1st question in the following code //all method return types are for declaration purposes //feel free to change them to necessary return types import java.util.Arrays; import java.util.Base64; import java.util.HashMap; import java.util.Map; import java.util.Random; import java.util.Scanner; import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; import java.sql.PreparedStatement; import java.sql.Statement; import java.sql.ResultSet; import javax.crypto.*; import javax.crypto.spec.*; class PasswordManager { private static final String SECRET_KEY = null; private static final String ALGORITHM = "AES"; private static final String ENCODING = "UTF-8"; // Current key with invalid length private static final String FIXED_KEY = "Infotrixs@Key123"; private Cipher cipher; private SecretKeySpec secretKey; private static Map<String, String> users = new HashMap<>(); static Scanner scanner = new Scanner(System.in); public PasswordManager() throws Exception { cipher = Cipher.getInstance(ALGORITHM); byte[] key = FIXED_KEY.getBytes(ENCODING); key = Arrays.copyOf(key, 16); //Pad key to the required 128-bit (16-byte) length secretKey = new SecretKeySpec(key, ALGORITHM); } private String encrypt(String password) throws Exception { cipher.init(Cipher.ENCRYPT_MODE, secretKey); byte[] encryptedBytes = cipher.doFinal(password.getBytes(ENCODING)); return Base64.getEncoder().encodeToString(encryptedBytes); } private String decrypt(String encryptedPassword) throws Exception { cipher.init(Cipher.DECRYPT_MODE, secretKey); byte[] encryptedBytes = Base64.getDecoder().decode(encryptedPassword); byte[] decryptedBytes = cipher.doFinal(encryptedBytes); return new String(decryptedBytes, ENCODING); } public void registerUser() { System.out.println("Welcome to User Registration!"); System.out.println("Enter a username:"); String username = scanner.next(); String masterPassword=null; System.out.print("Do you wish to for us to generate a strong password? (Y/N)"); String recc=scanner.next(); if(recc.equalsIgnoreCase("Y")) { System.out.println("personalize your Password:"); System.out.println("Specify the length of the password between(8-16): "); int passlen=scanner.nextInt(); System.out.println("include Uppercase? (Y/N)"); boolean UpperCase=(scanner.next().equalsIgnoreCase("Y")?true:false); System.out.println("include lowercase? (Y/N)"); boolean lowerCase=(scanner.next().equalsIgnoreCase("Y")?true:false); System.out.println("include digits? (Y/N)"); boolean digits=(scanner.next().equalsIgnoreCase("Y")?true:false); System.out.println("include special Characters? (Y/N)"); boolean spChar=(scanner.next().equalsIgnoreCase("Y")?true:false); masterPassword= generatePassword(passlen, UpperCase, lowerCase, digits, spChar); System.out.println("This is your master password : "+masterPassword); } else { boolean strength=false; while(strength==false) { System.out.println("Enter a master password:"); masterPassword = scanner.next(); strength=isPasswordStrongEnough(masterPassword); if(isPasswordStrongEnough(masterPassword)==false) { System.out.println("Password must contain atleast one Uppercase,Lower Case,\n" + "a number and a special charachter and must be of 8-16 characters length."); } } } String encryptedPassword=null; try{ encryptedPassword= encrypt(masterPassword); }catch(Exception e) { System.out.println(e.getMessage()); } insertUserIntoUserTable(username,encryptedPassword); loginUser(); } public void loginUser() { System.out.println("\t\t\tWelcome To Login page"); //contains code for Login of the user System.out.print("Enter Username: "); String username=scanner.next(); System.out.print("Enter Master Password:"); String password=scanner.next(); try{ if(password.equals(decrypt(checkPasswordFromDatabase(username)))) { System.out.println("user Login successfull\n\n"); Welcome(username); } else { System.out.println("username or password Incorrect, Please try again:"); loginUser(); } } catch(Exception e) { System.out.println("Username or password incorrect.