon ) );
-    CHECK( x509_parse_int( p, 2, &time->day ) );
-    CHECK( x509_parse_int( p, 2, &time->hour ) );
-    CHECK( x509_parse_int( p, 2, &time->min ) );
+    CHECK( x509_parse_int( p, 2, &tm->mon ) );
+    CHECK( x509_parse_int( p, 2, &tm->day ) );
+    CHECK( x509_parse_int( p, 2, &tm->hour ) );
+    CHECK( x509_parse_int( p, 2, &tm->min ) );
 
     /*
      * Parse seconds if present
      */
     if ( len >= 2 )
     {
-        CHECK( x509_parse_int( p, 2, &time->sec ) );
+        CHECK( x509_parse_int( p, 2, &tm->sec ) );
         len -= 2;
     }
     else
@@ -577,7 +577,7 @@
     if ( 0 != len )
         return ( MBEDTLS_ERR_X509_INVALID_DATE );
 
-    CHECK( x509_date_is_valid( time ) );
+    CHECK( x509_date_is_valid( tm ) );
 
     return ( 0 );
 }
@@ -588,7 +588,7 @@
  *       generalTime    GeneralizedTime }
  */
 int mbedtls_x509_get_time( unsigned char **p, const unsigned char *end,
-                   mbedtls_x509_time *time )
+                           mbedtls_x509_time *tm )
 {
     int ret;
     size_t len, year_len;
@@ -614,7 +614,7 @@
     if( ret != 0 )
         return( MBEDTLS_ERR_X509_INVALID_DATE + ret );
 
-    return x509_parse_time( p, len, year_len, time );
+    return x509_parse_time( p, len, year_len, tm );
 }
 
 int mbedtls_x509_get_sig( unsigned char **p, const unsigned char *end, mbedtls_x509_buf *sig )
diff --git a/library/x509write_crt.c b/library/x509write_crt.c
index d1d9a22..4d674ab 100644
--- a/library/x509write_crt.c
+++ b/library/x509write_crt.c
@@ -264,7 +264,7 @@
 }
 
 static int x509_write_time( unsigned char **p, unsigned char *start,
-                            const char *time, size_t size )
+                            const char *t, size_t size )
 {
     int ret;
     size_t len = 0;
@@ -272,10 +272,10 @@
     /*
      * write MBEDTLS_ASN1_UTC_TIME if year < 2050 (2 bytes shorter)
      */
-    if( time[0] == '2' && time[1] == '0' && time [2] < '5' )
+    if( t[0] == '2' && t[1] == '0' && t[2] < '5' )
     {
         MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start,
-                                             (const unsigned char *) time + 2,
+                                             (const unsigned char *) t + 2,
                                              size - 2 ) );
         MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
         MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_UTC_TIME ) );
@@ -283,7 +283,7 @@
     else
     {
         MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start,
-                                                  (const unsigned char *) time,
+                                                  (const unsigned char *) t,
                                                   size ) );
         MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
         MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_GENERALIZED_TIME ) );