From 0bcd78be9657f35dd27a02c16cb70234b1e44d5b Mon Sep 17 00:00:00 2001
From: n0p <0x90@n0p.cc>
Date: Mon, 27 Oct 2014 19:07:43 +0100
Subject: Reversing challenge 300 from hack.lu 2014.

---
 src/desCalculator/desCalculator.c | 54 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 src/desCalculator/desCalculator.c

(limited to 'src/desCalculator/desCalculator.c')

diff --git a/src/desCalculator/desCalculator.c b/src/desCalculator/desCalculator.c
new file mode 100644
index 0000000..a6f1dba
--- /dev/null
+++ b/src/desCalculator/desCalculator.c
@@ -0,0 +1,54 @@
+#include <stdio.h>
+#include <stdint.h>
+#include "des.h"
+
+int main()
+{
+	char *keyword;
+	unsigned char plaintext[16];
+	unsigned char ciphertext[16];
+	int j;
+	DES_KEY key;
+	uint32_t AddressOfEntryPoint = 0x00002140;
+
+	keyword = (char *)calloc(8, 1);
+	if (keyword == NULL)
+		return -1;
+
+	for (j = 0; j < 8; j++) {
+		// The key goes here
+		keyword[j] = '\x7f';
+	}
+
+	*(uint32_t *)keyword ^= 0x41424344;
+	*((uint32_t *)keyword + 1) ^= AddressOfEntryPoint;
+
+	/* Authentication: DEAD696E18791211 => 0xDEAD in 0x1879 0x1 ! 0x1 */
+	plaintext[0] = '\xDE';
+	plaintext[1] = '\xAD';
+	plaintext[2] = '\x69';
+	plaintext[3] = '\x6E';
+	plaintext[4] = '\x18';
+	plaintext[5] = '\x79';
+	plaintext[6] = '\x12';
+	plaintext[7] = '\x11';
+
+	memcpy(ciphertext, plaintext, 8);
+
+	_mcrypt_set_key(&key, (void *) keyword, 8);
+	free(keyword);
+
+	_mcrypt_encrypt(&key, (void *) ciphertext);
+
+
+	printf("des_output_value = [0x%02X",ciphertext[3]);
+	printf("%02X",ciphertext[2]);
+	printf("%02X",ciphertext[1]);
+	printf("%02X, ",ciphertext[0]);
+	printf("0x%02X",ciphertext[7]);
+	printf("%02X",ciphertext[6]);
+	printf("%02X",ciphertext[5]);
+	printf("%02X]",ciphertext[4]);
+
+	return 0;
+}
\ No newline at end of file
-- 
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