PDF Encryption and Decryption

PDF ENC & DEC/pdf_enc_dec.py

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+# PDF Encrypter/Decrypter Application
+# Made By Soriful Islam Sk
+# Requires: pip install pypdf cryptography
+# -------------------------------------------------------------------
+
+import tkinter as tk
+from tkinter import filedialog, messagebox
+from pypdf import PdfReader, PdfWriter
+import os
+
+# --- CORE ENCRYPTION/DECRYPTION LOGIC ---
+
+def encrypt_pdf_file(input_path, output_path, user_password, owner_password):
+    """Encrypts a PDF file using AES-256 and sets permissions."""
+    try:
+        reader = PdfReader(input_path)
+        # Clone pages from reader to a new writer object
+        writer = PdfWriter(clone_from=reader) 
+
+        # Set AES-256 encryption and restrict user permissions
+        writer.encrypt(
+            user_password=user_password,
+            owner_password=owner_password,
+            permissions_flag=0xFFC0, # Common flag to restrict editing/copying for the user
+            algorithm="AES-256"
+        )
+
+        with open(output_path, "wb") as output_file:
+            writer.write(output_file)
+
+        return True, f"Encrypted and saved as:\n{output_path}"
+    except Exception as e:
+        return False, f"Encryption Error: {e}"
+
+def decrypt_pdf_file(input_path, output_path, user_password, owner_password):
+    """
+    Decrypts a password-protected PDF file by attempting the user_password 
+    first, and then falling back to the owner_password.
+    """
+    try:
+        reader = PdfReader(input_path)
+
+        if not reader.is_encrypted:
+            # If the file isn't encrypted, just save a copy and inform the user.
+            writer = PdfWriter(clone_from=reader)
+            with open(output_path, "wb") as output_file:
+                writer.write(output_file)
+            return True, f"File was not encrypted. Saved copy as:\n{output_path}"
+
+        # 1. ATTEMPT DECRYPTION WITH USER PASSWORD
+        result = reader.decrypt(user_password)
+
+        if result not in (1, 0): # 1 and 0 indicate successful decryption
+            # 2. FALLBACK: ATTEMPT DECRYPTION WITH OWNER PASSWORD
+            result = reader.decrypt(owner_password)
+
+        # 3. CHECK FINAL DECRYPTION STATUS
+        if result not in (1, 0):
+            return False, "Decryption Error: Neither the User nor the Owner password worked."
+
+        # Decryption was successful (either password worked)
+        writer = PdfWriter(clone_from=reader)
+
+        with open(output_path, "wb") as output_file:
+            writer.write(output_file)
+
+        return True, f"Decrypted and saved as:\n{output_path}"
+
+    except Exception as e:
+        return False, f"Decryption Error: {e}"
+
+# --- GUI APPLICATION CLASS ---
+
+class PDFSecurityApp:
+    def __init__(self, master):
+        self.master = master
+        master.title("PDF Encrypter/Decrypter")
+        # Increased height slightly to accommodate the new label
+        master.geometry("450x330") 
+
+        self.input_file_path = tk.StringVar()
+        self.user_pass = tk.StringVar()
+        self.owner_pass = tk.StringVar()
+
+        # 1. File Selection Section
+        tk.Label(master, text="Select PDF File:").grid(row=0, column=0, padx=10, pady=10, sticky="w")
+        self.file_entry = tk.Entry(master, textvariable=self.input_file_path, width=40)
+        self.file_entry.grid(row=0, column=1, padx=5, pady=10)
+        tk.Button(master, text="Browse", command=self.browse_file).grid(row=0, column=2, padx=5, pady=10)
+
+        # 2. Password Entry Section (User/Open Password)
+        tk.Label(master, text="User/Open Password:").grid(row=1, column=0, padx=10, pady=5, sticky="w")
+        tk.Entry(master, textvariable=self.user_pass, show="*", width=30).grid(row=1, column=1, padx=5, pady=5)
+
