diff --git a/VMS/vms_idhacks.h b/VMS/vms_idhacks.h
index 1e980ede3e6d6346aaff69abf4bdf8e65466e2ca..cc4b0d8b32e33676876cc7f1c0fb6ab9103152b6 100644
--- a/VMS/vms_idhacks.h
+++ b/VMS/vms_idhacks.h
@@ -57,6 +57,8 @@
 
 #ifdef VMS
 
+/* Hack a long name in crypto/asn1/a_mbstr.c */
+#define ASN1_STRING_set_default_mask_asc ASN1_STRING_set_def_mask_asc
 /* Hack the names created with DECLARE_STACK_OF(PKCS7_SIGNER_INFO) */
 #define sk_PKCS7_SIGNER_INFO_new	sk_PKCS7_SIGINF_new
 #define sk_PKCS7_SIGNER_INFO_new_null	sk_PKCS7_SIGINF_new_null