First Run

Database.java

@@ -0,0 +1,72 @@
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.Statement;
+
+public abstract class Database{
+
+  // add the username and password pair to the database
+  public static void addUsernameAndPasswordToDatabase(String username, String password) throws Exception{
+    Class.forName("org.sqlite.JDBC");
+    Connection conn = DriverManager.getConnection("jdbc:sqlite:pass_hash.db");
+
+    PreparedStatement statement = conn.prepareStatement("insert into passwords values (?, ?);");
+    statement.setString(1, username);
+    statement.setString(2, password);
+    statement.addBatch();
+
+    conn.setAutoCommit(false);
+    statement.executeBatch();
+    conn.setAutoCommit(true);
+
+    conn.close();
+  }
+
+  // create the database and tables if they don't already exist
+  public static void createDatabase() throws Exception{
+    Class.forName("org.sqlite.JDBC");
+    Connection conn = DriverManager.getConnection("jdbc:sqlite:pass_hash.db");
+    Statement stat = conn.createStatement();
+    stat.executeUpdate("create table if not exists passwords (username, password);");    
+    conn.close();
+  }
+
+  public static String[][] getAllUsernameAndPasswordPairs() throws Exception{
+    int numRows = Database.numRowsInDB();
+    String result[][] = new String[numRows][2];    
+    int index = 0;
+
+    Class.forName("org.sqlite.JDBC");
+    Connection conn = DriverManager.getConnection("jdbc:sqlite:pass_hash.db");
+    Statement stat = conn.createStatement();
+
+    ResultSet rs = stat.executeQuery("select * from passwords;");
+
+    while (rs.next() && index<numRows){
+      result[index][0] = rs.getString("username");
+      result[index][1] = rs.getString("password");
+      index++;
+    }
+
+    rs.close();
+    conn.close();
+
+    return result;
+  }
+
+  public static int numRowsInDB() throws Exception{
+    Class.forName("org.sqlite.JDBC");
+    Connection conn = DriverManager.getConnection("jdbc:sqlite:pass_hash.db");
+    Statement stat = conn.createStatement();
+    ResultSet rs = stat.executeQuery("select count(*) from passwords;");
+
+    int result = rs.getInt(1);
+
+    rs.close();
+    conn.close();
+
+    return result;
+  }
+}

DatabaseTester.java

@@ -0,0 +1,54 @@
+/* This class simply uses the other classes to take in the username/password
+ * and show how everything works.
+ */
+
+import java.util.Scanner;
+
+public class DatabaseTester{
+  public static void main(String[] args) throws Exception{
+    Scanner keyboard = new Scanner(System.in);
+    System.out.println("DatabaseTester - Let's encrypt and store some words");
+
+    System.out.print("Enter your username: ");
+    String username = keyboard.nextLine();
+
+    System.out.print("Enter your password: ");
+    String password = keyboard.nextLine();
+
+    System.out.println("Your username: " + username + "\nYour password: " + password);
+
+    // the Password class automatically encrypts the password when you instantiate it
+    // the constructor takes a string
+    Password passwd = new Password(password);
+
+    // Password's toString method returns the encrypted password
+    System.out.println("Your encrypted password: " + passwd);
+
+    // This is how you decrypt the password stored in the object
+    System.out.println("Your decrypted password: " + passwd.getDecryptedPassword());
+
+    // Password also has a static method to decrypt a formerly encrypyted/stored string
+    System.out.println("Your decrypted password with Password's static method: " + Password.decryptPassword(passwd.toString()));
+
+    // when we first run the program, we'll need to create the database
+    // createDatabase() only creates it if it doesn't already exist
+    // Database is abstract, so don't try to instantiate it
+    Database.createDatabase();
+
+    // to add a username and password to the database, just use this method
+    Database.addUsernameAndPasswordToDatabase(username, passwd.toString());
+
+    // this method will return all the rows of the database in a 2-dimensional array
+    String passwords[][] = Database.getAllUsernameAndPasswordPairs();
+
+    // this just prints the pairs
+    System.out.println("Here's all the pairs in the database!!");
+    for(int i=0; i<passwords.length; i++){
+      for(int j=0; j<passwords[i].length; j++){
+        System.out.print(passwords[i][j] + " ");
+      }
+      System.out.print("\n");
+    }
+
+  }
+}

Password.java

@@ -0,0 +1,35 @@
+/* This class encrypts a password upon object creation and 
+ * can decrypt it as well. It also decrypts a string.
+ */
+
+import org.jasypt.util.text.*;
+
+public class Password{
+  private String password;
+  private static final String ENCRYPTOR_PASSWORD = "passhash and kittens 4ever";
+  private BasicTextEncryptor encryptor = new BasicTextEncryptor();
+
+  public Password(String newPassword){
+    encryptor.setPassword(ENCRYPTOR_PASSWORD);
+    String encryptedPassword = encryptor.encrypt(newPassword);
+    password = encryptedPassword;
+  }
+
+  public String getDecryptedPassword(){
+    return (String) encryptor.decrypt(this.password);
+  }
+
+  public String getEncryptedPassword(){
+    return (String) password;
+  }
+
+  public String toString(){
+    return (String) this.getEncryptedPassword();
+  }
+
+  public static String decryptPassword(String encryptedPassword){
+    BasicTextEncryptor encryptor2 = new BasicTextEncryptor();
+    encryptor2.setPassword(ENCRYPTOR_PASSWORD);
+    return (String) encryptor2.decrypt(encryptedPassword);
+  }
+}