implement Createsignerkey; include "sys.m";	sys: Sys; include "draw.m"; include "daytime.m"; include "keyring.m";	kr: Keyring; include "arg.m"; # signer key never expiresSKexpire:       con 0; # size in bits of modulus for public keysPKmodlen:		con 512; # size in bits of modulus for diffie hellmanDHmodlen:		con 512; algs := array[] of {"rsa", "elgamal"};	# first entry is default Createsignerkey: module{	init:	fn(ctxt: ref Draw->Context, argv: list of string);}; init(nil: ref Draw->Context, argv: list of string){	err: string; 	sys = load Sys Sys->PATH;	kr = load Keyring Keyring->PATH;	if(kr == nil)		loaderr(Keyring->PATH);	arg := load Arg Arg->PATH;	if(arg == nil)		loaderr(Arg->PATH); 	arg->init(argv);	arg->setusage("createsignerkey [-a algorithm] [-f keyfile] [-e ddmmyyyy] [-b size-in-bits] name-of-owner");	alg := algs[0];	filename := "/keydb/signerkey";	expire := SKexpire;	bits := PKmodlen;	while((c := arg->opt()) != 0){		case c {		'a' =>			alg = arg->arg();			if(alg == nil)				arg->usage();			for(i:=0;; i++){				if(i >= len algs)					error(sys->sprint("unknown algorithm: %s", alg));				else if(alg == algs[i])					break;			}		'f' or 'k' =>			filename = arg->earg();		'e' =>			s := arg->earg();			(err, expire) = checkdate(s);			if(err != nil)				error(err);		'b' =>			s := arg->earg();			bits = int s;			if(bits < 32 || bits > 4096)				error("modulus must be in the range of 32 to 4096 bits");		* =>			arg->usage();		}	}	argv = arg->argv();	if(argv == nil)		arg->usage();	arg = nil; 	owner := hd argv; 	# generate a local key, self-signed	info := ref Keyring->Authinfo;	info.mysk = kr->genSK(alg, owner, bits);	if(info.mysk == nil)		error(sys->sprint("algorithm %s not configured in system", alg));	info.mypk = kr->sktopk(info.mysk);	info.spk = kr->sktopk(info.mysk);	myPKbuf := array of byte kr->pktostr(info.mypk);	state := kr->sha1(myPKbuf, len myPKbuf, nil, nil);	info.cert = kr->sign(info.mysk, expire, state, "sha1");	(info.alpha, info.p) = kr->dhparams(DHmodlen); 	if(kr->writeauthinfo(filename, info) < 0)		error(sys->sprint("can't write signerkey file %s: %r", filename));} loaderr(s: string){	error(sys->sprint("can't load %s: %r", s));} error(s: string){	sys->fprint(sys->fildes(2), "createsignerkey: %s\n", s);	raise "fail:error";} checkdate(word: string): (string, int){	if(len word != 8)		return ("!date must be in form ddmmyyyy", 0); 	daytime := load Daytime Daytime->PATH;	if(daytime == nil)		loaderr(Daytime->PATH); 	now := daytime->now(); 	tm := daytime->local(now);	tm.sec = 59;	tm.min = 59;	tm.hour = 24; 	tm.mday = int word[0:2];	if(tm.mday > 31 || tm.mday < 1)		return ("!bad day of month", 0); 	tm.mon = int word[2:4] - 1;	if(tm.mon > 11 || tm.mday < 0)		return ("!bad month", 0); 	tm.year = int word[4:8] - 1900;	if(tm.year < 70)		return ("!bad year", 0); 	newdate := daytime->tm2epoch(tm);	if(newdate < now)		return ("!expiration date must be in the future", 0); 	return (nil, newdate);}