checksum_func
typedef krb5_error_code (*checksum_func)(const struct krb5_cksumtypes *ctp,
checksum_func checksum;
auth_context->checksum_func = func;
*func = auth_context->checksum_func;
(*auth_context)->checksum_func = NULL;
krb5_mk_req_checksum_func checksum_func;
if (!in_data && (*auth_context)->checksum_func) {
retval = (*auth_context)->checksum_func( context,
checksum_func *ec_checksum;