A 32-bit C++ Authentication System Powered by Inline x86 Assembly
The Secure Login System — C++ & x86 Assembly is a console-based authentication application developed for the Computer Organization and Assembly Language (COAL) Lab.
The project combines the flexibility of C++ with the low-level capabilities of 32-bit x86 Assembly to create an interactive authentication environment supporting both normal users and administrators.
Rather than implementing a basic username-and-password check, the system incorporates several layers of account management, including password strength evaluation, temporary account lockouts, password expiration, recovery through security questions, login auditing, account blocking, and activity tracking.
A major technical aspect of the project is the use of 17 inline Assembly routines integrated directly into the C++ application.
At startup, the application restores previously stored user information and presents a central menu.
APPLICATION
│
▼
┌─────────────┐
│ Main Menu │
└──────┬──────┘
│
┌───────────────┼───────────────┐
│ │ │
▼ ▼ ▼
Admin Login User Login Exit
│ │
▼ ▼
Admin Dashboard User Menu
│
┌─────────────┼─────────────┐
▼ ▼ ▼
Login Register Recovery
│
▼
User Dashboard
│
┌────────┼────────┐
▼ ▼ ▼
Profile Settings Activity
This structure separates administrative functions from regular user operations.
The user authentication process follows several validation stages.
- User provides a username.
- The system searches for the corresponding account.
- Blocked accounts are rejected.
- Temporary lock status is checked.
- The password is requested.
- The credentials are compared.
- Failed attempts are counted.
- Three unsuccessful attempts trigger a temporary lock.
- Successful authentication updates login statistics.
- The user is transferred to the User Panel.
This allows authentication to interact with the account-management features instead of operating as an isolated login screen.
The project implements multiple security-oriented mechanisms.
User Account
│
├── Failed Attempt 1
│
├── Failed Attempt 2
│
└── Failed Attempt 3
│
▼
30 Second Lock
The administrator account uses a separate 10-second lockout period.
Successful logins contribute toward a password-expiry counter.
Login 1 → Normal
Login 2 → Normal
Login 3 → Normal
Login 4 → Expiry Reminder
Login 5 → Password Change Required
Administrators can manually block accounts. A blocked account cannot authenticate until an administrator removes the block.
After authentication, users have access to their own account environment.
Users can view information such as:
- Login statistics
- Failed attempts
- Last login
- Account status
- Login streak
- Password expiry information
The settings section provides:
- Change Username
- Change Password
- Delete Account
Account deletion requires both password verification and explicit confirmation by entering:
DELETE
The application calculates an activity level based on the number of successful logins.
Beginner → < 5 logins
Regular → 5–19 logins
Power User → 20+ logins
The administrator environment provides centralized account management.
ADMIN PANEL
│
├── View Total Users
├── View Total System Logins
├── View All Users
├── Search User
├── Remove User
├── Login Audit Report
├── View Login History
├── Block User
├── Unblock User
└── Return to Main Menu
The audit functionality allows the administrator to inspect user activity, failed attempts, login counts, streak information, and account status.
The most important technical aspect of this project is the integration of inline Assembly into a C++ application.
The application contains 17 Assembly routines covering several low-level operations.
| Routine | Function |
|---|---|
compareStr() |
Compares strings byte-by-byte |
addOne() |
Increments an integer |
takeOne() |
Decrements an integer |
isUpper() |
Checks uppercase characters |
isLower() |
Checks lowercase characters |
isDigit() |
Checks numeric characters |
isSpecial() |
Checks special characters |
asmStrLen() |
Calculates string length |
asmStrCopy() |
Performs string copying |
asmCheckLock() |
Evaluates lock duration |
asmBubbleSwap() |
Swaps user records |
asmBeepSuccess() |
Success audio feedback |
asmBeepError() |
Error audio feedback |
asmBeepWarning() |
Warning audio feedback |
asmCountChar() |
Counts characters |
asmStrCat() |
Concatenates strings |
asmToUpperChar() |
Converts lowercase to uppercase |
The Assembly components provide practical experience with:
EAX
EBX
ECX
EDX
ESI
EDI
LODSB
STOSB
SCASB
REPNE SCASB
REP MOVSB
INC
DEC
CMP
IMUL
IDIV
JMP
JE
JNE
JGE
JL
JG
The project therefore demonstrates how low-level instructions can contribute to actual application functionality.
