Securing Passwords in Application Design

Oracle provides strategies for securely invoking password services, such as from scripts, and for applying these strategies to other sensitive data.

General Guidelines for Securing Passwords in Applications

Guidelines for securing passwords in applications cover areas such as platform-specific security threats.

Platform-Specific Security Threats

You should be aware of potential security threats, which may not be obvious.

These security threats are as follows:

Guidelines for Designing Applications to Handle Password Input

Oracle provides guidelines for designing applications to handle password input.

Related Topics

Guidelines for Configuring Password Formats and Behavior

Oracle Database provides guidelines for configuring password formats and behavior.

Related Topics

Guidelines for Handling Passwords in SQL Scripts

Oracle provides guidelines for handling passwords in SQL scripts.

Use of an External Password Store to Secure Passwords

You can store password credentials for connecting to a database by using a client-side Oracle wallet.

An Oracle wallet is a secure software container that stores the authentication and signing credentials needed for a user to log in.

Related Topics

Securing Passwords Using the ORAPWD Utility

SYSDBA or SYSOPER users can use password files to connect to an application over a network.

To create the password file, use the ORAPWD utility.

Related Topics

Example: Java Code for Reading Passwords

You can create Java packages that can be used to read passwords. The following example demonstrates how to create a Java package that can be used to read passwords.

// Change the following line to a name for your version of this package
package passwords.sysman.emSDK.util.signing;

import java.io.IOException;
import java.io.PrintStream;
import java.io.PushbackInputStream;
import java.util.Arrays;