\n"); System.out.println("Do you want to continue with login? (Y/N)"); String recc=scanner.next(); if(recc.equalsIgnoreCase("Y")) { loginUser(); } else { System.out.println("Thanks for using our application"); } } } public void exit() { System.out.println("Thanks for using this application!!"); } private Connection connectToDatabse() { //creation of database //SQL operations performed here String url="jdbc:sqlite:Database.db"; Connection connection=null; try{ connection=DriverManager.getConnection(url); } catch(SQLException e){ System.out.println(e.getMessage()); } return connection; } public void createUsersTableIfNotExist() { String createTable="CREATE TABLE IF NOT EXISTS profiles(\n" +"userid varchar PRIMARY KEY,\n" +"gmail_username varchar," +"password varchar," +"fb_username varchar," +"fb_password varchar," +"insta_username varchar," +"insta_password varchar" +");"; String createUserTable="CREATE TABLE IF NOT EXISTS users(\n" +"userid varchar PRIMARY KEY,\n" +"password varchar NOT NULL)"; //String dropTable="DROP TABLE users"; Connection conn=null; try{ conn=this.connectToDatabse(); Statement stmt=conn.createStatement(); stmt.execute(createUserTable); stmt.execute(createTable); } catch(SQLException e) { System.out.println(e.getMessage()); } finally { try { if (conn != null) { conn.close(); } } catch (SQLException ex) { System.out.println(ex.getMessage()); } } } public void insertUserIntoUserTable(String userid,String password) { String insertUser="INSERT INTO users (userid,password) Values(?,?)"; Connection conn=null; try { conn=this.connectToDatabse(); PreparedStatement pstmt=conn.prepareStatement(insertUser); pstmt.setString(1, userid); pstmt.setString(2, password); pstmt.executeUpdate(); System.out.println("User registered successfully!"); } catch (SQLException e) { System.out.println("user already exist"); }finally { try { if (conn != null) { conn.close(); } } catch (SQLException ex) { System.out.println(ex.getMessage()); } } } public String checkPasswordFromDatabase(String username) { String sql = "SELECT password FROM users WHERE userid='"+username+"';"; Connection conn=null; try { conn=this.connectToDatabse(); Statement stmt = conn.createStatement(); ResultSet rs = stmt.executeQuery(sql); if (rs.next()) { String value = rs.getString("password"); return value; } } catch (Exception e) { System.out.println("Line 190 "+e.getMessage()); } finally { try { if (conn != null) { conn.close(); } } catch (SQLException ex) { System.out.println(ex.getMessage()); } } return null; } public void Welcome(String username) { //CLI interface Welcome Screen //contains register,login,exit options boolean cont=true; System.out.println("\n\nHello "+username+"\n"); System.out.println("which action do you wish to perform?"); while(cont==true) { System.out.println("\n Chose one of these options"); System.out.println("1.Store Password\n2.Retrieve Password\n3.Log out"); int ua=scanner.nextInt(); switch (ua) { case 1: storePassword(username); break; case 2: retrievePassword(username); break; case 3: System.out.println("Log out and Exit? (Y/N)"); String logout=scanner.next(); if(logout.equalsIgnoreCase("Y")) { exit(); cont=false; } else { loginUser(); } break; } } } public void storePassword(String username) { System.out.println("\n We have few pre-defined profiles you can store of ,They are:"); System.out.println("1.Gmail\n2.Facebook\n3.Instagram\n4.Other"); int acc=scanner.nextInt(); switch (acc) { case 1: userChoiceForStoringPassword(username,"gmail_username","password"); break; case 2: userChoiceForStoringPassword(username, "fb_username","fb_password"); break; case 3: userChoiceForStoringPassword(username, "insta_username", "insta_password"); break; case 4: newColumnsDetails(username); break; } } public void newColumnsDetails(String username) { System.out.println("Enter custom account name"); String accName=scanner.next(); String passAccName=accName+"_password"; addColumnForOtherAccounts(accName, passAccName); userChoiceForStoringPassword(username, accName, passAccName); } public void userChoiceForStoringPassword(String username,String columnname, String passColumnName) { System.out.print("Enter Username: "); String uname=scanner.next(); System.out.print("\nEnter password: "); String Password=scanner.next(); String encryptedPass=null; try { encryptedPass=encrypt(Password); } catch (Exception e) { System.out.println("LIne 