RC4 in C
John Allen wrote this smaller version of rc4 in C which takes a hex key as
it's argument.
<![CDATA[
#define S ,t=s[i],s[i]=s[j],s[j]=t /* rc4 hexkey <file */
unsigned char k[256],s[256],i,j,t;main(c,v,e)char**v;{++v;while(++i)s[
i]=i;for(c=0;*(*v)++;k[c++]=e)sscanf((*v)++-1,"%2x",&e);while(j+=s[i]
+k[i%c]S,++i);for(j=0;c=~getchar();putchar(~c^s[t+=s[i]]))j+=s[++i]S;}
]]>
The usage is the same as the rc4 in perl, and
the (uncompacted) rc4 in C, that is:
<![CDATA[
% rc4 hexkey < input > output
]]>
Compile it like this:
<![CDATA[
% gcc -o rc4 -O4 rc4.c
]]>
This is lots faster than rc4 in perl.
Comments, html bugs to me
(Adam Back) at
<adam@cypherspace.org>