Re: Crypto software that *is* exportable from the USA

[Paul Sheer <psheer@obsidian.co.za>]

On Sat, 23 Jan 1999, Bear Giles wrote:

> > It supports strong encryption but is exportable from
> > the US because it does not have encryption compiled in by default. Instead
> > it downloads the scripts it needs from South Africa when it runs for the
> > first time.
> 
> This is *extremely* risky behavior. 
> 
> [...]
> 
> > South Africa has no export restrictions on cryptography. It
> > supports file transfer and secure logins shells.
> 

I meant that mirrordir supported file transfer and secure logins shells.
The scripts are downloaded via ordinary ftp.

> 
> As an aside, why would a mirror program even want strong 
> encryption?  Encryption != authentication, although the implementatons
> have significant overlap.
> 
It started as a mirror program. Now its a suite of utilities including a
secure shell.

I don't think the problem is as big as you say. To illustrate, the connect
script follows. We are talking about less than 200 lines of script - an
extremely small amount. It could easily become widely publicisely what
these scripts are. A script to do checksums on the package itself would
only take a few lines. I admit that its not foolproof, but it can easily
reach a point where its highly improbably that a user could have a
compromised script. On the other hand, users would have the ability to do
secure logins on a stock standard system, without having to install a
single thing.

Also: there is no GPL secure shell (as far as I know). So even the
International version of mirrordir with compiled in encryption (i.e. not
in scripts) is a worthwhile package which can be downloaded from outside
the US just like ssh. It seems to have recieved very little attention
considering the need for a GPL secure shell. Is there something that I am
missing here?

-paul


/* client connection script, exporting this script from the US
   may be in violation of the US munitions export regulations */
Huge *r; Huge *s; Huge *p; Huge *q; Huge *g;
Huge *m; Huge *x; Huge *y; Huge *X; Huge *Y;
long l; long type; 
char *c; char *prot;
l = strlen ("dIffIe--HelLmaN\n");
if (l != send ("dIffIe--HelLmaN\n", l, 0))
    return 0;
prot = "1234";
prot[0] = 0;
prot[1] = 1;
type = typeoption ();
prot[2] = type;
prot[3] = 0;
if (send (prot, 4, 0) != 4)
    return 0;
p = prime (type);
g = 2;
y = random (typesize (type));
Y = pow (g, y, p);
if (writehuge (Y, 0))
    return 0;
l = strlen ("DIfFiE--hEllMan\n");
if (recv (&c, l, 0) != l)
    return 1;
if (strncmp ("DIfFiE--hEllMan\n", c, l))
    return 1;
if (!(X = readhuge (0)))
    return 0;
m = pow (X, y, p);
huge2bin (m, &c, &l);
initarcrd (c, l / 2);		/* stream cypher initialisation */
initarcwr (c + l / 2, l / 2);
x = 0;
y = 0;
if (!(y = readhuge (1)))
    return 0;
if (checksavedkey (y, type))
    return 0;
if (!(r = readhuge (1)))
    return 0;
if (!(s = readhuge (1)))
    return 0;
q = p >> 1;
/* signature equation */
if (m != (((pow (g, s, p) * pow (y, r % q, p)) % p * r) % p))
    return 0;
return 1;