diff --git a/library/x509_csr.c b/library/x509_csr.c
index a293ec0..79b1589 100644
--- a/library/x509_csr.c
+++ b/library/x509_csr.c
@@ -328,7 +328,7 @@
     }
 
     end = p + len;
-    csr->cri.len = end - csr->cri.p;
+    csr->cri.len = (size_t) (end - csr->cri.p);
 
     /*
      *  Version  ::=  INTEGER {  v1(0) }
@@ -361,7 +361,7 @@
         return ret;
     }
 
-    csr->subject_raw.len = p - csr->subject_raw.p;
+    csr->subject_raw.len = (size_t) (p - csr->subject_raw.p);
 
     /*
      *  subjectPKInfo SubjectPublicKeyInfo