data annotation for passwords
[Required]
[StringLength(18, ErrorMessage = "The {0} must be at least {2} characters long.", MinimumLength = 6)]
[RegularExpression(@"^((?=.*[a-z])(?=.*[A-Z])(?=.*\d)).+$"]
[DataType(DataType.Password)]
[Display(Name = "Password")]
public string Password { get; set; }