fix: qmc2_rc4 impl

um_crypto/qmc/src/v2_rc4/cipher.rs

@@ -31,7 +31,7 @@ impl QMC2RC4 {
         let n = self.key.len();
 
         for (value, offset) in dst.iter_mut().zip(offset..) {
-            let idx = get_segment_key(offset as u64, self.key[offset % n], self.hash);
+            let idx = get_segment_key(offset as u64, self.key[offset % n], self.hash) as usize;
             *value ^= self.key[idx % n];
         }
     }
@@ -42,10 +42,11 @@ impl QMC2RC4 {
         let id = offset / OTHER_SEGMENT_SIZE;
         let block_offset = offset % OTHER_SEGMENT_SIZE;
 
-        let skip = get_segment_key(id as u64, self.key[block_offset % n], self.hash);
+        let seed = self.key[id % n];
+        let skip = get_segment_key(id as u64, seed, self.hash) % 512;
 
         debug_assert!(data.len() <= OTHER_SEGMENT_SIZE - block_offset);
-        let key_stream = self.key_stream.iter().skip(skip + block_offset);
+        let key_stream = self.key_stream.iter().skip(skip as usize + block_offset);
         for (datum, &key) in data.iter_mut().zip(key_stream) {
             *datum ^= key;
         }
@@ -83,4 +84,42 @@ impl QMC2RC4 {
     }
 }
 
-// TODO: Add tests here
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_qmc2_header() {
+        let mut data = [
+            0x39, 0x5a, 0x4f, 0x75, 0x38, 0x71, 0x37, 0x6b, 0x36, 0x51, 0x53, 0x6d, 0x7a, 0x66,
+            0x53, 0x4b, 0x66, 0x50, 0x69, 0x34, 0x67, 0x6c, 0x33, 0x7a, 0x55, 0x62, 0x35, 0x5a,
+            0x32, 0x75, 0x4f, 0x68, 0x44, 0x52, 0x6d, 0x65, 0x75, 0x6e, 0x39, 0x52, 0x30, 0x7a,
+            0x68, 0x62, 0x73, 0x59, 0x39, 0x48, 0x55, 0x57, 0x73, 0x32, 0x5a, 0x70, 0x64, 0x50,
+            0x4e, 0x52, 0x6a, 0x63, 0x4d, 0x39, 0x37, 0x76, 0x72, 0x47, 0x64, 0x4d, 0x62, 0x6d,
+            0x58, 0x68, 0x75, 0x47, 0x37, 0x56, 0x69, 0x6b, 0x4a, 0x79, 0x66, 0x63, 0x70, 0x39,
+            0x59, 0x34, 0x43, 0x6b, 0x45, 0x32, 0x5a, 0x31, 0x38, 0x77, 0x70, 0x43, 0x51, 0x79,
+            0x6a, 0x62, 0x32, 0x33, 0x65, 0x58, 0x4a, 0x4d, 0x33, 0x4e, 0x70, 0x62, 0x62, 0x67,
+            0x4c, 0x54, 0x78, 0x64, 0x64, 0x77, 0x6e, 0x72, 0x37, 0x41, 0x54, 0x39, 0x42, 0x52,
+            0x47, 0x32, 0x1a, 0xe4, 0x1b, 0x71, 0x68, 0x29, 0xb3, 0x6e, 0xad, 0xc5, 0x28, 0x12,
+            0xd6, 0xa4, 0x4b, 0x06, 0x7a, 0xdc, 0x90, 0x15, 0x99, 0xd6, 0xbf, 0x72, 0xa2, 0x30,
+            0x37, 0x6b, 0x5c, 0xd6, 0x2f, 0x35, 0x14, 0x8a, 0xd6, 0xfb, 0x9f, 0xee, 0x7d, 0x2d,
+            0xb7, 0x37, 0xf2, 0x0b, 0x6e, 0x00, 0xfb, 0xa0, 0x3c, 0x40, 0xf3, 0x36, 0xb2, 0x76,
+            0x20, 0x0f, 0x9e, 0xa5, 0xa3, 0x15, 0x60, 0x23, 0x15, 0x29, 0xa1, 0x91, 0xbf, 0xfb,
+            0x12, 0x95, 0xaa, 0x8d, 0x92, 0xc6, 0x0b, 0x8d, 0x49, 0x99, 0xa5, 0xe0, 0x05, 0xcf,
+            0xb6, 0xac, 0x07, 0x54, 0x58, 0x28, 0xf9, 0x96, 0xd1, 0x9a, 0xfe, 0x0b, 0x3c, 0xfb,
+            0x0b, 0x25, 0x7a, 0x43, 0x5a, 0x33, 0xc3, 0x7a, 0xfc, 0x33, 0xa3, 0xc2, 0x65, 0x48,
+            0x29, 0x8d, 0x2c, 0x8f, 0x4e, 0x88, 0xfd, 0x44, 0xfd, 0xd5, 0xca, 0xb9, 0x8d, 0x62,
+            0x4a, 0x48, 0x20, 0x1du8,
+        ];
+        let key = (b'a'..=b'z')
+            .chain(b'A'..=b'Z')
+            .chain(b'0'..=b'9')
+            .cycle()
+            .take(512)
+            .collect::<Vec<u8>>();
+
+        let mut cipher = QMC2RC4::new(&key);
+        cipher.transform(0, &mut data);
+        assert_eq!(data, [0u8; 256]);
+    }
+}

um_crypto/qmc/src/v2_rc4/segment_key.rs

@@ -1,9 +1,9 @@
-pub fn get_segment_key(id: u64, seed: u8, hash: f64) -> usize {
+pub fn get_segment_key(id: u64, seed: u8, hash: f64) -> u32 {
     match seed {
         0 => 0,
         seed => {
             let result = hash / ((id + 1).wrapping_mul(seed.into()) as f64) * 100.0;
-            result as usize
+            result as u32
         }
     }
 }