Superficial image obfuscator

crypto.c

@@ -0,0 +1,82 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+
+char **av;
+
+void
+usage (char *s)
+{
+	fprintf (stderr, "Usage: %s [file]\n");
+}
+
+void
+process (FILE *f, char *name)
+{
+	int a;
+	int b;  /* lo */
+	int c;  /* hi */
+	int d;  /* code */
+
+	int i;
+	unsigned char data[8192];
+
+	for (i = 0; i < 8192; i++) {
+		data[i] = getc (f);
+	}
+
+	b = 0;
+	c = 0x20;
+	d = 255 - 0x8c;
+
+#define BC (256*c + b - 8192)
+
+loop:
+	a = data[BC];
+	a ^= d;
+	data[BC] = a;
+	d = (d + 1) & 0xff;
+	a = d;
+	a ^= c;
+	d = a;
+	b = (b + 1) & 0xff;
+	if (b != 0)
+		goto noinc;
+	c++;
+	a = c;
+	if (a == 0x40)
+		goto done;
+noinc:
+	goto loop;
+
+done:
+
+	for (i = 0; i < 8192; i++)
+		putchar (data[i]);
+}
+
+int
+main (int argc, char **argv)
+{
+	av = argv;
+
+	if (argc < 2) {
+		process (stdin, "standard input");
+	} else if (argc == 2) {
+		FILE *f = fopen (argv[1], "r");
+
+		if (f) {
+			process (f, argv[1]);
+			fclose (f);
+		} else {
+			fprintf (stderr, "%s: %s: %s\n", argv[0], argv[1],
+				 strerror (errno));
+			exit (EXIT_FAILURE);
+		}
+	} else {
+		usage (argv[0]);
+		exit (EXIT_FAILURE);
+	}
+
+	return (EXIT_SUCCESS);
+}