|
| 1 | +# Import Libraries |
| 2 | +from PyPDF4 import PdfFileReader, PdfFileWriter, utils |
| 3 | +import os |
| 4 | +import argparse |
| 5 | +import getpass |
| 6 | +from io import BytesIO |
| 7 | +import pyAesCrypt |
| 8 | + |
| 9 | +# Size of chunck |
| 10 | +BUFFER_SIZE = 64*1024 |
| 11 | + |
| 12 | + |
| 13 | +def is_encrypted(input_file: str) -> bool: |
| 14 | + """Checks if the inputted file is encrypted using PyPDF4 library""" |
| 15 | + with open(input_file, 'rb') as pdf_file: |
| 16 | + pdf_reader = PdfFileReader(pdf_file, strict=False) |
| 17 | + return pdf_reader.isEncrypted |
| 18 | + |
| 19 | + |
| 20 | +def encrypt_pdf(input_file: str, password: str): |
| 21 | + """ |
| 22 | + Encrypts a file using PyPDF4 library. |
| 23 | + Precondition: File is not encrypted. |
| 24 | + """ |
| 25 | + pdf_writer = PdfFileWriter() |
| 26 | + pdf_reader = PdfFileReader(open(input_file, 'rb'), strict=False) |
| 27 | + if pdf_reader.isEncrypted: |
| 28 | + print(f"PDF File {input_file} already encrypted") |
| 29 | + return False, None, None |
| 30 | + try: |
| 31 | + # To encrypt all the pages of the input file, you need to loop over all of them |
| 32 | + # and to add them to the writer. |
| 33 | + for page_number in range(pdf_reader.numPages): |
| 34 | + pdf_writer.addPage(pdf_reader.getPage(page_number)) |
| 35 | + except utils.PdfReadError as e: |
| 36 | + print(f"Error reading PDF File {input_file} = {e}") |
| 37 | + return False, None, None |
| 38 | + # The default is 128 bit encryption (if false then 40 bit encryption). |
| 39 | + pdf_writer.encrypt(user_pwd=password, owner_pwd=None, use_128bit=True) |
| 40 | + return True, pdf_reader, pdf_writer |
| 41 | + |
| 42 | + |
| 43 | +def decrypt_pdf(input_file: str, password: str): |
| 44 | + """ |
| 45 | + Decrypts a file using PyPDF4 library. |
| 46 | + Precondition: A file is already encrypted |
| 47 | + """ |
| 48 | + pdf_reader = PdfFileReader(open(input_file, 'rb'), strict=False) |
| 49 | + if not pdf_reader.isEncrypted: |
| 50 | + print(f"PDF File {input_file} not encrypted") |
| 51 | + return False, None, None |
| 52 | + pdf_reader.decrypt(password=password) |
| 53 | + pdf_writer = PdfFileWriter() |
| 54 | + try: |
| 55 | + for page_number in range(pdf_reader.numPages): |
| 56 | + pdf_writer.addPage(pdf_reader.getPage(page_number)) |
| 57 | + except utils.PdfReadError as e: |
| 58 | + print(f"Error reading PDF File {input_file} = {e}") |
| 59 | + return False, None, None |
| 60 | + return True, pdf_reader, pdf_writer |
| 61 | + |
| 62 | + |
| 63 | +def cipher_stream(inp_buffer: BytesIO, password: str): |
| 64 | + """Ciphers an input memory buffer and returns a ciphered output memory buffer""" |
| 65 | + # Initialize output ciphered binary stream |
| 66 | + out_buffer = BytesIO() |
| 67 | + inp_buffer.seek(0) |
| 68 | + # Encrypt Stream |
| 69 | + pyAesCrypt.encryptStream(inp_buffer, out_buffer, password, BUFFER_SIZE) |
| 70 | + out_buffer.seek(0) |
| 71 | + return out_buffer |
| 72 | + |
| 73 | + |
| 74 | +def decipher_file(input_file: str, output_file: str, password: str): |
| 75 | + """ |
| 76 | + Deciphers an input file and returns a deciphered output file |
| 77 | + """ |
| 78 | + inpFileSize = os.stat(input_file).st_size |
| 79 | + out_buffer = BytesIO() |
| 80 | + with open(input_file, mode='rb') as inp_buffer: |
| 81 | + try: |
| 82 | + # Decrypt Stream |
| 83 | + pyAesCrypt.decryptStream( |
| 84 | + inp_buffer, out_buffer, password, BUFFER_SIZE, inpFileSize) |
| 85 | + except Exception as e: |
| 86 | + print("Exception", str(e)) |
| 87 | + return False |
| 88 | + inp_buffer.close() |
| 89 | + if out_buffer: |
| 90 | + with open(output_file, mode='wb') as f: |
| 91 | + f.write(out_buffer.getbuffer()) |
| 92 | + f.close() |
| 93 | + return True |
| 94 | + |
| 95 | + |
| 96 | +def encrypt_decrypt_file(**kwargs): |
| 97 | + """Encrypts or decrypts a file""" |
| 98 | + input_file = kwargs.get('input_file') |
| 99 | + password = kwargs.get('password') |
| 100 | + output_file = kwargs.get('output_file') |
| 101 | + action = kwargs.get('action') |
| 102 | + # Protection Level |
