Cards.cs

public interface ICardsClient
{	
	Task<VirgilCardDTO> Create(
		string identityValue, 
		IdentityType identityType, 
		IDictionary<string, string> customData, 
		byte[] publicKey, 
		byte[] privateKey
	);
		
	Task<VirgilCardDTO> Create(
		string identityValue, 
		IdentityType identityType, 
		IDictionary<string, string> customData, 
		Guid publicKey, 
		byte[] privateKey
	);
		
	Task<VirgilSignDTO> Sign(
		Guid signedCardId,
		string signedCardHash,
		Guid signerCardId,
        	byte[] signerPrivateKey
        );
		
	Task Unsign(
		Guid signedCardId,
	        Guid signerCardId,
	        byte[] privateKey
	);
		
	Task<IList<VirgilCardDTO>> Search(
		string value,
		VirgilIdentityType? type, 
		List<Guid> relations,
	        bool? includeUnconfirmed,
	        Guid signerVirgilCardId,
	        byte[] privateKey
	);
}

IdentityType.cs

public enum IdentityType
{
	Email,
	Application
}

KeysClient.cs

public class KeysClient
{
	public KeysClient(string accessToken)
	{		
		throw new NotImplementedException();
	}
	
	public ICardsClient Cards { get; }
	public IPublicKeysClient PublicKeys { get; }	
}

PublicKeys.cs

public interface IPublicKeysClient
{
	Task<PublicKeyDto> Get(Guid publicKeyId);
	
	Task<GetPublicKeyExtendedResponse> GetExtended(
		Guid publicKeyId,
		Guid virgilCardId,
		byte[] privateKey
	);
} 

Usage.cs

var keysClient = new KeysClient("{ACCESS_TOKEN}");

keysClient.Cards.Create(...);
keysClient.Cards.Sign(...);
keysClient.Cards.Unsign(...);
keysClient.Cards.Search(...);

keysClient.PublicKeys.Get(...);