Password security requirements - exclude commonly used words and keybord patterns

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Crafting Strong Passwords: Excluding Common Words and Keyboard Patterns

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Learn how to enforce robust password policies by programmatically excluding commonly used words, dictionary terms, and predictable keyboard patterns, significantly enhancing security.

Password security is a cornerstone of digital safety. While length and character variety are crucial, a common pitfall is the use of easily guessable words or patterns. Attackers frequently employ dictionary attacks and pattern recognition algorithms to crack passwords. This article explores how to implement password validation that goes beyond basic character requirements, focusing on excluding commonly used words and keyboard patterns to create truly resilient passwords.

The Perils of Predictable Passwords

Many users, consciously or unconsciously, create passwords that are simple to remember but equally simple to guess. This includes using common dictionary words (e.g., 'password', 'qwerty', '123456'), personal information, or sequential keyboard patterns. These choices drastically reduce the entropy of a password, making it vulnerable to automated attacks. A strong password should be unpredictable and unique, not just long.

flowchart TD
    A[User Enters Password] --> B{Check Length & Complexity?}
    B -->|No| C[Reject: Too Simple]
    B -->|Yes| D{Check Against Blacklist (Common Words)?}
    D -->|Yes| C
    D -->|No| E{Check Against Keyboard Patterns?}
    E -->|Yes| C
    E -->|No| F[Accept Password: Strong]

Password Validation Workflow with Blacklist and Pattern Checks

Implementing a Blacklist for Common Words

The most straightforward way to prevent common words is to maintain a blacklist. This list should contain frequently used passwords, dictionary words, and terms specific to your application or organization that should never be used. When a user submits a password, it should be checked against this list (case-insensitively). For larger blacklists, consider using efficient data structures like hash sets for quick lookups.

import re

def is_common_word(password, blacklist):
    password_lower = password.lower()
    for word in blacklist:
        if word.lower() in password_lower:
            return True
    return False

common_passwords = {"password", "123456", "qwerty", "admin", "user"}

# Example usage
print(is_common_word("MyPassword123", common_passwords)) # True
print(is_common_word("SecureP@ssw0rd", common_passwords)) # False

Python function to check password against a simple blacklist.

💡

For production systems, consider using publicly available password blacklists (e.g., from OWASP) and regularly updating them. Also, normalize passwords (e.g., remove spaces, replace common substitutions like 'a' with '@') before checking against the blacklist to catch more variations.

Detecting Keyboard Patterns and Sequences

Beyond dictionary words, many users resort to keyboard patterns (e.g., qwe, asd, zxc) or simple sequences (e.g., 123, abc). Detecting these requires more sophisticated logic, often involving regular expressions or custom algorithms that analyze character adjacency on a standard keyboard layout. This can be complex, but significantly improves security.

function containsKeyboardPattern(password) {
    const keyboardPatterns = [
        /qwerty/i, /asdfgh/i, /zxcvbn/i, // QWERTY rows
        /123456/i, /234567/i, /345678/i, // Number sequences
        /abcde/i, /bcdef/i, /cdefg/i, // Alphabetical sequences
        /(.)\1\1/ // Three or more repeating characters
    ];

    for (const pattern of keyboardPatterns) {
        if (pattern.test(password)) {
            return true;
        }
    }
    return false;
}

// Example usage
console.log(containsKeyboardPattern("qweRty123")); // true
console.log(containsKeyboardPattern("P@ssw0rd!")); // false

JavaScript function to detect common keyboard and sequential patterns using regular expressions.

⚠️

Overly aggressive pattern detection can lead to false positives and frustrate users. Balance strictness with usability. Consider allowing some short sequences if the overall password complexity is high.

Integrating Advanced Password Validation

To build a truly robust password policy, combine these techniques with other best practices like minimum length, character diversity (uppercase, lowercase, numbers, symbols), and disallowing personal information. The goal is to guide users towards creating passwords that are both strong and memorable, without being easily guessable by automated tools.

1. Define Blacklist

Compile a comprehensive list of common passwords, dictionary words, and application-specific terms to disallow. Store this securely and update it periodically.

2. Implement Blacklist Check

Create a function that checks a candidate password against your blacklist, performing case-insensitive comparisons and potentially normalizing the password first.

3. Develop Pattern Detection

Write functions or use regular expressions to identify common keyboard patterns, numerical sequences, alphabetical sequences, and repeating characters.

4. Combine Validation Rules

Integrate these checks into your overall password validation logic, alongside length, character type, and other security requirements.

5. Provide User Feedback

When a password fails validation, provide clear, helpful feedback to the user, explaining why it was rejected (e.g., 'Password contains a common word', 'Avoid keyboard patterns').