Question

COSC 359

User Authentication

Description

A widely used password security technique is the use of hashed passwords and a salt value. This scheme is found on virtually all UNIX variants as well as on a number of other operating systems as shown in Figure 3.1 bellow.

To load a new password into the system, the user selects or is assigned a password. This password is combined with a fixed-length salt value. In older implementations, this value is related to the time at which the password is assigned to the user. Newer implementations use a pseudorandom or random number. The password and salt serve as inputs to a hashing algorithm to produce a fixed-length hash code. The hash algorithm is designed to be slow to execute to thwart attacks. The hashed password is then stored, together with a plaintext copy of the salt, in the password file for the corresponding user ID. The hashed-password method has been shown to be secure against a variety of cryptanalytic attacks [WAGN00].

When a user attempts to log on to a UNIX system, the user provides an ID and a password. The operating system uses the ID to index into the password file and retrieve the plaintext salt and the encrypted password. The salt and user-supplied passwords are used as input to the encryption routine. If the result matches the stored value, the password is accepted.

// PART A: ID/PASSWORD CREATION

Write the necessary C++ code (or a language of your choice) for the following activities:

Create user ID and Password pair by asking users to input ID/Password. Check the input and help users to choose an acceptable ID/Password based on the company security policy.

Create a Salt value, add it to the Password and use a hash function to encrypt both Salt and Password.

Store user ID, Salt and hashed password in ID-PASSWORD.TXT

// PART B: USER AUTHENTICATION

Enhance your code from PART A for the following activities:

Ask users for ID/Password pair

Authenticate users using ID.txt and the ID-PASSWORD.TXT files.

Password Password File User ID Salt Hash code Salt slow hash function Load (a) Loading a new password Password File User id User ID Sa Hash code Salt Select Password slow hash function Hashed password Compare (b) Verifying a password Figure 3.1 UNIX Password Scheme

Answer 1

#include <iostream>

#include <fstream>

#include<string>

using namespace std;

class PasswordGeneration

{

private:

string userid;

string password;

int seed;

unsigned long hashValue;

public:

PasswordGeneration();

void setPassword();

unsigned int hash(string password);

void authenticateUser();

};

PasswordGeneration :: PasswordGeneration()

{

seed=2;

}

//Question 1

void PasswordGeneration ::setUserID()

{

cout<<"Enter UserID : ";

//getline(cin,userid);

cin >> userid;

}

void PasswordGeneration :: setPassword()

{

string error;

cout << "Enter Password : ";

cin >> password;

//getline(cin,password);

if(password.empty())

error = "Password shouldn't be empty";

else if(password.length() < 9)

error = "Password length must greater than 8";

else if(password.find_first_of("@#!*&_") ==string::npos)

error = "Password must contain any special character of these @,#,!,*,& and _";

else if(password.find_first_of("1234567890") == string::npos)

error = "Password must contain at least one digit";

else

{

error="Password is Accepted";

storeDatabase();

}

cout <<error << endl;

}

//Question 2

unsigned int PasswordGeneration ::hash(string password)

{

unsigned long hash = seed;

const char "pword=password.c_str();

while (*pword)

{

hash = hash * 101 + *pword++;

}

hashValue = hash;

}

//Question 3

void PasswordGeneration :: storeDatabase()

{

fstream uidfile("ID.txt",ios::app);

uidfile << userid;

uidfile.close();

fstream passwordfile("ID-PASSWORD.txt");

passwordfile << hash(password) ;

passwordfile.close();

}

//Part B: UserAuthentication

void PasswordGeneration :: authenticateUser()

{

string uid,pw;

cout << "User ID:";

cin >> uid;

cout << "User Password :";

cin >> pw;

unsigned long passhash=hash(pw);

string txtstr;

bool ustatus=false;

//reading id from the ID.txt file

ifstreamfile ("ID.txt");

while(getline(file,txtstr))

{

if(uid == txtstr)

ustatus =true;

}

file.close();

if(!ustatus)

{

cout <<"Invalid UserID"<<endl;

return;

}

txtstr="";

ustatus=false;

//reading password from the ID-PASSWORD.txt file

ifstream file2("ID-PASSWORD.txt");

while(getline(file2,txtstr))

{

if(passhash == hash(txtstr))

ustatus =true;

}

file2close();

if(!ustatus)

{

cout<<"Invalid Password"<<endl;

return;

}

}

cout<<"User Login Successfully...!"<<endl;

}

int main()

{

//PasswordGeneration obj("suresh","sure4has!urr");

PasswordGeneration obj;

// //Creation of User -> Part - A

obj.setUserID();

obj.setPassword();

//Authentication of User -> Part - B

obj.authenticateUser();

return 0;

}