262"+ e.getMessage()); } insertPasswordsIntoUserTable(username,uname,columnname,passColumnName,encryptedPass); } public void insertPasswordsIntoUserTable(String userid,String uname,String columnName,String passColumnName,String password) { String insertUser="INSERT INTO profiles (userid,"+columnName+","+passColumnName+") Values(?,?,?)"; Connection conn=null; try { conn=this.connectToDatabse(); PreparedStatement pstmt=conn.prepareStatement(insertUser); pstmt.setString(1,userid); pstmt.setString(2, uname); pstmt.setString(3, password); pstmt.executeUpdate(); System.out.println("password has been stored successfully!"); } catch (SQLException e) { //System.out.println("line 284"+ e.getMessage()); addPasswordsIfUserExistInProfiles(userid, uname, columnName, passColumnName, password); }finally { try { if (conn != null) { conn.close(); } } catch (SQLException ex) { System.out.println(ex.getMessage()); } } } public void addPasswordsIfUserExistInProfiles(String userid,String uname,String columnName,String passColumnName,String password) { String sql="UPDATE profiles SET "+ columnName+"='"+uname+"',"+passColumnName+"='"+password+"' WHERE userid='"+userid+"'"; Connection conn=null; try { conn=this.connectToDatabse(); Statement stmt=conn.createStatement(); stmt.executeUpdate(sql); System.out.println("Password has been Stored successfully!!"); } catch (Exception e) { System.out.println("Line 342"+ e.getMessage()); }finally { try { if (conn != null) { conn.close(); } } catch (SQLException ex) { System.out.println(ex.getMessage()); } } } public void addColumnForOtherAccounts(String columnName,String passColumnName) { String sql="ALTER TABLE profiles ADD COLUMN "+columnName+" varchar"; String sql2="ALTER TABLE profiles ADD COLUMN "+passColumnName+" varchar"; Connection conn=null; try { conn=this.connectToDatabse(); Statement stmt=conn.createStatement(); stmt.execute(sql); stmt.execute(sql2); } catch (Exception e) { // TODO: handle exception System.out.println(""); }finally { try { if (conn != null) { conn.close(); } } catch (SQLException ex) { System.out.println(ex.getMessage()); } } } private static boolean isPasswordStrongEnough(String password) { // Check if the password contains at least one uppercase letter, one lowercase letter, one digit, and one special character boolean hasUppercase = false; boolean hasLowercase = false; boolean hasDigit = false; boolean hasSpecialCharacter = false; for (char ch : password.toCharArray()) { if (Character.isUpperCase(ch)) { hasUppercase = true; } else if (Character.isLowerCase(ch)) { hasLowercase = true; } else if (Character.isDigit(ch)) { hasDigit = true; } else { hasSpecialCharacter = true; } } return hasUppercase && hasLowercase && hasDigit && hasSpecialCharacter; } public void retrievePassword(String username) { System.out.println("Which Password you want to retrieve: "); System.out.println("1.Gmail \n2.facebook\n3.Instagram\n4.Other"); int ret=scanner.nextInt(); switch (ret) { case 1: userChoiceForRetrieving(username, "gmail_username", "password"); break; case 2: userChoiceForRetrieving(username, "fb_username", "fb_password"); break; case 3: userChoiceForRetrieving(username, "insta_username", "insta_password"); break; case 4: userChoiceForRetrievingOthers(username); break; } //retrieving the data(passwords and labels) from database using getDatabase //must come from decrypt() } public void userChoiceForRetrievingOthers(String username) { System.out.println("Profile name:"); String otherProfName=scanner.next(); String otherProfPass=otherProfName+"_password"; userChoiceForRetrieving(username, otherProfName, otherProfPass); } public void userChoiceForRetrieving(String username,String columnName,String passColumnName) { String profile_username=userChoiceForRetrievingUsername(username, columnName); String profile_password=null; try { profile_password=decrypt(userChoiceForRetrievingPassword(username, passColumnName)); } catch (Exception e) { System.out.println(e.getMessage()); } System.out.println("username: "+profile_username+"\nPassword: "+profile_password); } public String userChoiceForRetrievingUsername(String username,String columnName) { String sql="SELECT "+columnName+" From