+        # 3. Owner/Admin Password 
+        tk.Label(master, text="Owner/Admin Password:").grid(row=2, column=0, padx=10, pady=5, sticky="w")
+        tk.Entry(master, textvariable=self.owner_pass, show="*", width=30).grid(row=2, column=1, padx=5, pady=5)
+
+        # 4. Action Buttons Section
+        button_frame = tk.Frame(master)
+        button_frame.grid(row=3, column=0, columnspan=3, pady=20)
+
+        tk.Button(button_frame, text="🔒 ENCRYPT PDF", command=self.handle_encrypt, 
+                  bg="lightblue", padx=10, pady=5).pack(side=tk.LEFT, padx=10)
+
+        tk.Button(button_frame, text="🔓 DECRYPT PDF", command=self.handle_decrypt, 
+                  bg="lightgreen", padx=10, pady=5).pack(side=tk.LEFT, padx=10)
+
+        # 5. Author Credit Label
+        tk.Label(
+            master, 
+            text="Made By Soriful Islam Sk", 
+            fg="gray", 
+            font=("Arial", 9, "italic")
+        ).grid(row=4, column=0, columnspan=3, pady=(10, 5))
+
+    def browse_file(self):
+        """Opens a dialog to select the input PDF file."""
+        file_path = filedialog.askopenfilename(
+            defaultextension=".pdf",
+            filetypes=[("PDF files", "*.pdf"), ("All files", "*.*")]
+        )
+        if file_path:
+            self.input_file_path.set(file_path)
+
+    def get_output_path(self, operation):
+        """Generates the output file path based on the operation."""
+        input_path = self.input_file_path.get()
+        if not input_path:
+            return None
+
+        base, ext = os.path.splitext(input_path)
+        default_output = f"{base}_{operation}{ext}"
+
+        return filedialog.asksaveasfilename(
+            defaultextension=ext,
+            initialfile=default_output,
+            filetypes=[("PDF files", "*.pdf")]
+        )
+
+    def handle_encrypt(self):
+        """Handles the Encrypt button click."""
+        input_path = self.input_file_path.get()
+        user_p = self.user_pass.get()
+        owner_p = self.owner_pass.get()
+
+        if not input_path or not user_p:
+            messagebox.showerror("Input Error", "Please select a file and enter a User Password.")
+            return
+
+        # Use user password as owner password if owner field is left empty
+        if not owner_p:
+            owner_p = user_p 
+
+        output_path = self.get_output_path("encrypted")
+        if not output_path:
+            return
+
+        success, message = encrypt_pdf_file(input_path, output_path, user_p, owner_p)
+
+        if success:
+            messagebox.showinfo("Success", f"Encryption Complete! {message}")
+        else:
+            messagebox.showerror("Error", message)
+
+    def handle_decrypt(self):
+        """Handles the Decrypt button click by trying both passwords."""
+        input_path = self.input_file_path.get()
+        user_p = self.user_pass.get()
+        owner_p = self.owner_pass.get()
+
+        # Check that at least one password is provided for decryption attempt
+        if not input_path or (not user_p and not owner_p):
+            messagebox.showerror(
+                "Input Error", 
+                "Please select a file and enter at least one password (User or Owner) for decryption."
+            )
+            return
+
+        output_path = self.get_output_path("decrypted")
+        if not output_path:
+            return
+
+        # Pass both entered passwords for sequential trial in the decryption function
+        success, message = decrypt_pdf_file(input_path, output_path, user_p, owner_p)
+
+        if success:
+            messagebox.showinfo("Success", f"Decryption Complete! {message}")
+        else:
+            messagebox.showerror("Error", message)
+
+
+# --- RUN THE APPLICATION ---
+if __name__ == "__main__":
+    root = tk.Tk()
+    app = PDFSecurityApp(root)
+    root.mainloop()