diff --git a/NDecrypt.Core/CIATool.cs b/NDecrypt.Core/CIATool.cs
index a7ba60e..6cfcb36 100644
--- a/NDecrypt.Core/CIATool.cs
+++ b/NDecrypt.Core/CIATool.cs
@@ -295,7 +295,7 @@ namespace NDecrypt.Core
 
             // Create the ExeFS AES cipher for this partition
             int ctroffsetE = (int)(mediaUnitSize / 0x10);
-            byte[] exefsIVWithOffset = AddToByteArray(header.ExeFSIV(), ctroffsetE);
+            byte[] exefsIVWithOffset = Add(header.ExeFSIV(), ctroffsetE);
             var cipher = CreateAESDecryptionCipher(KeysMap[index].NormalKey2C, exefsIVWithOffset);
 
             // Setup and perform the decryption
@@ -393,7 +393,7 @@ namespace NDecrypt.Core
 
                 // Create the ExeFS AES ciphers for this partition
                 uint ctroffset = (fileHeader.FileOffset + mediaUnitSize) / 0x10;
-                byte[] exefsIVWithOffsetForHeader = AddToByteArray(header.ExeFSIV(), (int)ctroffset);
+                byte[] exefsIVWithOffsetForHeader = Add(header.ExeFSIV(), (int)ctroffset);
                 var firstCipher = CreateAESDecryptionCipher(KeysMap[index].NormalKey, exefsIVWithOffsetForHeader);
                 var secondCipher = CreateAESEncryptionCipher(KeysMap[index].NormalKey2C, exefsIVWithOffsetForHeader);
 
@@ -684,7 +684,7 @@ namespace NDecrypt.Core
 
             // Create the ExeFS AES cipher for this partition
             int ctroffsetE = (int)(mediaUnitSize / 0x10);
-            byte[] exefsIVWithOffset = AddToByteArray(header.ExeFSIV(), ctroffsetE);
+            byte[] exefsIVWithOffset = Add(header.ExeFSIV(), ctroffsetE);
             var cipher = CreateAESEncryptionCipher(KeysMap[index].NormalKey2C, exefsIVWithOffset);
 
             // Setup and perform the decryption
@@ -782,7 +782,7 @@ namespace NDecrypt.Core
 
                 // Create the ExeFS AES ciphers for this partition
                 uint ctroffset = (fileHeader.FileOffset + mediaUnitSize) / 0x10;
-                byte[] exefsIVWithOffsetForHeader = AddToByteArray(header.ExeFSIV(), (int)ctroffset);
+                byte[] exefsIVWithOffsetForHeader = Add(header.ExeFSIV(), (int)ctroffset);
                 var firstCipher = CreateAESEncryptionCipher(KeysMap[index].NormalKey, exefsIVWithOffsetForHeader);
                 var secondCipher = CreateAESDecryptionCipher(KeysMap[index].NormalKey2C, exefsIVWithOffsetForHeader);
 
diff --git a/NDecrypt.Core/CommonOperations.cs b/NDecrypt.Core/CommonOperations.cs
index 2ed107d..7845565 100644
--- a/NDecrypt.Core/CommonOperations.cs
+++ b/NDecrypt.Core/CommonOperations.cs
@@ -9,7 +9,7 @@ using SabreTools.Models.N3DS;
 
 namespace NDecrypt.Core
 {
-    internal static class CommonOperations
+    public static class CommonOperations
     {
         #region AES
 
@@ -167,7 +167,7 @@ namespace NDecrypt.Core
         /// <param name="input">Byte array to add to</param>
         /// <param name="add">Amount to add</param>
         /// <returns>Byte array representing the new value</returns>
-        public static byte[] AddToByteArray(byte[] input, int add)
+        public static byte[] Add(byte[] input, int add)
         {
             int len = input.Length;
             Array.Reverse(input);
@@ -190,6 +190,35 @@ namespace NDecrypt.Core
             return arr;
         }
 
+        /// <summary>
+        /// Add two numbers represented by byte arrays
+        /// </summary>
+        /// <param name="left">Byte array to add to</param>
+        /// <param name="right">Amount to add</param>
+        /// <returns>Byte array representing the new value</returns>
+        public static byte[] Add(byte[] left, byte[] right)
+        {
+            int addBytes = Math.Min(left.Length, right.Length);
+            int outLength = Math.Max(left.Length, right.Length);
+
+            byte[] output = new byte[outLength];
+
+            int carry = 0;
+            for (int i = 0; i < addBytes; i++)
+            {
+                int addValue = left[i] + right[i] + carry;
+                output[i] = (byte)addValue;
+                carry = addValue > byte.MaxValue ? byte.MaxValue - addValue : 0;
+            }
+
+            if (outLength != addBytes && left.Length == outLength)
+                Array.Copy(left, addBytes, output, addBytes, outLength - addBytes);
+            else if (outLength != addBytes && right.Length == outLength)
+                Array.Copy(right, addBytes, output, addBytes, outLength - addBytes);
+
+            return output;
+        }
+
         /// <summary>
         /// Perform a rotate left on a BigInteger
         /// </summary>
@@ -202,6 +231,69 @@ namespace NDecrypt.Core
             return (val << r_bits % max_bits) & (BigInteger.Pow(2, max_bits) - 1) | ((val & (BigInteger.Pow(2, max_bits) - 1)) >> (max_bits - (r_bits % max_bits)));
         }
 
