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 ) );