File Integrity Checker

[poorni286]

Here’s a clear plan and sample implementation for your File Integrity Checker in Python, as requested for your CODTECH internship task.

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Task Overview

Goal: Build a Python tool that monitors file changes by calculating and comparing hash values (using hashlib) to ensure file integrity.

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How It Works

1. Initial Hashing: Calculate and store the hashes (e.g., SHA256) of target files.
2. Monitoring: On subsequent runs, recalculate and compare hashes to detect changes.
3. Reporting: Notify if any file has changed, been deleted, or added.

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Sample Python Script: File Integrity Checker

import hashlib
import os
import json

HASH_FILE = 'file_hashes.json'  # Where hashes are stored

def get_file_hash(filename):
    """Calculate SHA256 hash of a file."""
    sha256 = hashlib.sha256()
    try:
        with open(filename, 'rb') as f:
            while chunk := f.read(8192):
                sha256.update(chunk)
        return sha256.hexdigest()
    except FileNotFoundError:
        return None

def scan_directory(directory):
    """Scan all files in the directory and get their hashes."""
    file_hashes = {}
    for root, _, files in os.walk(directory):
        for name in files:
            filepath = os.path.join(root, name)
            file_hashes[filepath] = get_file_hash(filepath)
    return file_hashes

def load_hashes():
    """Load stored file hashes."""
    if os.path.exists(HASH_FILE):
        with open(HASH_FILE, 'r') as f:
            return json.load(f)
    return {}

def save_hashes(hashes):
    """Save file hashes to disk."""
    with open(HASH_FILE, 'w') as f:
        json.dump(hashes, f, indent=2)

def compare_hashes(old_hashes, new_hashes):
    """Compare old and new hashes to find changes."""
    changed = []
    deleted = []
    added = []

    for file, old_hash in old_hashes.items():
        if file not in new_hashes:
            deleted.append(file)
        elif old_hash != new_hashes[file]:
            changed.append(file)
    for file in new_hashes:
        if file not in old_hashes:
            added.append(file)
    return changed, deleted, added

if __name__ == "__main__":
    directory = input("Enter directory to monitor: ").strip()
    current_hashes = scan_directory(directory)
    previous_hashes = load_hashes()

    changed, deleted, added = compare_hashes(previous_hashes, current_hashes)

    if not previous_hashes:
        print("Initial scan complete. Hashes saved.")
    else:
        if changed:
            print("Changed files:", *changed, sep="\n- ")
        if deleted:
            print("Deleted files:", *deleted, sep="\n- ")
        if added:
            print("Added files:", *added, sep="\n- ")
        if not (changed or deleted or added):
            print("No changes detected.")

    save_hashes(current_hashes)

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Instructions

1. Save the script (e.g., as file_integrity_checker.py).
2. Run the script:

   python file_integrity_checker.py
   

3. Enter the directory you want to monitor.
4. First run saves the baseline.
   Subsequent runs will report any changes.

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You can further enhance this script (optional):

• Email/SMS alerts
• Monitor only specific file types
• Hash only files above/below certain sizes
• Integrate with a GUI

Let me know if you need explanation or modifications!