public MegaAesCtrStreamCrypter(Stream stream)
: base(stream, stream.Length, Mode.Crypt, Crypto.CreateAesKey(), Crypto.CreateAesKey().CopySubArray(8))
{
}
// Token: 0x060008D4 RID: 2260 RVA: 0x0004B04C File Offset: 0x0004924C
public static byte[] EncryptAttributes(Attributes attributes, byte[] nodeKey)
{
byte[] array = ("MEGA" + JsonConvert.SerializeObject(attributes, Formatting.None)).ToBytes();
array = array.CopySubArray(array.Length + 16 - array.Length % 16, 0);
return(Crypto.EncryptAes(array, nodeKey));
}
public override int Read(byte[] buffer, int offset, int count)
{
if (this.position == this.streamLength)
{
return(0);
}
for (long pos = this.position; pos < Math.Min(this.position + count, this.streamLength); pos += 16)
{
// We are on a chunk bondary
if (this.chunksPositions.Any(chunk => chunk == pos))
{
if (pos != 0)
{
// Compute the current chunk mac data on each chunk bondary
this.ComputeChunk();
}
// Init chunk mac with Iv values
for (int i = 0; i < 8; i++)
{
this.currentChunkMac[i] = this.iv[i];
this.currentChunkMac[i + 8] = this.iv[i];
}
}
this.IncrementCounter();
// Iterate each AES 16 bytes block
byte[] input = new byte[16];
byte[] output = new byte[input.Length];
int inputLength = this.stream.Read(input, 0, input.Length);
if (inputLength != input.Length)
{
// Sometimes, the stream is not finished but the read is not complete
inputLength += this.stream.Read(input, inputLength, input.Length - inputLength);
}
// Merge Iv and counter
byte[] ivCounter = new byte[16];
Array.Copy(this.iv, ivCounter, 8);
Array.Copy(this.counter, 0, ivCounter, 8, 8);
byte[] encryptedIvCounter = Crypto.EncryptAes(ivCounter, this.fileKey);
for (int inputPos = 0; inputPos < inputLength; inputPos++)
{
output[inputPos] = (byte)(encryptedIvCounter[inputPos] ^ input[inputPos]);
this.currentChunkMac[inputPos] ^= (this.mode == Mode.Crypt) ? input[inputPos] : output[inputPos];
}
// Copy to buffer
Array.Copy(output, 0, buffer, offset + pos - this.position, Math.Min(output.Length, this.streamLength - pos));
// Crypt to current chunk mac
this.currentChunkMac = Crypto.EncryptAes(this.currentChunkMac, this.fileKey);
}
long len = Math.Min(count, this.streamLength - this.position);
this.position += len;
// When stream is fully processed, we compute the last chunk
if (this.position == this.streamLength)
{
this.ComputeChunk();
// Compute Meta MAC
for (int i = 0; i < 4; i++)
{
this.metaMac[i] = (byte)(this.fileMac[i] ^ this.fileMac[i + 4]);
this.metaMac[i + 4] = (byte)(this.fileMac[i + 8] ^ this.fileMac[i + 12]);
}
this.OnStreamRead();
}
return((int)len);
}
