diff --git a/library/x509_crt.c b/library/x509_crt.c
index 9a416d3..cdc88ae 100644
--- a/library/x509_crt.c
+++ b/library/x509_crt.c
@@ -559,7 +559,7 @@
 
         /* Get extension ID */
         if( ( ret = mbedtls_asn1_get_tag( p, end_ext_data, &extn_oid.len,
-				  MBEDTLS_ASN1_OID ) ) != 0 )
+                                          MBEDTLS_ASN1_OID ) ) != 0 )
             return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS + ret );
 
         extn_oid.tag = MBEDTLS_ASN1_OID;