password must be 6 characters i mvc

[Required]
[MembershipPassword(
    MinRequiredNonAlphanumericCharacters = 1,
    MinNonAlphanumericCharactersError = "Your password needs to contain at least one symbol (!, @, #, etc).",
    ErrorMessage = "Your password must be 6 characters long and contain at least one symbol (!, @, #, etc).",
    MinRequiredPasswordLength = 6
)]
[DataType(DataType.Password)]
[Display(Name = "New password")]
public string NewPassword { get; set; }