The system uses a flat text file for persistent storage:
users.txt
The application loads user records during initialization and writes updated information whenever account-related changes occur.
The system is designed to support up to:
20 registered users
The stored account information includes authentication data, login statistics, lock information, timestamps, and activity history.
Password strength is evaluated using four main criteria:
┌─────────────────────────────┐
│ Password Analysis │
├─────────────────────────────┤
│ ✓ Uppercase character │
│ ✓ Lowercase character │
│ ✓ Numeric digit │
│ ✓ Special character │
└─────────────────────────────┘
The application can also generate a strong 10-character password containing:
- 2 uppercase letters
- 3 lowercase letters
- 3 digits
- 2 special characters
The generated characters are shuffled before being presented to the user.
Forgotten passwords can be recovered through the registered security question.
Username
↓
Account Verification
↓
Security Question
↓
Answer Verification
↓
New Password
↓
Strength Validation
↓
Password Updated
After a successful password reset, relevant account counters are reset.
The system maintains a rolling history containing the user's five most recent login timestamps.
It also calculates a daily login streak.
Day 1 → Login ✓
Day 2 → Login ✓
Day 3 → Login ✓
Day 4 → Login ✓
Current Streak = 4
If the user misses a day, the current streak is reset according to the application's date calculation logic.
The project uses Windows console functionality to provide:
- Color-coded output
- Menu-driven navigation
- Password masking
- Console title customization
- Audio feedback
- Screen transitions
- Interactive keyboard input
This creates a more structured experience than a conventional text-only authentication program.
| Component | Used |
|---|---|
| Programming Language | C++ |
| Low-Level Language | x86 Assembly |
| Compiler | Microsoft Visual C++ |
| IDE | Visual Studio |
| Target Architecture | 32-bit x86 |
| Operating System | Windows |
| Data Storage | users.txt |
| Interface | Console |
| Assembly Syntax | MSVC Inline __asm |
The project requires:
- Windows
- Visual Studio
- Microsoft Visual C++
- x86 / 32-bit build configuration
Note: MSVC inline Assembly is intended for 32-bit builds. Make sure the project is compiled for x86 rather than x64.
Clone the repository:
git clone https://github.com/YOUR-USERNAME/password-protected-login-system.gitOpen the project in Visual Studio.
Select:
Platform → x86
Build and run the application.
The default administrator account included by the project is:
Username: admin
Password: Admin@1234
This account is intended for demonstration and academic testing.
secure-login-system-cpp-assembly/
│
├── main.cpp
├── README.md
├── Project-Documentation.pdf
├── Main Menu.jpg
├── Admin Panel.jpg
├── User Panel.jpg
├── User Registration Panel.jpg
A detailed technical report is included with the project:
Project-Documentation.pdf
The documentation provides deeper information about the application's:
- Architecture
- Data structures
- Memory layout
- Assembly routines
- Algorithms
- Authentication modules
- Security mechanisms
- Execution flow
- Technical specifications
- Limitations
- Future development
This project was created for academic and educational purposes.
Although it demonstrates several authentication and account-protection mechanisms, it should not be considered a production-ready authentication platform.
For real-world deployment, additional security measures such as password hashing, encrypted storage, stronger recovery mechanisms, and secure database management would be required.
The project can be extended by introducing:
- Secure password hashing
- Encrypted credential storage
- Database integration
- Email/OTP-based recovery
- More advanced account monitoring
- Cross-platform support
- Improved authentication policies
- Modern 64-bit Assembly compatibility
- Additional administrator controls
This project provided practical exposure to several areas of computer science:
- C++
- Functions
- Structures
- Arrays
- File handling
- Console UI
- CPU registers
- Memory addresses
- Pointers
- Low-level data manipulation
- String instructions
- Arithmetic operations
- Conditional branching
- Register-based operations
- Memory copying
- Authentication
- Password policies
- Account lockout
- Password expiry
- Access control
- Login auditing
BS Artificial Intelligence University of Central Punjab
Built as a COAL Lab Project
C++ • x86 Assembly • Authentication • Systems Programming
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