On Sun, Jun 15, 2008 at 10:56 PM, buyoppy <[EMAIL PROTECTED]> wrote:
> I saw a webpage of Solaris's 'isencrypted' function which
> inspects some data in a buffer is encrypted or not using
> some algorithm including statistical analysis. But now I
> cannot find that page on the Internet...
Try this implementation, which I have not tested (or even compiled).
#include <stdlib.h>
#include <zlib.h>
enum {
PLANB_BUF_SIZE = 512;
INADEQUATELY_EXPLAINED_MAGIC_NUMBER = 5;
};
static int incompressible(const char *inbuf, size_t len,
char *outbuf, size_t outlen) {
int rv = compress2(outbuf, outlen, inbuf, len,
INADEQUATELY_EXPLAINED_MAGIC_NUMBER);
if (Z_BUF_ERROR == rv)
return 0; /* it grew. */
else if (Z_MEM_ERROR == rv)
return -1; /* meh, it's a guess. */
else
return rv > len;
}
int isencrypted(const char *buf, size_t len) {
int retval;
char planb_buf[PLANB_BUF_SIZE];
void *out = malloc(len);
if (out) {
retval = incompressible(buf, len, out, len);
free (out);
return retval;
} else {
return incompressible(buf, PLANB_BUF_SIZE, planb_buf, PLANB_BUF_SIZE);
}
}
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