profiles WHERE userid='"+username+"'"; Connection conn=null; try { conn=this.connectToDatabse(); Statement stmt=conn.createStatement(); ResultSet res=stmt.executeQuery(sql); if (res.next()) { String value = res.getString(columnName); return value; } } catch (Exception e) { System.out.println("line 496"+e.getMessage()); } return null; } public String userChoiceForRetrievingPassword(String username,String passColumnName) { String sql="SELECT "+passColumnName+" From profiles WHERE userid='"+username+"'"; Connection conn=null; try { conn=this.connectToDatabse(); Statement stmt=conn.createStatement(); ResultSet res=stmt.executeQuery(sql); if (res.next()) { String value = res.getString(passColumnName); return value; } } catch (Exception e) { System.out.println("line 489"+e.getMessage()); } return null; } public void updatePassword() { //modifying the database by changing passwords //old passwords are not allowed } public void createAccount() { //update the database with account details. } public void userInterface() { //switch case for accessing all the important methods } public void menuInterface() { System.out.println("\t\t\t Welcome to Password Manager"); System.out.println("1.Register User"); System.out.println("2.Login User"); System.out.println("3.Exit"); int UI=scanner.nextInt(); switch (UI) { case 1: registerUser(); break; case 2: loginUser(); break; case 3: exit(); break; } } public static void main(String[] args) throws Exception { //java -classpath ".;sqlite-jdbc-3.42.0.0.jar" PasswordManager PasswordManager pm=new PasswordManager(); pm.createUsersTableIfNotExist(); pm.menuInterface(); //class creation //calling userInterface method } public String generatePassword(int length, boolean includeUppercase, boolean includeLowercase, boolean includeDigits, boolean includeSpecialCharacters) { String uppercaseChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"; String lowercaseChars = "abcdefghijklmnopqrstuvwxyz"; String digitChars = "0123456789"; String specialChars = "!@#$%^&*()_-+=<>?/{}[]"; StringBuilder availableCharsBuilder = new StringBuilder(); StringBuilder passwordBuilder = new StringBuilder(); Random random = new Random(); if (includeUppercase) { availableCharsBuilder.append(uppercaseChars); passwordBuilder.append(uppercaseChars.charAt(random.nextInt(uppercaseChars.length()))); } if (includeLowercase) { availableCharsBuilder.append(lowercaseChars); passwordBuilder.append(lowercaseChars.charAt(random.nextInt(lowercaseChars.length()))); } if (includeDigits) { availableCharsBuilder.append(digitChars); passwordBuilder.append(digitChars.charAt(random.nextInt(digitChars.length()))); } if (includeSpecialCharacters) { availableCharsBuilder.append(specialChars); passwordBuilder.append(specialChars.charAt(random.nextInt(specialChars.length()))); } int availableCharsLength = availableCharsBuilder.length(); for (int i = passwordBuilder.length(); i < length; i++) { passwordBuilder.append(availableCharsBuilder.charAt(random.nextInt(availableCharsLength))); } // Shuffle the characters in the password char[] passwordChars = passwordBuilder.toString().toCharArray(); for (int i = passwordChars.length - 1; i > 0; i--) { int index = random.nextInt(i + 1); char temp = passwordChars[index]; passwordChars[index] = passwordChars[i]; passwordChars[i] = temp; } return new String(passwordChars); } } you need to derive the encryption key from the users master password
public class PasswordManager { private static final String SECRET_KEY = "Infotrixs@Key123"; private static final String ALGORITHM = "AES"; private static final String ENCODING = "UTF-8"; private Cipher cipher; private SecretKeySpec secretKey; private static Map<String, String> users = new HashMap<>(); static Scanner scanner = new Scanner(System.in); public PasswordManager() throws Exception { cipher = Cipher.getInstance(ALGORITHM); byte[] key = SECRET_KEY.getBytes(ENCODING); key = Arrays.copyOf(key, 16); //Pad key to the required 128-bit (16-byte) length secretKey = new SecretKeySpec(key, ALGORITHM); } private String encrypt(String password) throws Exception { cipher.init(Cipher.ENCRYPT_MODE, secretKey); byte[] encryptedBytes = cipher.doFinal(password.get
