diff --git a/cryptography/hazmat/backends/openssl/asn1.py b/cryptography/hazmat/backends/openssl/asn1.py
index bf3cf48..c638223 100644
--- a/cryptography/hazmat/backends/openssl/asn1.py
+++ b/cryptography/hazmat/backends/openssl/asn1.py
@@ -33,7 +33,7 @@
  * <fijal> I think you want to declare your value too large (e.g. long)
  * <fijal> that way you'll never pass garbage
  */
-typedef uintptr_t time_t;
+typedef intptr_t time_t;
 
 typedef int ASN1_BOOLEAN;
 typedef ... ASN1_INTEGER;