// Encrypt the data in the input stream into the output stream.
public static void CryptStream(string password, Stream in_stream, Stream out_stream, bool encrypt)
{
// Make an AES service provider.
AesCryptoServiceProvider aes_provider = new AesCryptoServiceProvider();
// Find a valid key size for this provider.
int key_size_bits = 0;
for (int i = 1024; i > 1; i--)
{
if (aes_provider.ValidKeySize(i))
{
key_size_bits = i;
break;
}
}
// Get the block size for this provider.
int block_size_bits = aes_provider.BlockSize;
// Generate the key and initialization vector.
byte[] key = null;
byte[] iv = null;
byte[] salt = { 0x0, 0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0xF1, 0xF0, 0xEE, 0x21, 0x22, 0x45 };
MakeKeyAndIV(password, salt, key_size_bits, block_size_bits, out key, out iv);
// Make the encryptor or decryptor.
ICryptoTransform crypto_transform;
if (encrypt)
{
crypto_transform = aes_provider.CreateEncryptor(key, iv);
}
else
{
crypto_transform = aes_provider.CreateDecryptor(key, iv);
}
// Attach a crypto stream to the output stream.
// Closing crypto_stream sometimes throws an
// exception if the decryption didn't work
// (e.g. if we use the wrong password).
try
{
using (CryptoStream crypto_stream = new CryptoStream(out_stream, crypto_transform, CryptoStreamMode.Write))
{
// Encrypt or decrypt the file.
const int block_size = 1024;
byte[] buffer = new byte[block_size];
int bytes_read;
while (true)
{
// Read some bytes.
bytes_read = in_stream.Read(buffer, 0, block_size);
if (bytes_read == 0) break;
// Write the bytes into the CryptoStream.
crypto_stream.Write(buffer, 0, bytes_read);
}
} // using crypto_stream
}
catch
{
}
crypto_transform.Dispose();
}
// Note that extension methods must be defined in a non-generic static class.
// Encrypt or decrypt the data in in_bytes[] and return the result.
public static byte[] CryptBytes(string password, byte[] in_bytes, bool encrypt)
{
// Make an AES service provider.
AesCryptoServiceProvider aes_provider = new AesCryptoServiceProvider();
// Find a valid key size for this provider.
int key_size_bits = 0;
for (int i = 1024; i > 1; i--)
{
if (aes_provider.ValidKeySize(i))
{
key_size_bits = i;
break;
}
}
Debug.Assert(key_size_bits > 0);
// Get the block size for this provider.
int block_size_bits = aes_provider.BlockSize;
// Generate the key and initialization vector.
byte[] key = null;
byte[] iv = null;
byte[] salt = { 0x0, 0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0xF1, 0xF0, 0xEE, 0x21, 0x22, 0x45 };
MakeKeyAndIV(password, salt, key_size_bits, block_size_bits, out key, out iv);
// Make the encryptor or decryptor.
ICryptoTransform crypto_transform;
if (encrypt)
{
crypto_transform = aes_provider.CreateEncryptor(key, iv);
}
else
{
crypto_transform = aes_provider.CreateDecryptor(key, iv);
}
// Create the output stream.
using (MemoryStream out_stream = new MemoryStream())
{
// Attach a crypto stream to the output stream.
using (CryptoStream crypto_stream = new CryptoStream(out_stream,
crypto_transform, CryptoStreamMode.Write))
{
// Write the bytes into the CryptoStream.
crypto_stream.Write(in_bytes, 0, in_bytes.Length);
try
{
crypto_stream.FlushFinalBlock();
}
catch (CryptographicException e)
{
throw e;
}
catch
{
// Re-throw this exception.
throw;
}
// return the result.
return out_stream.ToArray();
}
}
}
