diff --git a/src/aeslua.lua b/src/aeslua.lua
index a18573e..8bd77f5 100644
--- a/src/aeslua.lua
+++ b/src/aeslua.lua
@@ -48,10 +48,11 @@ end
 -- data      - string to encrypt (must not be too large)
 -- keyLength - length of aes key: 128(default), 192 or 256 Bit
 -- mode      - mode of encryption: ecb, cbc(default), ofb, cfb 
+-- iv        - initialization vector to use
 --
 -- mode and keyLength must be the same for encryption and decryption.
 --
-function public.encrypt(password, data, keyLength, mode)
+function public.encrypt(password, data, keyLength, mode, iv)
 	assert(password ~= nil, "Empty password.");
 	assert(password ~= nil, "Empty data.");
 	 
@@ -63,13 +64,13 @@ function public.encrypt(password, data, keyLength, mode)
     local paddedData = util.padByteString(data);
     
     if (mode == public.ECBMODE) then
-        return ciphermode.encryptString(key, paddedData, ciphermode.encryptECB);
+        return ciphermode.encryptString(key, paddedData, ciphermode.encryptECB, iv);
     elseif (mode == public.CBCMODE) then
-        return ciphermode.encryptString(key, paddedData, ciphermode.encryptCBC);
+        return ciphermode.encryptString(key, paddedData, ciphermode.encryptCBC, iv);
     elseif (mode == public.OFBMODE) then
-        return ciphermode.encryptString(key, paddedData, ciphermode.encryptOFB);
+        return ciphermode.encryptString(key, paddedData, ciphermode.encryptOFB, iv);
     elseif (mode == public.CFBMODE) then
-        return ciphermode.encryptString(key, paddedData, ciphermode.encryptCFB);
+        return ciphermode.encryptString(key, paddedData, ciphermode.encryptCFB, iv);
     else
         return nil;
     end
@@ -84,10 +85,11 @@ end
 -- data      - string to encrypt
 -- keyLength - length of aes key: 128(default), 192 or 256 Bit
 -- mode      - mode of decryption: ecb, cbc(default), ofb, cfb 
+-- iv        - initialization vector to use
 --
 -- mode and keyLength must be the same for encryption and decryption.
 --
-function public.decrypt(password, data, keyLength, mode)
+function public.decrypt(password, data, keyLength, mode, iv)
     local mode = mode or public.CBCMODE;
     local keyLength = keyLength or public.AES128;
 
@@ -95,13 +97,13 @@ function public.decrypt(password, data, keyLength, mode)
     
     local plain;
     if (mode == public.ECBMODE) then
-        plain = ciphermode.decryptString(key, data, ciphermode.decryptECB);
+        plain = ciphermode.decryptString(key, data, ciphermode.decryptECB, iv);
     elseif (mode == public.CBCMODE) then
-        plain = ciphermode.decryptString(key, data, ciphermode.decryptCBC);
+        plain = ciphermode.decryptString(key, data, ciphermode.decryptCBC, iv);
     elseif (mode == public.OFBMODE) then
-        plain = ciphermode.decryptString(key, data, ciphermode.decryptOFB);
+        plain = ciphermode.decryptString(key, data, ciphermode.decryptOFB, iv);
     elseif (mode == public.CFBMODE) then
-        plain = ciphermode.decryptString(key, data, ciphermode.decryptCFB);
+        plain = ciphermode.decryptString(key, data, ciphermode.decryptCFB, iv);
     end
     
     result = util.unpadByteString(plain);
diff --git a/src/aeslua/ciphermode.lua b/src/aeslua/ciphermode.lua
index ab1faf1..b247f36 100644
--- a/src/aeslua/ciphermode.lua
+++ b/src/aeslua/ciphermode.lua
@@ -11,8 +11,9 @@ aeslua.ciphermode = public;
 -- key - byte array with key
 -- string - string to encrypt
 -- modefunction - function for cipher mode to use
+-- iv - initialization vector to use
 --
-function public.encryptString(key, data, modeFunction)
+function public.encryptString(key, data, modeFunction, iv)
     local iv = iv or {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();
@@ -71,8 +72,9 @@ end
 -- key - byte array with key
 -- string - string to decrypt
 -- modefunction - function for cipher mode to use
+-- iv - initialization vector to use
 --
-function public.decryptString(key, data, modeFunction)
+function public.decryptString(key, data, modeFunction, iv)
     local iv = iv or {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
     
     local keySched;