| 103 | + # Level 1 --> Encryption / Decryption using PyPDF4 |
| 104 | + # Level 2 --> Encryption and Ciphering / Deciphering and Decryption |
| 105 | + level = kwargs.get('level') |
| 106 | + if not output_file: |
| 107 | + output_file = input_file |
| 108 | + if action == "encrypt": |
| 109 | + result, pdf_reader, pdf_writer = encrypt_pdf( |
| 110 | + input_file=input_file, password=password) |
| 111 | + # Encryption completed successfully |
| 112 | + if result: |
| 113 | + output_buffer = BytesIO() |
| 114 | + pdf_writer.write(output_buffer) |
| 115 | + pdf_reader.stream.close() |
| 116 | + if level == 2: |
| 117 | + output_buffer = cipher_stream(output_buffer, password=password) |
| 118 | + with open(output_file, mode='wb') as f: |
| 119 | + f.write(output_buffer.getbuffer()) |
| 120 | + f.close() |
| 121 | + elif action == "decrypt": |
| 122 | + if level == 2: |
| 123 | + decipher_file(input_file=input_file, |
| 124 | + output_file=output_file, password=password) |
| 125 | + result, pdf_reader, pdf_writer = decrypt_pdf( |
| 126 | + input_file=input_file, password=password) |
| 127 | + # Decryption completed successfully |
| 128 | + if result: |
| 129 | + output_buffer = BytesIO() |
| 130 | + pdf_writer.write(output_buffer) |
| 131 | + pdf_reader.stream.close() |
| 132 | + with open(output_file, mode='wb') as f: |
| 133 | + f.write(output_buffer.getbuffer()) |
| 134 | + f.close() |
| 135 | + |
| 136 | + |
| 137 | + |
| 138 | +class Password(argparse.Action): |
| 139 | + """ |
| 140 | + Hides the password entry |
| 141 | + """ |
| 142 | + def __call__(self, parser, namespace, values, option_string): |
| 143 | + if values is None: |
| 144 | + values = getpass.getpass() |
| 145 | + setattr(namespace, self.dest, values) |
| 146 | + |
| 147 | + |
| 148 | +def is_valid_path(path): |
| 149 | + """Validates the path inputted and checks whether it is a file path or a folder path""" |
| 150 | + if not path: |
| 151 | + raise ValueError(f"Invalid Path") |
| 152 | + if os.path.isfile(path): |
| 153 | + return path |
| 154 | + elif os.path.isdir(path): |
| 155 | + return path |
| 156 | + else: |
| 157 | + raise ValueError(f"Invalid Path {path}") |
| 158 | + |
| 159 | + |
| 160 | +def parse_args(): |
| 161 | + """Get user command line parameters""" |
| 162 | + parser = argparse.ArgumentParser(description="These options are available") |
| 163 | + parser.add_argument("file", help="Input PDF file you want to encrypt", type=is_valid_path) |
| 164 | + # parser.add_argument('-i', '--input_path', dest='input_path', type=is_valid_path, |
| 165 | + # required=True, help="Enter the path of the file or the folder to process") |
| 166 | + parser.add_argument('-a', '--action', dest='action', choices=[ |
| 167 | + 'encrypt', 'decrypt'], type=str, default='encrypt', help="Choose whether to encrypt or to decrypt") |
| 168 | + parser.add_argument('-l', '--level', dest='level', choices=[ |
| 169 | + 1, 2], type=int, default=1, help="Choose which protection level to apply") |
| 170 | + parser.add_argument('-p', '--password', dest='password', action=Password, |
| 171 | + nargs='?', type=str, required=True, help="Enter a valid password") |
| 172 | + parser.add_argument('-o', '--output_file', dest='output_file', |
| 173 | + type=str, help="Enter a valid output file") |
| 174 | + args = vars(parser.parse_args()) |
| 175 | + # To Display Command Arguments Except Password |
| 176 | + print("## Command Arguments #################################################") |
| 177 | + print("\n".join("{}:{}".format(i, j) |
| 178 | + for i, j in args.items() if i != 'password')) |
| 179 | + print("######################################################################") |
| 180 | + return args |
| 181 | + |
| 182 | + |
| 183 | +if __name__ == '__main__': |
| 184 | + # Parsing command line arguments entered by user |
| 185 | + args = parse_args() |
| 186 | + # Encrypting or Decrypting File |
| 187 | + encrypt_decrypt_file( |
| 188 | + input_file=args['file'], password=args['password'], |
| 189 | + action=args['action'], level=args['level'], output_file=args['output_file'] |
| 190 | + ) |
0 commit comments