What means and methods are used to verify user personal data?

Checking user personal data in C# typically involves validation and authentication.

Validation — verifying the correctness of entered data (e.g., email format, password length). This often uses attributes from the System.ComponentModel.DataAnnotations namespace:

public class User
{
    [Required]
    [EmailAddress]
    public string Email { get; set; }

    [Required]
    [StringLength(100, MinimumLength = 6)]
    public string Password { get; set; }
}

Validation can be performed using Validator.TryValidateObject.

Authentication — verifying the user's identity, for example, by comparing the entered password with a hash stored in the database. Secure password storage uses hashing with salt (e.g., Rfc2898DeriveBytes).

You can also use third-party libraries and services (e.g., ASP.NET Identity) that provide ready-made mechanisms for user verification and management.

Thus, the process of checking personal data includes:

• Format validation and required fields
• Authenticity verification (authentication)
• If necessary, verification via email or SMS

Example of object validation:

var user = new User { Email = "test@example.com", Password = "123456" };
var context = new ValidationContext(user);
var results = new List<ValidationResult>();
bool isValid = Validator.TryValidateObject(user, context, results, true);