pdf

1#!/usr/bin/env python32"""Encrypt or decrypt a PDF with passwords (AES-256 via pypdf).3 4Note: permission flags set at encryption time are advisory — viewers may honor5them, but any PDF library can strip them. Only the user password gates content.6"""7from __future__ import annotations8 9import argparse10import json11import sys12 13 14def main() -> int:15    for stream in (sys.stdout, sys.stderr):16        try:17            stream.reconfigure(encoding="utf-8")18        except Exception:19            pass20    parser = argparse.ArgumentParser(description="Encrypt/decrypt PDFs (pypdf, AES-256).")21    parser.add_argument("pdf", help="Input PDF path")22    parser.add_argument("-o", "--output", required=True, help="Output PDF path")23    mode = parser.add_mutually_exclusive_group(required=True)24    mode.add_argument("--encrypt", action="store_true", help="Encrypt the PDF")25    mode.add_argument("--decrypt", action="store_true", help="Remove encryption (password required)")26    parser.add_argument("--user-password", help="User (open) password for --encrypt")27    parser.add_argument("--owner-password", help="Owner password for --encrypt (defaults to user password)")28    parser.add_argument("--password", help="Known password for --decrypt")29    args = parser.parse_args()30 31    try:32        from pypdf import PdfReader, PdfWriter33    except ImportError:34        print("Missing dependency: install with 'python3 -m pip install pypdf'", file=sys.stderr)35        return 236 37    reader = PdfReader(args.pdf)38    if args.encrypt:39        if not args.user_password:40            print("Error: --encrypt requires --user-password", file=sys.stderr)41            return 242        if reader.is_encrypted:43            print("Error: input already encrypted; decrypt first", file=sys.stderr)44            return 345        writer = PdfWriter()46        writer.append(reader)47        writer.encrypt(48            user_password=args.user_password,49            owner_password=args.owner_password or args.user_password,50            algorithm="AES-256",51        )52        action = "encrypted"53    else:54        if not reader.is_encrypted:55            print("Error: input is not encrypted", file=sys.stderr)56            return 357        if args.password is None or not reader.decrypt(args.password):58            print("Error: wrong or missing --password", file=sys.stderr)59            return 460        writer = PdfWriter()61        writer.append(reader)62        action = "decrypted"63 64    with open(args.output, "wb") as fh:65        writer.write(fh)66    print(json.dumps({"output": args.output, "action": action, "page_count": len(reader.pages)}))67    return 068 69 70if __name__ == "__main__":71    sys.exit(main())72