Let us start here, from square one. No, from Zero!

2022-09-30 22:45:51 +09:00
parent 14215af0d1
commit b7a60638a4
1005 changed files with 303069 additions and 0 deletions
@@ -0,0 +1,48 @@
+part of spiceapi;
+
+class RC4 {
+
+  // state
+  int _a = 0;
+  int _b = 0;
+  List<int> _sBox = List<int>(256);
+
+  RC4(List<int> key) {
+
+    // init sBox
+    for (int i = 0; i < 256; i++) {
+      _sBox[i] = i;
+    }
+
+    // process key
+    int j = 0;
+    for (int i = 0; i < 256; i++) {
+
+      // update
+      j = (j + _sBox[i] + key[i % key.length]) % 256;
+
+      // swap
+      var tmp = _sBox[i];
+      _sBox[i] = _sBox[j];
+      _sBox[j] = tmp;
+    }
+  }
+
+  void crypt(List<int> inData) {
+    for (int i = 0; i < inData.length; i++) {
+
+      // update
+      _a = (_a + 1) % 256;
+      _b = (_b + _sBox[_a]) % 256;
+
+      // swap
+      var tmp = _sBox[_a];
+      _sBox[_a] = _sBox[_b];
+      _sBox[_b] =  tmp;
+
+      // crypt
+      inData[i] ^= _sBox[(_sBox[_a] + _sBox[_b]) % 256];
+    }
+  }
+
+}