72 lines
2.6 KiB
Python
72 lines
2.6 KiB
Python
#!/usr/bin/env python3
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"""Encrypt or decrypt a PDF with passwords (AES-256 via pypdf).
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Note: permission flags set at encryption time are advisory — viewers may honor
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them, but any PDF library can strip them. Only the user password gates content.
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"""
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from __future__ import annotations
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import argparse
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import json
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import sys
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def main() -> int:
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for stream in (sys.stdout, sys.stderr):
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try:
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stream.reconfigure(encoding="utf-8")
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except Exception:
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pass
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parser = argparse.ArgumentParser(description="Encrypt/decrypt PDFs (pypdf, AES-256).")
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parser.add_argument("pdf", help="Input PDF path")
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parser.add_argument("-o", "--output", required=True, help="Output PDF path")
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mode = parser.add_mutually_exclusive_group(required=True)
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mode.add_argument("--encrypt", action="store_true", help="Encrypt the PDF")
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mode.add_argument("--decrypt", action="store_true", help="Remove encryption (password required)")
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parser.add_argument("--user-password", help="User (open) password for --encrypt")
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parser.add_argument("--owner-password", help="Owner password for --encrypt (defaults to user password)")
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parser.add_argument("--password", help="Known password for --decrypt")
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args = parser.parse_args()
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try:
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from pypdf import PdfReader, PdfWriter
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except ImportError:
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print("Missing dependency: install with 'python3 -m pip install pypdf'", file=sys.stderr)
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return 2
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reader = PdfReader(args.pdf)
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if args.encrypt:
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if not args.user_password:
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print("Error: --encrypt requires --user-password", file=sys.stderr)
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return 2
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if reader.is_encrypted:
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print("Error: input already encrypted; decrypt first", file=sys.stderr)
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return 3
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writer = PdfWriter()
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writer.append(reader)
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writer.encrypt(
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user_password=args.user_password,
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owner_password=args.owner_password or args.user_password,
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algorithm="AES-256",
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)
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action = "encrypted"
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else:
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if not reader.is_encrypted:
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print("Error: input is not encrypted", file=sys.stderr)
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return 3
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if args.password is None or not reader.decrypt(args.password):
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print("Error: wrong or missing --password", file=sys.stderr)
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return 4
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writer = PdfWriter()
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writer.append(reader)
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action = "decrypted"
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with open(args.output, "wb") as fh:
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writer.write(fh)
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print(json.dumps({"output": args.output, "action": action, "page_count": len(reader.pages)}))
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return 0
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if __name__ == "__main__":
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sys.exit(main())
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