Diff: cipher/RC4.cpp

Revision:

7:2dbbdfb08123

Parent:

0:7a1237bd2d13

Child:

8:a090264e9b2d

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cipher/RC4.cpp	Sat Sep 14 18:21:32 2013 +0000
@@ -0,0 +1,46 @@
+#include "RC4.h"
+
+RC4::RC4(uint8_t *key, uint8_t keyLength):
+Cipher(),
+s(),
+i(0),
+j(0)
+{
+    for(int k = 0; k < 256; ++k)
+        s[k] = k;
+    int l = 0;
+    for(int k = 0; k < 256; ++k)
+    {
+        l = (l + s[k] + key[k % keyLength]) % 256;
+        uint8_t tmp = s[l];
+        s[l] = s[k];
+        s[k] = tmp;
+    } 
+}
+
+uint8_t RC4::encyptByte(uint8_t in)
+{
+    ++i;
+    j += s[i];
+    uint8_t tmp = s[i];
+    s[i] = s[j];
+    s[j] = tmp;
+    uint8_t c = s[(s[i]+s[j])%256];
+    return in^c;
+}
+
+void RC4::encrypt(uint8_t *out, uint8_t *in, uint32_t length)
+{
+    for(uint32_t l = 0; l < length; ++l)
+        out[l] = encyptByte(in[l]);
+}
+
+void RC4::decrypt(uint8_t *out, uint8_t *in, uint32_t length)    
+{
+    encrypt(out, in, length);
+}
+
+uint32_t RC4::getBlockSize() const
+{
+    return 1;
+}