From 6f16487641aa1118da1fede9eff9c9b812eb358c Mon Sep 17 00:00:00 2001
From: PlexSheep <PlexSheep@protonmail.com>
Date: Wed, 10 May 2023 15:36:50 +0200
Subject: [PATCH] between

---
 src/algo/feistel0.rs | 46 ++++++++++++++++++++++++++++++++++++++------
 1 file changed, 40 insertions(+), 6 deletions(-)

diff --git a/src/algo/feistel0.rs b/src/algo/feistel0.rs
index 1e0266d..7901704 100644
--- a/src/algo/feistel0.rs
+++ b/src/algo/feistel0.rs
@@ -8,16 +8,50 @@
 /// License:    MIT
 /// Source:     <https://git.cscherr.de/PlexSheep/plexcryptool/>
 
+const SBOX: [u8; 0x10] = [0x4, 3, 9, 0xa, 0xb, 2, 0xe, 1, 0xd, 0xc, 8, 6, 7, 5, 0, 0xf];
+
+fn swap_bits(n: u8, p1: u8, p2: u8) -> u8 {
+    let bit1 = (n >> p1) & 1;
+    let bit2 = (n >> p2) & 1;
+    let mut x = (bit1 ^ bit2);
+    x = (x << p1) | (x << p2);
+ 
+    n ^ x
+}
 
 pub fn inner(input: u16, key: u16) -> u16 {
-    let blocks = [
-        input & 0xf000, 
-        input & 0x0f00, 
-        input & 0x00f0,
-        input & 0x000f,
+    // cut into u8 blocks
+    let mut blocks: [u8; 4] = [
+        ((input & 0xf000) >> 12).to_be_bytes()[1],
+        ((input & 0x0f00) >> 08).to_be_bytes()[1],
+        ((input & 0x000f) >> 00).to_be_bytes()[1],
+        ((input & 0x00f0) >> 04).to_be_bytes()[1],
     ];
-    dbg!(blocks);
 
+    dbg!(&blocks);
+
+    // each block must not be more than 0xf
+    for block in blocks {
+        if block > 0xf {
+            panic!("Block is more than 0xf: {block}");
+        }
+    }
+
+    // inner blocks into sbox
+    blocks[1] = SBOX[blocks[1] as usize];
+    blocks[2] = SBOX[blocks[2] as usize];
+
+    dbg!(&blocks);
+
+    // swap position and endianess for outer blocks
+    let tmp = blocks[0];
+    blocks[0] = u8::swap_bytes(blocks[3]);
+    blocks[3] = u8::swap_bytes(tmp);
+
+    dbg!(&blocks);
+    
+    println!("{:04b} {:04b} {:04b} {:04b}", blocks[0], blocks[1], blocks[2], blocks[3]);
+    println!("{:x}{:x}{:x}{:x}", blocks[0], blocks[1], blocks[2], blocks[3]);
 
     panic!("Not implemented");
 }