3 expanded posts ยท every known parent and child
Is there something like a checksum attached to Credit Card Numbers. Or better: Is there a way to determine for a given number N if -this _might_ be a valid number -this can't be a valid number Thanx, Jens. -- mailto:thielj@cs.bonn.edu Fax: +49 228 747246 http://www.Bonn.CityNet.DE/people/jens
Hi guys,
Long time no post. Credit card numbers are determined by
algorithmns.If s credit card number is no fitting to that algorithmn it
is phoney. The only way that I know of to determine the validity of the
card if a person has a copy of underground algorithmn generating software
is to use the voice number and a store acct # for a purchase of say
$50.00 or to go through the credit bureau.What I have wondered is if
there is a way to determine a experation date from the credit card number.
Bye
moroni
On Tue, 20 Feb 1996, Jens Thiel wrote:
> Is there something like a checksum attached to Credit Card
> Numbers. Or better: Is there a way to determine for a given
> number N if
> -this _might_ be a valid number
> -this can't be a valid number
>
> Thanx,
> Jens.
> --
> mailto:thielj@cs.bonn.edu
> Fax: +49 228 747246
> http://www.Bonn.CityNet.DE/people/jens
>
>> > Is there something like a checksum attached to Credit Card
> > Numbers. Or better: Is there a way to determine for a given
> > number N if
> > -this _might_ be a valid number
> > -this can't be a valid number
This was posted by Wayne D. Hoxsie Jr. <hoxsiew@crl.com>:
#include <stdio.h>
v(char *s)
{
int i=0,j=0,k;
k=!(!s[16]);
for(;*s;*s++)
i+=(++j%2-k)?(*s-'0')*2>9?((*s-'0')*2)-9:(*s-'0')*2:*s-'0';
return (i%10);
}
main()
{
char s[160];
printf("Enter credit card number\n");
scanf("%s",s);
printf("Credit card number is %svalid\n",v(s)?"in":"");
}
---
Dr. Dimitri Vulis
Brighton Beach Boardwalk BBS, Forest Hills, N.Y.: +1-718-261-2013, 14.4Kbps