/**
 * The static readPassword method in this class issues a password prompt
 * on the console output and returns the char array password
 * entered by the user on the console input.
 */
public final class ReadPassword {
  //----------------------------------
  /**
   * Test driver for readPassword method.
   * @param args the command line args
   */
  public static void main(String[] args) {
    char[] pass = ReadPassword.readPassword("Enter password: ");
    System.out.println("The password just entered is ""
      + new String(pass) + """);
    System.out.println("The password length is " + pass.length);
  }
   * Issues a password prompt on the console output and returns
   * the char array password entered by the user on the console input.
   * The password is not displayed on the console (chars are not echoed).
   * As soon as the returned char array is not needed,
   * it should be erased for security reasons (Arrays.fill(charArr, ' '));
   * A password should never be stored as a java String.
   *
   * Note that Java 6 has a Console class with a readPassword method,
   * but there is no equivalent in Java 5 or Java
1.4.
   * The readPassword method here is based on Sun's suggestions at
   * http://java.sun.com/developer/technicalArticles/Security/pwordmask.
   *
   * @param prompt the password prompt to issue
   * @return new char array containing the password
   * @throws RuntimeException if some error occurs
   */
  public static final char[] readPassword(String prompt)
  throws RuntimeException {
    try {
      StreamMasker masker = new StreamMasker(System.out, prompt);
      Thread threadMasking = new Thread(masker);
      int firstByte = -1;
      PushbackInputStream inStream = null;
      try {
        threadMasking.start();
        inStream = new PushbackInputStream(System.in);
        firstByte = inStream.read();
      } finally {
        masker.stopMasking();
      }
      try {
        threadMasking.join();
      } catch (InterruptedException e) {
        throw new RuntimeException("Interrupt occurred when reading password");
      }
      if (firstByte == -1) {
        throw new RuntimeException("Console input ended unexpectedly");
      }
      if (System.out.checkError()) {
        throw new RuntimeException("Console password prompt output error");
      }
      inStream.unread(firstByte);
      return readLineSecure(inStream);
    }
    catch (IOException e) {
      throw new RuntimeException("I/O error occurred when reading password");
    }
  }
  //----------------------------------
  /**
   * Reads one line from an input stream into a char array in a secure way
   * suitable for reading a password.
   * The char array will never contain a '\n' or '\r'.
   *
   * @param inStream the pushback input stream
   * @return line as a char array, not including end-of-line-chars;
   * never null, but may be zero length array
   * @throws RuntimeException if some error occurs
   */
  private static final char[] readLineSecure(PushbackInputStream inStream)
  throws RuntimeException {
    if (inStream == null) {
      throw new RuntimeException("readLineSecure inStream is null");
    }
    try {
      char[] buffer = null;
      try {
        buffer = new char[128];
        int offset = 0;
        // EOL is '\n' (unix), '\r\n' (windows), '\r' (mac)
        loop:
        while (true) {
          int c = inStream.read();
          switch (c) {
          case -1:
          case '\n':
            break loop;
          case '\r':
            int c2 = inStream.read();
            if ((c2 != '\n') && (c2 != -1))
              inStream.unread(c2);
            break loop;
          default:
            buffer = checkBuffer(buffer, offset);
            buffer[offset++] = (char) c;
            break;
          }
        }
        char[] result = new char[offset];
        System.arraycopy(buffer, 0, result, 0, offset);
        return result;
      }
      finally {
        if (buffer != null)
          Arrays.fill(buffer, ' ');
      }
    }
    catch (IOException e) {
      throw new RuntimeException("I/O error occurred when reading password");
    }
  }
  //----------------------------------
  /**
   * This is a helper method for readLineSecure.
   *
   * @param buffer the current char buffer
   * @param offset the current position in the buffer
   * @return the current buffer if it is not yet full;
   * otherwise return a larger buffer initialized with a copy
   * of the current buffer and then erase the current buffer
   * @throws RuntimeException if some error occurs
   */
  private static final char[] checkBuffer(char[] buffer, int offset)
  throws RuntimeException
  {
    if (buffer == null)
      throw new RuntimeException("checkBuffer buffer is null");
    if (offset < 0)
      throw new RuntimeException("checkBuffer offset is negative");
    if (offset < buffer.length)
      return buffer;
    else {
      try {
        char[] bufferNew = new char[offset + 128];
        System.arraycopy(buffer, 0, bufferNew, 0, buffer.length);
        return bufferNew;
      } finally {
        Arrays.fill(buffer, ' ');
      }
    }
  }
  //----------------------------------
  /**
   * This private class prints a one line prompt
   * and erases reply chars echoed to the console.
   */
  private static final class StreamMasker
  extends Thread {
    private static final String BLANKS = StreamMasker.repeatChars(' ', 10);
    private String m_promptOverwrite;
    private String m_setCursorToStart;
    private PrintStream m_out;
    private volatile boolean m_doMasking;
    //----------------------------------
    /**
     * Constructor.
     * @throws RuntimeException if some error occurs
     */
    public StreamMasker(PrintStream outPrint, String prompt)
    throws RuntimeException {
      if (outPrint == null)
        throw new RuntimeException("StreamMasker outPrint is null");
      if (prompt == null)
        throw new RuntimeException("StreamMasker prompt is null");
      if (prompt.indexOf('\r') != -1)
        throw new RuntimeException("StreamMasker prompt contains a CR");
      if (prompt.indexOf('\n') != -1)
        throw new RuntimeException("StreamMasker prompt contains a NL");
      m_out = outPrint;
      m_setCursorToStart = StreamMasker.repeatChars('\010',
        prompt.length() + BLANKS.length());
      m_promptOverwrite = m_setCursorToStart + prompt + BLANKS
        + m_setCursorToStart + prompt;
    }
    //----------------------------------
    /**
     * Begin masking until asked to stop.
     * @throws RuntimeException if some error occurs
     */
    public void run()
    throws RuntimeException {
      int priorityOriginal = Thread.currentThread().getPriority();
      Thread.currentThread().setPriority(Thread.MAX_PRIORITY);
      try {
        m_doMasking = true;
        while (m_doMasking) {
          m_out.print(m_promptOverwrite);
          if (m_out.checkError())
            throw new RuntimeException("Console output error writing prompt");
          try {
            Thread.currentThread().sleep(1);
          } catch (InterruptedException ie) {
            Thread.currentThread().interrupt();
            return;
          }
        }
        m_out.print(m_setCursorToStart);
      } finally {
        Thread.currentThread().setPriority(priorityOriginal);
      }
    }
    //----------------------------------
    /**
     * Instructs the thread to stop masking.
     */
    public void stopMasking() {
      m_doMasking = false;
    }
    //----------------------------------
    /**
     * Returns a repeated char string.
     *
     * @param c the char to repeat
     * @param length the number of times to repeat the char
     * @throws RuntimeException if some error occurs
     */
    private static String repeatChars(char c, int length)
    throws RuntimeException {
      if (length < 0)
        throw new RuntimeException("repeatChars length is negative");
      StringBuffer sb = new StringBuffer(length);
      for (int i = 0; i < length; i++)
        sb.append(c);
      return sb.toString();
    }
  }
}