public void AES_ECB_decrypt(ref AES_ctx ctx, ref uint[] buf)
{
// The next function call decrypts the PlainText with the Key using AES algorithm.
uint k = 0;
Array.Clear(state_t.state_t, 0, 16);
for (int j = 0; j < 4 && k < buf.Length; j++)
{
for (int i = 0; i < 4 && k < buf.Length; i++, k++)
{
state_t.state_t[j, i] = buf[k];
}
}
InvCipher(ref state_t, ref ctx.RoundKey);
}
void AES_ctx_set_iv(ref AES_ctx ctx, ref uint[] iv)
{
Array.Copy(ctx.Iv, iv, AES_BLOCKLEN);
}
void AES_init_ctx_iv(ref AES_ctx ctx, ref uint[] key, ref uint[] iv)
{
KeyExpansion(ref ctx, ref key);
Array.Copy(iv, ctx.Iv, AES_BLOCKLEN);
}
public void AES_init_ctx(ref AES_ctx ctx, ref uint[] key)
{
KeyExpansion(ref ctx, ref key);
}
// This function produces Nb(Nr+1) round keys. The round keys are used in each round to decrypt the states.
private void KeyExpansion(ref AES_ctx RoundKey, ref uint[] Key)
{
uint i, j, k;
uint[] tempa = new uint[4]; // Used for the column/row operations
// The first round key is the key itself.
for (i = 0; i < Nk; ++i)
{
RoundKey.RoundKey[(i * 4) + 0] = Key[(i * 4) + 0];
RoundKey.RoundKey[(i * 4) + 1] = Key[(i * 4) + 1];
RoundKey.RoundKey[(i * 4) + 2] = Key[(i * 4) + 2];
RoundKey.RoundKey[(i * 4) + 3] = Key[(i * 4) + 3];
}
// All other round keys are found from the previous round keys.
for (i = Nk; i < Nb * (Nr + 1); ++i)
{
{
k = (i - 1) * 4;
tempa[0] = RoundKey.RoundKey[k + 0];
tempa[1] = RoundKey.RoundKey[k + 1];
tempa[2] = RoundKey.RoundKey[k + 2];
tempa[3] = RoundKey.RoundKey[k + 3];
}
if (i % Nk == 0)
{
// This function shifts the 4 bytes in a word to the left once.
// [a0,a1,a2,a3] becomes [a1,a2,a3,a0]
// Function RotWord()
{
k = tempa[0];
tempa[0] = tempa[1];
tempa[1] = tempa[2];
tempa[2] = tempa[3];
tempa[3] = k;
}
// SubWord() is a function that takes a four-byte input word and
// applies the S-box to each of the four bytes to produce an output word.
// Function Subword()
{
tempa[0] = getSBoxValue(tempa[0]);
tempa[1] = getSBoxValue(tempa[1]);
tempa[2] = getSBoxValue(tempa[2]);
tempa[3] = getSBoxValue(tempa[3]);
}
tempa[0] = tempa[0] ^ Rcon[i / Nk];
}
#if AES256
if (i % Nk == 4)
{
// Function Subword()
{
tempa[0] = getSBoxValue(tempa[0]);
tempa[1] = getSBoxValue(tempa[1]);
tempa[2] = getSBoxValue(tempa[2]);
tempa[3] = getSBoxValue(tempa[3]);
}
}
#endif
j = i * 4; k = (i - Nk) * 4;
RoundKey.RoundKey[j + 0] = RoundKey.RoundKey[k + 0] ^ tempa[0];
RoundKey.RoundKey[j + 1] = RoundKey.RoundKey[k + 1] ^ tempa[1];
RoundKey.RoundKey[j + 2] = RoundKey.RoundKey[k + 2] ^ tempa[2];
RoundKey.RoundKey[j + 3] = RoundKey.RoundKey[k + 3] ^ tempa[3];
}
}
public void EncryptFile(string inputFilename, string outputFilename, string firmwareRevisionFilename, string newKey)
{
Aes aes = new Aes();
if (!File.Exists(inputFilename))
{
Console.WriteLine("{0} {1}", inputFilename, " file does not exist!");
return;
}
if (File.Exists(outputFilename))
{
File.Delete(outputFilename);
}
if (firmwareRevisionFilename != "")
{
string revisionName = "";
revisionName = GetVersionNumberFromFile(firmwareRevisionFilename);
if (outputFilename.Contains(".crx"))
{
outputFilename = outputFilename.Insert(outputFilename.IndexOf(".crx"), "_" + revisionName + "_");
}
else
{
Console.WriteLine("The output file name extension is not valid. The extension should end in \".crx\"");
return;
}
}
FileStream fsOut = File.Create(outputFilename);
FileStream fsIn = File.OpenRead(inputFilename);
StreamReader sr = new StreamReader(fsIn);
ulong fileSize = (ulong)fsIn.Length;
// todo: final filesize. Needs to be in increments of 16 bytes.
ulong finalRemainder = (16 - (fileSize % 16)); // find how many bytes left then subtract from 16 to get value to add to current file size.
fileSize += finalRemainder; // add how many bytes to current file size
UInt16 lastKeys = (UInt16)(fileSize); // now get the low 2 byte value from fize size.
