private void DecodeContent(byte[] encoded)
{
var parser = new Asn1Parser(encoded);
parser.ReadObject <DerSequenceParser>();
var version = parser.ReadObject <DerInteger>().Value.IntValue;
if (1 != version)
{
throw new ParsingException($"Expected version 1, got {version}");
}
var octetString = (DerOctetString)parser.ReadObject <DerOctetStringParser>().ToAsn1Object();
privateKey = new BigInteger(1, octetString.GetOctets());
parser.ReadObject <BerTaggedObjectParser>();
var oid = parser.ReadObject <DerObjectIdentifier>();
if (!BrainpoolP320R1.ObjectIdentifier.Equals(oid))
{
throw new ParsingException($"Expected BrainpoolP320r1 ({BrainpoolP320R1.ObjectIdentifier}), got {oid}");
}
var obj = parser.ReadObject();
if (obj == null)
{
return;
}
Asn1Parser.CheckObject <BerTaggedObjectParser>(obj);
try
{
publicKey = BrainpoolP320R1.Curve.DecodePoint(parser.ReadObject <DerBitString>().GetBytes()).Normalize();
}
catch (ArgumentException e)
{
throw new ParsingException("Could not decode point on curve", e);
}
BrainpoolP320R1.G.Multiply(privateKey).Normalize();
if (!BrainpoolP320R1.G.Multiply(privateKey).Equals(publicKey))
{
throw new ParsingException("Public key does not belong to private key");
}
}
private void DecodePayload(Asn1Parser payloadParser, bool isPseudonym)
{
schemeVersion = payloadParser.ReadObject <DerInteger>().Value.IntValue;
schemeKeyVersion = payloadParser.ReadObject <DerInteger>().Value.IntValue;
payloadParser.ReadObject <DerIA5String>(); //Creator, not used
recipient = payloadParser.ReadObject <DerIA5String>().GetString();
recipientKeySetVersion = payloadParser.ReadObject <DerInteger>().Value.IntValue;
if (isPseudonym)
{
var obj = payloadParser.ReadObject();
if (obj is DerIA5String derIa5String)
{
derIa5String.GetString();
payloadParser.ReadObject <DerInteger>(); //Type, not used
}
else
{
Asn1Parser.CheckObject <DerInteger>(obj); //Type, not used
}
}
payloadParser.ReadObject <DerSequenceParser>();
points = new ECPoint[3];
for (var i = 0; i < points.Length; i++)
{
var octet =
(DerOctetString)payloadParser.ReadObject <DerOctetStringParser>().ToAsn1Object();
try
{
points[i] = BrainpoolP320R1.Curve.DecodePoint(octet.GetOctets());
}
catch (ArgumentException e)
{
throw new ParsingException("Could not decode point on curve", e);
}
}
}