diff --git a/library/x509_crl.c b/library/x509_crl.c
index cad784e..fdbad23 100644
--- a/library/x509_crl.c
+++ b/library/x509_crl.c
@@ -367,7 +367,7 @@
     }
 
     end = p + len;
-    crl->tbs.len = end - crl->tbs.p;
+    crl->tbs.len = (size_t) (end - crl->tbs.p);
 
     /*
      * Version  ::=  INTEGER  OPTIONAL {  v1(0), v2(1)  }
@@ -411,7 +411,7 @@
         return ret;
     }
 
-    crl->issuer_raw.len = p - crl->issuer_raw.p;
+    crl->issuer_raw.len = (size_t) (p - crl->issuer_raw.p);
 
     /*
      * thisUpdate          Time