Make the encryption explicit in the domain model

EncryptedColumnInEntity.cs

 public class EncryptedColumnInEntity : Entity
    {
        protected virtual byte[] EncryptedText { get; set; }

        /// <summary>
        /// Decryptes the text stored in the database
        /// </summary>
        /// <exception cref="CryptographicException">Throws CryptographicException when the password isn't valid</exception>
        /// <param name="password">The password which the text was encrypted with</param>
        /// <returns>Decrypted text</returns>
        public virtual string GetText(string password)
        {
            var salt = EncryptedText.Take(16).ToArray();
            using (var aes = new AesManaged())
            using (var byteDeriver = new Rfc2898DeriveBytes(password, salt))
            using (var decryptor = aes.CreateDecryptor(byteDeriver.GetBytes(32), byteDeriver.GetBytes(16)))
            {
                var decryptedBytes = decryptor.TransformFinalBlock(EncryptedText, 16, EncryptedText.Length - 16);
                return Encoding.UTF8.GetString(decryptedBytes);        
            }
        }

        public virtual void SetText(string password, string inputText)
        {
            using (var aes = new AesManaged())
            using (var byteDeriver = new Rfc2898DeriveBytes(password, 16))
            using (var encryptor = aes.CreateEncryptor(byteDeriver.GetBytes(32), byteDeriver.GetBytes(16)))
            {
                var textBytes = Encoding.UTF8.GetBytes(inputText);
                var encryptedBytes = encryptor.TransformFinalBlock(textBytes, 0, textBytes.Length);
                EncryptedText = byteDeriver.Salt.Concat(encryptedBytes).ToArray();
            }
        }

        public virtual void ChangePassword(string oldpassword, string newpassword)
        {
            SetText(newpassword, GetText(oldpassword));
        }
    }