diff --git a/crypto/x509/x509name.c b/crypto/x509/x509name.c
index fa621f2..fbb76f0 100644
--- a/crypto/x509/x509name.c
+++ b/crypto/x509/x509name.c
@@ -177,7 +177,7 @@
 }
 
 int X509_NAME_add_entry_by_OBJ(X509_NAME *name, ASN1_OBJECT *obj, int type,
-                               unsigned char *bytes, int len, int loc,
+                               const unsigned char *bytes, int len, int loc,
                                int set)
 {
     X509_NAME_ENTRY *ne;
@@ -191,7 +191,7 @@
 }
 
 int X509_NAME_add_entry_by_NID(X509_NAME *name, int nid, int type,
-                               unsigned char *bytes, int len, int loc,
+                               const unsigned char *bytes, int len, int loc,
                                int set)
 {
     X509_NAME_ENTRY *ne;
@@ -298,7 +298,8 @@
 }
 
 X509_NAME_ENTRY *X509_NAME_ENTRY_create_by_NID(X509_NAME_ENTRY **ne, int nid,
-                                               int type, unsigned char *bytes,
+                                               int type,
+                                               const unsigned char *bytes,
                                                int len)
 {
     const ASN1_OBJECT *obj = OBJ_nid2obj(nid);
diff --git a/include/openssl/x509.h b/include/openssl/x509.h
index 438212c..7bf4923 100644
--- a/include/openssl/x509.h
+++ b/include/openssl/x509.h
@@ -959,13 +959,13 @@
 OPENSSL_EXPORT int 		X509_NAME_add_entry(X509_NAME *name,X509_NAME_ENTRY *ne,
 			int loc, int set);
 OPENSSL_EXPORT int X509_NAME_add_entry_by_OBJ(X509_NAME *name, ASN1_OBJECT *obj, int type,
-			unsigned char *bytes, int len, int loc, int set);
+			const unsigned char *bytes, int len, int loc, int set);
 OPENSSL_EXPORT int X509_NAME_add_entry_by_NID(X509_NAME *name, int nid, int type,
-			unsigned char *bytes, int len, int loc, int set);
+			const unsigned char *bytes, int len, int loc, int set);
 OPENSSL_EXPORT X509_NAME_ENTRY *X509_NAME_ENTRY_create_by_txt(X509_NAME_ENTRY **ne,
 		const char *field, int type, const unsigned char *bytes, int len);
 OPENSSL_EXPORT X509_NAME_ENTRY *X509_NAME_ENTRY_create_by_NID(X509_NAME_ENTRY **ne, int nid,
-			int type,unsigned char *bytes, int len);
+			int type, const unsigned char *bytes, int len);
 OPENSSL_EXPORT int X509_NAME_add_entry_by_txt(X509_NAME *name, const char *field, int type,
 			const unsigned char *bytes, int len, int loc, int set);
 OPENSSL_EXPORT X509_NAME_ENTRY *X509_NAME_ENTRY_create_by_OBJ(X509_NAME_ENTRY **ne,