public bool Decode(byte[] data, string password)
{
var msEncoded = new MemoryStream(data);
byte[] buffer = new byte[4];
msEncoded.Read(buffer, 0, 4);
int encodedBytes = BitConverter.ToInt32(buffer, 0);
buffer = new byte[encodedBytes];
msEncoded.Read(buffer, 0, buffer.Length);
byte[] decodedBytes = EncryptionManager.DecryptData(buffer, password);
msEncoded.Read(buffer, 0, 4);
int hashByteLength = BitConverter.ToInt32(buffer, 0);
if (hashByteLength > 512)
{
return(false);
}
byte[] hashBytesFromData = new byte[hashByteLength];
msEncoded.Read(hashBytesFromData, 0, hashBytesFromData.Length);
byte[] hashBytesFromDecodedDataBytes = SHA512.Create().ComputeHash(decodedBytes, 0, decodedBytes.Length);
bool hashCompareResult = GeneralConverters.ByteArrayToBase64(hashBytesFromData) == GeneralConverters.ByteArrayToBase64(hashBytesFromDecodedDataBytes);
if (!hashCompareResult)
{
return(false);
}
var msDecoded = new MemoryStream(decodedBytes);
buffer = new byte[4];
msDecoded.Read(buffer, 0, buffer.Length);
int leftPaddingLength = BitConverter.ToInt32(buffer, 0);
msDecoded.Read(buffer, 0, buffer.Length);
int rightPaddingLength = BitConverter.ToInt32(buffer, 0);
msDecoded.Read(buffer, 0, buffer.Length);
int totalLength = BitConverter.ToInt32(buffer, 0);
byte[] decodedDataBlock = new byte[totalLength];
msDecoded.Read(decodedDataBlock, 0, decodedDataBlock.Length);
byte[] sharedSecretBytes = new byte[totalLength - leftPaddingLength - rightPaddingLength];
Buffer.BlockCopy(decodedDataBlock, leftPaddingLength, sharedSecretBytes, 0, sharedSecretBytes.Length);
SharedSecret = GeneralConverters.GetStringFromByteArray(sharedSecretBytes);
return(true);
}
public byte[] Encode(string password)
{
var secureRandom = new SecureRandomGenerator();
var msBlock = new MemoryStream();
var msContent = new MemoryStream();
int leftPaddingLength = secureRandom.GetRandomInt(64, 512);
int rightPaddingLength = secureRandom.GetRandomInt(64, 512);
byte[] sharedSecretBytes = GeneralConverters.GetByteArrayFromString(SharedSecret);
byte[] buffer = BitConverter.GetBytes(leftPaddingLength);
msBlock.Write(buffer, 0, buffer.Length);
buffer = BitConverter.GetBytes(rightPaddingLength);
msBlock.Write(buffer, 0, buffer.Length);
buffer = BitConverter.GetBytes(leftPaddingLength + rightPaddingLength + sharedSecretBytes.Length);
msBlock.Write(buffer, 0, buffer.Length);
msBlock.Write(secureRandom.GetRandomData(leftPaddingLength), 0, leftPaddingLength);
msBlock.Write(sharedSecretBytes, 0, sharedSecretBytes.Length);
msBlock.Write(secureRandom.GetRandomData(rightPaddingLength), 0, rightPaddingLength);
byte[] encodeBytes = msBlock.ToArray();
encodeBytes = EncryptionManager.EncryptData(encodeBytes, password);
byte[] hashBytes = SHA512.Create().ComputeHash(encodeBytes, 0, encodeBytes.Length);
buffer = BitConverter.GetBytes(encodeBytes.Length);
msContent.Write(buffer, 0, buffer.Length);
msBlock.WriteTo(msContent);
buffer = BitConverter.GetBytes(hashBytes.Length);
msContent.Write(buffer, 0, buffer.Length);
msContent.Write(hashBytes, 0, hashBytes.Length);
return(msContent.ToArray());
}