Troubleshooting TrueCrypt PasswordDialog Errors

Customizing the TrueCrypt PasswordDialog AppearanceTrueCrypt was a widely used open-source disk encryption software that provided robust encryption features for creating and managing encrypted volumes. Although TrueCrypt development ceased in 2014 and users were encouraged to migrate to maintained alternatives (such as VeraCrypt), many users and legacy systems still interact with TrueCrypt containers. One of the UI components users sometimes want to adjust is the PasswordDialog — the window where a user types the passphrase to mount an encrypted volume. This article explains what aspects of the TrueCrypt PasswordDialog can be customized (within the limits of the original TrueCrypt codebase), how to safely apply visual or functional tweaks, and offers guidance on alternatives and modern replacements.

Overview: What the PasswordDialog Is and Why Customize It

The PasswordDialog is the modal dialog presented by TrueCrypt when a user attempts to mount a container or volume. It collects the passphrase, optional keyfiles, and mount options such as mounting as read-only or using system favorites. Customization requests generally fall into two categories:

• Cosmetic/UI changes: altering appearance (fonts, colors, control layout) to match a user’s preferences or accessibility needs.
• Functional tweaks: adding features like password reveal toggles, different input behaviors, or accessibility enhancements.

Because TrueCrypt is discontinued, customizing it requires working with the original source or using wrapper applications. Direct modification of executables can create security risks, so always prioritize safety and verification.

Before You Begin: Warnings and Preparations

• Security first: Modifying an encryption application’s UI can introduce vulnerabilities. Only modify software if you have the source code and can review changes. Avoid downloading modified binaries from untrusted sources.
• Use source-based changes: If you plan to edit TrueCrypt’s behavior, obtain the official source archive and compile it locally. This ensures you can audit changes.
• Consider alternatives: VeraCrypt is an actively maintained fork of TrueCrypt with improved security and ongoing development. Many customization needs can be met using VeraCrypt or third-party front-ends.
• Backup your volumes and essential data before testing any modified build.

Where to Find the Relevant Code

TrueCrypt’s GUI is written in C++ using the Win32 API and custom UI code (for Windows builds). The PasswordDialog implementation resides in the GUI source files, typically named something like PasswordDlg.cpp/h or PasswordDialog.*. When working from source:

1. Search for dialog resource IDs in .rc resource files.
2. Locate the dialog class handling password input, message handling, and control initialization.
3. Identify where strings for labels, tooltips, and button captions are defined (resource strings or inlined).

Cosmetic Customizations

Below are common cosmetic changes and where to apply them.

• Fonts and sizes

  • Modify the dialog resource (.rc) to change the font face and size used by controls.
  • Alternatively, set fonts at runtime in the dialog’s WM_INITDIALOG handler with CreateFont/CreateFontIndirect and SendMessage(hWndCtrl, WM_SETFONT…).

• Colors and background

  • The Win32 dialog background color can be changed by handling WM_CTLCOLORSTATIC and WM_CTLCOLORDLG messages, returning brushes created with CreateSolidBrush.
  • For more advanced visuals (gradients, images), handle WM_PAINT and draw directly using GDI/GDI+.

• Icons and graphics

  • Replace or add icons in the resource file and set them on controls or the dialog using SendMessage with STM_SETIMAGE or SetClassLongPtr for the window icon.

• Layout adjustments

  • Edit the dialog’s resource coordinates to reposition controls.
  • For dynamic layouts, implement resizing logic in WM_SIZE to reposition controls based on client area.

• Localization and strings

  • Update resource string tables for different languages.
  • Ensure UTF-8/Unicode handling by compiling with Unicode settings and using wide-character APIs.

Functional Tweaks

• Show/Hide password toggle

  • Modify the edit control style between ES_PASSWORD and normal using SetWindowLongPtr and REDRAW to toggle masked input.
  • Add a checkbox or button labeled “Show password” and handle its click to switch styles.

• Password strength meter

  • Add a custom control or progress bar that updates as the user types. Use the EN_CHANGE notification to re-evaluate strength and update the meter.

• Clipboard and paste behavior

  • Control paste actions by handling WM_PASTE or subclassing the edit control to intercept WM_SETTEXT/EM_REPLACESEL.
  • Be cautious: enabling clipboard reduces security; consider warning users.

• Keyfile UI improvements

  • Allow drag-and-drop of keyfiles onto the dialog by enabling drag-drop and processing dropped file paths.
  • Add a file picker that remembers last-used directories.

• Accessibility

  • Ensure controls have accessible names and labels; implement MSAA/UIAutomation support in code where missing.
  • Increase keyboard focus order and add accelerators.

Example: Implementing a “Show Password” Toggle (High-level)

1. Add a checkbox control to the dialog resource labeled “Show password”.
2. In WM_INITDIALOG, get the handle to the password edit control and store it.
3. On BN_CLICKED for the checkbox, call:
   • GetWindowLongPtr(hEdit, GWL_STYLE); modify to remove/add ES_PASSWORD.
   • InvalidateRect(hEdit, NULL, TRUE) and SetFocus as needed.
   • For Unicode builds, ensure to use SetWindowLongPtrW.

Security note: Briefly revealing passwords may expose them to shoulder-surfing or screen capture; consider adding an option to auto-hide after a timeout.

Recompiling and Testing

• Use the provided project files (Visual Studio solutions) in the source package.
• Build in a controlled environment (VM) and sign binaries if distributing internally.
• Test with non-critical volumes first. Verify mount/unmount behavior, keyfile handling, and any changes to entropy or encryption logic did not occur.
• Run static analysis and code scanning tools to ensure no vulnerabilities were introduced.

Alternatives to Modifying TrueCrypt

• VeraCrypt: actively maintained fork with security fixes; source is available and more modern, making customization safer.
• Front-end wrappers: build a small separate GUI that collects the password and invokes TrueCrypt/VeraCrypt command-line tools; this avoids modifying the encryption binary itself.
• Accessibility tools: use OS-level accessibility options (high-contrast themes, larger fonts) instead of editing source.

Security and Maintenance Considerations

• Never distribute modified encryption binaries publicly unless you can justify security and provide source code.
• Maintain a changelog for any UI/security adjustments.
• Periodically review changes against upstream security advisories; backport fixes if staying on TrueCrypt codebase.

Conclusion

Customizing the TrueCrypt PasswordDialog appearance and behavior is feasible if you work from source and follow secure practices. For most users, using VeraCrypt or a front-end wrapper is a safer and more maintainable approach. If you choose to modify the original TrueCrypt code, compile and test in isolated environments, prioritize code audits, and avoid sharing unsigned modified binaries.

If you want, I can:

• show sample code snippets for a specific tweak (for example the show-password toggle),
• outline a simple wrapper GUI that launches TrueCrypt/VeraCrypt, or
• give step-by-step compilation instructions for the TrueCrypt source (Windows or Linux). Which would you prefer?