// Create your own 128 bit key. This should be the same key as the decryption key
uint[] key = new uint[16] {
0xA4, 0xDD, 0xE2, 0x16, 0x63, 0x51, 0x4A, 0x4D, 0xB1, 0xAB, 0x0E, 0x5D, 0x2C, 0xE2, 0xD7, 0xB7
}; // new guid (A4DDE216-6351-4A4D-B1AB-0E5D2CE2D7B7)
if (!newKey.Equals("")) // if a GUID was included then replace default GUID. Also I do not have error checking implemeted so an invalid GUID will more than likely cause a crash.
{
newKey = newKey.Replace("-", ""); // some GUId may have dashes, so this will remove them.
byte[] aKey = StrToByteArray(newKey);
Array.Copy(aKey, key, key.Length);
}
// changing last two bytes of key depending on file size. Doing this will make the encryption key random for each hex file.
key[14] = (uint)lastKeys >> 8;
key[15] = (uint)lastKeys & 0xff;
string getLine = string.Empty;
string temp_line = string.Empty;
AES_ctx ctx = new AES_ctx();
aes.AES_init_ctx(ref ctx, ref key);
char[] charArray = new char[fileSize];
//read all chars from file into array
for (ulong i = 0; i < fileSize; i++)
{
charArray[i] = (char)sr.Read();
}
uint[] tempArray = new uint[16]; // new array
ulong charCounter = 0;
while (charCounter < fileSize)
{
Array.Clear(tempArray, 0, tempArray.Length);
Array.Copy(charArray, (int)charCounter, tempArray, 0, 16);
aes.AES_ECB_encrypt(ref ctx, ref tempArray);
byte[] byteArray = new byte[16];
uint k = 0;
for (int j = 0; j < 4; j++)
{
for (uint i = 0; i < 4; i++, k++)
{
byteArray[k] = (byte)aes.state_t.state_t[j, i];
}
}
// write to the new file
fsOut.Write(byteArray, 0, byteArray.Length);
charCounter += 16;
}
fsIn.Close();
fsOut.Close();
Console.WriteLine(Path.GetFileName(inputFilename) + " has been encrypted successfully! New filename: " + Path.GetFileName(outputFilename));
}
public void DecryptFile(string inputFilename, string outputFilename, string newKey)
{
Aes aes = new Aes();
if (!File.Exists(inputFilename))
{
Console.WriteLine("{0} {1}", inputFilename, " file does not exist!");
return;
}
if (File.Exists(outputFilename))
{
File.Delete(outputFilename);
}
FileStream fsOut = File.Create(outputFilename);
FileStream fsIn = File.OpenRead(inputFilename);
StreamReader sr = new StreamReader(fsIn);
ulong fileSize = (ulong)fsIn.Length;
string myFile = string.Empty;
// Create your own 128 bit key. This should be the same as the encryption key
uint[] key = new uint[16] {
0xA4, 0xDD, 0xE2, 0x16, 0x63, 0x51, 0x4A, 0x4D, 0xB1, 0xAB, 0x0E, 0x5D, 0x2C, 0xE2, 0xD7, 0xB7
}; // new guid (A4DDE216-6351-4A4D-B1AB-0E5D2CE2D7B7)
if (!newKey.Equals(""))
{
newKey = newKey.Replace("-", "");
byte[] aKey = StrToByteArray(newKey);
Array.Copy(aKey, key, key.Length);
}
UInt16 lastKeys = (UInt16)(fileSize);
key[14] = (uint)lastKeys >> 8;
key[15] = (uint)lastKeys & 0xff; // changing last two bytes of key depending on file size.
//aes.Phex(ref key, 0);
byte[] fileBytes = new byte[fsIn.Length];
int numBytesToRead = (int)fsIn.Length;
int numBytesRead = 0;
while (numBytesToRead > 0)
{
// Read may return anything from 0 to numBytesToRead.
int n = fsIn.Read(fileBytes, numBytesRead, numBytesToRead);
// Break when the end of the file is reached.
if (n == 0)
{
break;
}
numBytesRead += n;
numBytesToRead -= n;
}
numBytesToRead = fileBytes.Length; // reload size
fsIn.Close(); // done with file
AES_ctx ctx = new AES_ctx();
aes.AES_init_ctx(ref ctx, ref key);
numBytesRead = 0;
while (numBytesRead < numBytesToRead)
{
uint[] tempArray = new uint[16]; // new temp array
Array.Copy(fileBytes, numBytesRead, tempArray, 0, 16); // copy 16 bytes at a time
aes.AES_ECB_decrypt(ref ctx, ref tempArray); // decrypt 16 bytes
byte[] byteArray = new byte[16];
Array.Clear(byteArray, 0, byteArray.Length);
uint k = 0;
for (int j = 0; j < 4; j++)
{
for (uint i = 0; i < 4; i++, k++)
{
byteArray[k] = (byte)((char)aes.state_t.state_t[j, i]);
}
}
myFile += Encoding.Default.GetString(byteArray); // keep adding to string
numBytesRead += 16; // inc the read pointer
}
byte myByte = 0;
numBytesRead = 0; // the counter for the file size
foreach (char c in myFile)
{
myByte = (byte)Convert.ToByte(c);
if (myByte <= 127) // check if ascii char 0-127
{
fsOut.WriteByte(myByte); // write whole string to file
numBytesRead += 1;
}
if (numBytesRead == numBytesToRead)
{
break;
}
}
Console.WriteLine("The filesize: " + numBytesRead); // this is what we need to do for the Firmware updater app to send to bootloader.
fsOut.Close(); // close file
Console.WriteLine(Path.GetFileName(inputFilename) + " has been decrypted successfully! New filename: " + Path.GetFileName(outputFilename));
}
