Credential.cs

using System;

namespace Identity.Models
{
    public enum CredentialType
    {
        Password,
        PublicKey,
        Token,
    };

    public abstract class Credential
    {
        protected Credential(CredentialType credentialType)
        {
            CredentialType = credentialType;
        }

        public CredentialType CredentialType { get; set; }
        public DateTime CreationTime { get; set; }
    }

    public class PasswordCredential : Credential
    {
        public PasswordCredential(byte[] salt, byte[] key)
            : base(CredentialType.Password)
        {
            Salt = salt;
            Key = key;
        }

        public byte[] Salt { get; set; }
        public byte[] Key { get; set; }
    }

    public class PublicKeyCredential : Credential
    {
        public PublicKeyCredential(byte[] publicKey)
            : base(CredentialType.PublicKey)
        {
            PublicKey = publicKey;
        }

        public byte[] PublicKey { get; set; }
    }
}