From 173e7486900b4fa0daf9653d55ad8ad2d461b8b8 Mon Sep 17 00:00:00 2001
From: zakihussain <85828740+zakihussain@users.noreply.github.com>
Date: Tue, 18 Nov 2025 10:13:22 +0500
Subject: [PATCH] Clear round keys before generating subkeys
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Before this change, each round's subkey could have leftover bits from the previous round because we didn’t clear key_sets[i].k. This could cause wrong keys during encryption. Now, we set all 8 bytes of the round key to 0 before generating it, which fixes a potential problem and makes subkey generation correct.
---
 des.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/des.c b/des.c
index ada929c..04285c8 100644
--- a/des.c
+++ b/des.c
@@ -150,8 +150,11 @@ void generate_sub_keys(unsigned char* main_key, key_set* key_sets) {
 	int shift_size;
 	unsigned char shift_byte, first_shift_bits, second_shift_bits, third_shift_bits, fourth_shift_bits;
 
-	for (i=0; i<8; i++) {
-		key_sets[0].k[i] = 0;
+	for (i = 1; i < 17; i++) {
+    // Initialize the round subkey to 0 before filling it
+    	for (int x = 0; x < 8; x++) {
+       		key_sets[i].k[x] = 0;
+    	}
 	}
 
 	for (i=0; i<56; i++) {