/// <summary>
/// Serializes a SealedBiscuit to a byte array
/// </summary>
/// <returns></returns>
public Either <FormatError, byte[]> Serialize()
{
Format.Schema.SealedBiscuit biscuit = new Format.Schema.SealedBiscuit()
{
Signature = ByteString.CopyFrom(signature),
Authority = ByteString.CopyFrom(Authority)
};
foreach (var block in Blocks)
{
biscuit.Blocks.Add(ByteString.CopyFrom(block));
}
try
{
using MemoryStream stream = new MemoryStream();
biscuit.WriteTo(stream);
byte[] data = stream.ToArray();
return(data);
}
catch (IOException e)
{
return(new SerializationError(e.ToString()));
}
}
/// <summary>
/// Deserializes a SealedBiscuit from a byte array
/// </summary>
/// <param name="slice"></param>
/// <param name="secret"></param>
/// <returns></returns>
static public Either <Error, SealedBiscuit> FromBytes(byte[] slice, byte[] secret)
{
try
{
Format.Schema.SealedBiscuit data = Format.Schema.SealedBiscuit.Parser.ParseFrom(slice);
using HMACSHA256 hmac = new HMACSHA256(secret);
byte[] authority = data.Authority.ToByteArray();
List <byte> toHash = new List <byte>(authority);
List <byte[]> blocks = new List <byte[]>();
foreach (ByteString block in data.Blocks)
{
byte[] byteBlock = block.ToByteArray();
blocks.Add(byteBlock);
toHash.AddRange(byteBlock);
}
byte[] calculated = hmac.ComputeHash(toHash.ToArray());
byte[] signature = data.Signature.ToByteArray();
if (calculated.Length != signature.Length)
{
return(new InvalidFormat());
}
int result = 0;
for (int i = 0; i < calculated.Length; i++)
{
result |= calculated[i] ^ signature[i];
}
if (result != 0)
{
return(new SealedSignature());
}
return(new SealedBiscuit(authority, blocks, signature));
}
catch (Exception e)
{
return(new DeserializationError(e.ToString()));
}
}
