ECDHPublicBcpgKey
using Org.BouncyCastle.Asn1;
using Org.BouncyCastle.Math;
using Org.BouncyCastle.Math.EC;
using System;
namespace Org.BouncyCastle.Bcpg
{
public class ECDHPublicBcpgKey : ECPublicBcpgKey
{
private byte reserved;
private HashAlgorithmTag hashFunctionId;
private SymmetricKeyAlgorithmTag symAlgorithmId;
public virtual byte Reserved => reserved;
public virtual HashAlgorithmTag HashAlgorithm => hashFunctionId;
public virtual SymmetricKeyAlgorithmTag SymmetricKeyAlgorithm => symAlgorithmId;
public unsafe ECDHPublicBcpgKey(BcpgInputStream bcpgIn)
: base(bcpgIn)
{
if (bcpgIn.RequireByte() != 3)
throw new InvalidOperationException("KDF parameters size of 3 expected.");
Span<byte> buffer = new Span<byte>(stackalloc byte[3], 3);
bcpgIn.ReadFully(buffer);
reserved = buffer[0];
hashFunctionId = (HashAlgorithmTag)buffer[1];
symAlgorithmId = (SymmetricKeyAlgorithmTag)buffer[2];
VerifyHashAlgorithm();
VerifySymmetricKeyAlgorithm();
}
public ECDHPublicBcpgKey(DerObjectIdentifier oid, ECPoint point, HashAlgorithmTag hashAlgorithm, SymmetricKeyAlgorithmTag symmetricKeyAlgorithm)
: base(oid, point)
{
reserved = 1;
hashFunctionId = hashAlgorithm;
symAlgorithmId = symmetricKeyAlgorithm;
VerifyHashAlgorithm();
VerifySymmetricKeyAlgorithm();
}
public ECDHPublicBcpgKey(DerObjectIdentifier oid, BigInteger point, HashAlgorithmTag hashAlgorithm, SymmetricKeyAlgorithmTag symmetricKeyAlgorithm)
: base(oid, point)
{
reserved = 1;
hashFunctionId = hashAlgorithm;
symAlgorithmId = symmetricKeyAlgorithm;
VerifyHashAlgorithm();
VerifySymmetricKeyAlgorithm();
}
public override void Encode(BcpgOutputStream bcpgOut)
{
base.Encode(bcpgOut);
bcpgOut.WriteByte(3);
bcpgOut.WriteByte(reserved);
bcpgOut.WriteByte((byte)hashFunctionId);
bcpgOut.WriteByte((byte)symAlgorithmId);
}
private void VerifyHashAlgorithm()
{
HashAlgorithmTag hashAlgorithmTag = hashFunctionId;
if ((uint)(hashAlgorithmTag - 8) > 2)
throw new InvalidOperationException("Hash algorithm must be SHA-256 or stronger.");
}
private void VerifySymmetricKeyAlgorithm()
{
SymmetricKeyAlgorithmTag symmetricKeyAlgorithmTag = symAlgorithmId;
if ((uint)(symmetricKeyAlgorithmTag - 7) > 2)
throw new InvalidOperationException("Symmetric key algorithm must be AES-128 or stronger.");
}
}
}