+        /// <summary>
+        /// Perform a rotate left on a byte array
+        /// </summary>
+        /// <param name="val">Byte array value to rotate</param>
+        /// <param name="r_bits">Number of bits to rotate</param>
+        /// <returns>Rotated byte array value</returns>
+        public static byte[] RotateLeft(byte[] val, int r_bits)
+        {
+            // Shift by bytes
+            while (r_bits >= 8)
+            {
+                byte temp = val[0];
+                for (int i = 0; i < val.Length - 1; i++)
+                {
+                    val[i] = val[i + 1];
+                }
+
+                val[val.Length - 1] = temp;
+                r_bits -= 8;
+            }
+
+            // Shift by bits
+            while (r_bits-- > 0)
+            {
+                int carry = 0;
+                for (int i = 0; i < val.Length; i++)
+                {
+                    byte nextByte = (byte)((val[i] << 1) + carry);
+                    carry = (val[i] << 1) > byte.MaxValue ? byte.MaxValue - (val[i] << 1) : 0;
+                    val[i] = nextByte;
+                }
+
+                val[val.Length - 1] = (byte)(val[val.Length - 1] + carry);
+            }
+
+            return val;
+        }
+
+        /// <summary>
+        /// XOR two numbers represented by byte arrays
+        /// </summary>
+        /// <param name="left">Byte array to XOR to</param>
+        /// <param name="right">Amount to XOR</param>
+        /// <returns>Byte array representing the new value</returns>
+        public static byte[] Xor(byte[] left, byte[] right)
+        {
+            int xorBytes = Math.Min(left.Length, right.Length);
+            int outLength = Math.Max(left.Length, right.Length);
+
+            byte[] output = new byte[outLength];
+            for (int i = 0; i < xorBytes; i++)
+            {
+                output[i] = (byte)(left[i] ^ right[i]);
+            }
+
+            if (outLength != xorBytes && left.Length == outLength)
+                Array.Copy(left, xorBytes, output, xorBytes, outLength - xorBytes);
+            else if (outLength != xorBytes && right.Length == outLength)
+                Array.Copy(right, xorBytes, output, xorBytes, outLength - xorBytes);
+
+            return output;
+        }
+
         #endregion
 
         #region Offsets
diff --git a/NDecrypt.Core/ThreeDSTool.cs b/NDecrypt.Core/ThreeDSTool.cs
index c1b975b..fc45c06 100644
--- a/NDecrypt.Core/ThreeDSTool.cs
+++ b/NDecrypt.Core/ThreeDSTool.cs
@@ -283,7 +283,7 @@ namespace NDecrypt.Core
 
             // Create the ExeFS AES cipher for this partition
             int ctroffsetE = (int)(cart.MediaUnitSize() / 0x10);
-            byte[] exefsIVWithOffset = AddToByteArray(cart.ExeFSIV(index), ctroffsetE);
+            byte[] exefsIVWithOffset = Add(cart.ExeFSIV(index), ctroffsetE);
             var cipher = CreateAESDecryptionCipher(KeysMap[index].NormalKey2C, exefsIVWithOffset);
 
             // Setup and perform the decryption
@@ -369,7 +369,7 @@ namespace NDecrypt.Core
 
                 // Create the ExeFS AES ciphers for this partition
                 uint ctroffset = (fileHeader.FileOffset + cart.MediaUnitSize()) / 0x10;
-                byte[] exefsIVWithOffsetForHeader = AddToByteArray(cart.ExeFSIV(index), (int)ctroffset);
+                byte[] exefsIVWithOffsetForHeader = Add(cart.ExeFSIV(index), (int)ctroffset);
                 var firstCipher = CreateAESDecryptionCipher(KeysMap[index].NormalKey, exefsIVWithOffsetForHeader);
                 var secondCipher = CreateAESEncryptionCipher(KeysMap[index].NormalKey2C, exefsIVWithOffsetForHeader);
 
@@ -643,7 +643,7 @@ namespace NDecrypt.Core
 
             // Create the ExeFS AES cipher for this partition
             int ctroffsetE = (int)(cart.MediaUnitSize() / 0x10);
-            byte[] exefsIVWithOffset = AddToByteArray(cart.ExeFSIV(index), ctroffsetE);
+            byte[] exefsIVWithOffset = Add(cart.ExeFSIV(index), ctroffsetE);
             var cipher = CreateAESEncryptionCipher(KeysMap[index].NormalKey2C, exefsIVWithOffset);
 
             // Setup and perform the encryption
@@ -729,7 +729,7 @@ namespace NDecrypt.Core
 
                 // Create the ExeFS AES ciphers for this partition
                 uint ctroffset = (fileHeader.FileOffset + cart.MediaUnitSize()) / 0x10;
-                byte[] exefsIVWithOffsetForHeader = AddToByteArray(cart.ExeFSIV(index), (int)ctroffset);
+                byte[] exefsIVWithOffsetForHeader = Add(cart.ExeFSIV(index), (int)ctroffset);
                 var firstCipher = CreateAESEncryptionCipher(KeysMap[index].NormalKey, exefsIVWithOffsetForHeader);
                 var secondCipher = CreateAESDecryptionCipher(KeysMap[index].NormalKey2C, exefsIVWithOffsetForHeader);
 
diff --git a/NDecrypt/Program.cs b/NDecrypt/Program.cs
index cf10c7b..b08aea7 100644
--- a/NDecrypt/Program.cs
+++ b/NDecrypt/Program.cs
@@ -14,6 +14,18 @@ namespace NDecrypt
 
         public static void Main(string[] args)
         {
+            // TEMP SHIT CODE
+
+            byte[] x =
+            [
+                0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+                0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F,
+            ];
+            x = CommonOperations.Add(x, x);
+            string s = BitConverter.ToString(x);
+
+            // END TEMP SHIT CODE
+
             if (args.Length < 2)
             {
                 DisplayHelp("Not enough arguments");