diff --git a/programs/pkey/dh_server.c b/programs/pkey/dh_server.c
index aa89fcf..f093576 100644
--- a/programs/pkey/dh_server.c
+++ b/programs/pkey/dh_server.c
@@ -165,7 +165,7 @@
     buf[n    ] = (unsigned char)( rsa.len >> 8 );
     buf[n + 1] = (unsigned char)( rsa.len      );
 
-    if( ( ret = rsa_pkcs1_sign( &rsa, RSA_PRIVATE, SIG_RSA_SHA1,
+    if( ( ret = rsa_pkcs1_sign( &rsa, NULL, NULL, RSA_PRIVATE, SIG_RSA_SHA1,
                                 0, hash, buf + n + 2 ) ) != 0 )
     {
         printf( " failed\n  ! rsa_pkcs1_sign returned %d\n\n", ret );