--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/aeslua/ciphermode.lua Wed Feb 16 20:29:33 2011 +0000
@@ -0,0 +1,148 @@
+local aes = require("aeslua.aes");
+local util = require("aeslua.util");
+local buffer = require("aeslua.buffer");
+
+local public = {};
+
+local aeslua = require("aeslua");
+aeslua.ciphermode = public;
+
+--
+-- Encrypt strings
+-- key - byte array with key
+-- string - string to encrypt
+-- modefunction - function for cipher mode to use
+--
+function public.encryptString(key, data, modeFunction)
+ local iv = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
+ local keySched = aes.expandEncryptionKey(key);
+ local encryptedData = buffer.new();
+
+ for i = 1, #data/16 do
+ local offset = (i-1)*16 + 1;
+ local byteData = {string.byte(data,offset,offset +15)};
+
+ modeFunction(keySched, byteData, iv);
+
+ buffer.addString(encryptedData, string.char(unpack(byteData)));
+ end
+
+ return buffer.toString(encryptedData);
+end
+
+--
+-- the following 4 functions can be used as
+-- modefunction for encryptString
+--
+
+-- Electronic code book mode encrypt function
+function public.encryptECB(keySched, byteData, iv)
+ aes.encrypt(keySched, byteData, 1, byteData, 1);
+end
+
+-- Cipher block chaining mode encrypt function
+function public.encryptCBC(keySched, byteData, iv)
+ util.xorIV(byteData, iv);
+
+ aes.encrypt(keySched, byteData, 1, byteData, 1);
+
+ for j = 1,16 do
+ iv[j] = byteData[j];
+ end
+end
+
+-- Output feedback mode encrypt function
+function public.encryptOFB(keySched, byteData, iv)
+ aes.encrypt(keySched, iv, 1, iv, 1);
+ util.xorIV(byteData, iv);
+end
+
+-- Cipher feedback mode encrypt function
+function public.encryptCFB(keySched, byteData, iv)
+ aes.encrypt(keySched, iv, 1, iv, 1);
+ util.xorIV(byteData, iv);
+
+ for j = 1,16 do
+ iv[j] = byteData[j];
+ end
+end
+
+--
+-- Decrypt strings
+-- key - byte array with key
+-- string - string to decrypt
+-- modefunction - function for cipher mode to use
+--
+function public.decryptString(key, data, modeFunction)
+ local iv = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
+
+ local keySched;
+ if (modeFunction == public.decryptOFB or modeFunction == public.decryptCFB) then
+ keySched = aes.expandEncryptionKey(key);
+ else
+ keySched = aes.expandDecryptionKey(key);
+ end
+
+ local decryptedData = buffer.new();
+
+ for i = 1, #data/16 do
+ local offset = (i-1)*16 + 1;
+ local byteData = {string.byte(data,offset,offset +15)};
+
+ iv = modeFunction(keySched, byteData, iv);
+
+ buffer.addString(decryptedData, string.char(unpack(byteData)));
+ end
+
+ return buffer.toString(decryptedData);
+end
+
+--
+-- the following 4 functions can be used as
+-- modefunction for decryptString
+--
+
+-- Electronic code book mode decrypt function
+function public.decryptECB(keySched, byteData, iv)
+
+ aes.decrypt(keySched, byteData, 1, byteData, 1);
+
+ return iv;
+end
+
+-- Cipher block chaining mode decrypt function
+function public.decryptCBC(keySched, byteData, iv)
+ local nextIV = {};
+ for j = 1,16 do
+ nextIV[j] = byteData[j];
+ end
+
+ aes.decrypt(keySched, byteData, 1, byteData, 1);
+ util.xorIV(byteData, iv);
+
+ return nextIV;
+end
+
+-- Output feedback mode decrypt function
+function public.decryptOFB(keySched, byteData, iv)
+ aes.encrypt(keySched, iv, 1, iv, 1);
+ util.xorIV(byteData, iv);
+
+ return iv;
+end
+
+-- Cipher feedback mode decrypt function
+function public.decryptCFB(keySched, byteData, iv)
+ local nextIV = {};
+ for j = 1,16 do
+ nextIV[j] = byteData[j];
+ end
+
+ aes.encrypt(keySched, iv, 1, iv, 1);
+
+ util.xorIV(byteData, iv);
+
+ return nextIV;
+end
+
+return public;