Password Validation in C++

Password Validation is an essential aspect of Cybersecurity that is often overlooked. Passwords are the entry line of defense against unknown access to an account or system, and ensuring their strength can prevent a multitude of cyber attacks. In this article, we will explore Password Validation in C++ and look at various techniques and methods to implement Password Validation in C++.

What is Password Validation?

Password Validation is the process of checking the strength and security of a password entered by a user. The validation process involves verifying if the password meets certain criteria, such as length, complexity, and uniqueness. Password Validation is crucial in preventing unauthorized access to accounts and systems.

Password Validation Techniques:

There are various Password Validation techniques that can be used to ensure the strength and security of a password. Some of the commonly used techniques include:

Length Checking:

This technique involves checking the length of the password. Passwords with a minimum length requirement are considered more secure than shorter ones.

Complexity Checking:

This technique involves checking the complexity of the password. Passwords that contain a combination of uppercase and lowercase letters, numbers, and special characters are considered more complex and secure.

Dictionary Checking:

This technique involves checking if the password is a dictionary word or a commonly used password. Such passwords are easily guessed and can compromise the security of the account or system.

History Checking:

This technique involves checking if the password has been used before. Passwords that have been used before are easily guessed and, therefore, not secure.

Password Validation in C++:

Password Validation in C++ involves implementing one or more of the password validation techniques mentioned above. Here are some of the ways to implement password validation in C++.

Length Checking in C++:

Length checking in C++ can be implemented using the string length() function. This function returns the length of a given string. Below is an example of how to implement length checking in C++:

C++ code:

#include <iostream>
#include <string>
using namespace std;

int main() {
    string password;
    cout << "Enter password: ";
    getline(cin, password);
    if (password.length() < 8) {
        cout << "Password is too short." << endl;
    }
    else {
        cout << "Password is strong." << endl;
    }
    return 0;
}

Output:

Enter password: abdh
Password is too short.

In this example, the user is prompted to enter a password, and the length() function is used to check if the password has a minimum length of 8 characters.

Complexity Checking in C++:

Complexity Checking in C++ can be implemented using the isdigit(), islower(), isupper(), and ispunct() functions. These functions check if a character is a digit, lowercase letter, uppercase letter, or punctuation character, respectively. Below is an example of implementing complexity checking in C++:

C++ Code:

#include <iostream>
#include <string>
using namespace std;

int main() {
    string password;
    bool has_upper = false, has_lower = false, has_digit = false, has_punct = false;
    cout << "Enter password: ";
    getline(cin, password);
    for (char c : password) {
        if (isupper(c)) {
            has_upper = true;
        }
        if (islower(c)) {
            has_lower = true;
        }
        if (isdigit(c)) {
            has_digit = true;
        }
        if (ispunct(c)) {
            has_punct = true;
        }
    }
    if (has_upper && has_lower && has_digit && has_punct && password.length() >= 8) {
        cout << "Password is strong." << endl;
    }
    else {
        cout << "Password is weak." << endl;
    }
    return 0;
}

Output:

Enter password: gdhd
Password is weak.

Explanation:

In the above C++ Code we validate the password with various parameters. A password is considered to be a strong password if it consists of capital letters, small letters, digits, and some special characters like punctuation, etc. We have taken a user input password, and we are checking what parameters are true and what are false. If any parameter is false, we will print that password is weak; otherwise, it is strong.

We can use Regular Expressions for password validation.

C++ Code:

#include <regex>
#include <iostream>
using namespace std;
 
bool validatePassword(string password)
{
    // regex pattern for password validation
    regex pattern("(?=.*[a-z])(?=.*[A-Z])(?=.*[0-9])(?=.*[@#$%^&+=])(?=\\S+$).{8,}");
 
    // check if the password matches the pattern
    if (regex_match(password, pattern))
    {
        return true;
    }
    else
    {
        return false;
    }
}
 
int main()
{
    string password;
    cout << "Enter password: ";
    getline(cin, password);
 
    if (validatePassword(password))
    {
        cout << "Password is valid." << endl;
    }
    else
    {
        cout << "Password is invalid." << endl;
    }
 
    return 0;
}

Explanation:

In the above code, we have a function validatePassword that takes a string as input and returns a boolean value indicating whether the password is valid or not. We use a Regular Expression pattern to check if the password meets certain requirements:

(?=.*[a-z]): The password must have at least one lowercase letter.

(?=.*[A-Z]): The password must contain at least one uppercase letter.

(?=.*[0-9]): The password must contain at least one number.

(?=.*[@#$%^&+=]): The password must contain at least one special character.

(?=\\S+$): The password must not contain any whitespace.

.{8,}: The password must be at least 8 characters long.

If the password matches the pattern, the function returns true. Otherwise, it returns false.

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