S8m7iAEL

1import os, random, struct, sys
2from Cryptodome.Cipher import AES
3
4
5def decrypt_file(key, input_file):
6    """ Decrypts a file using AES CBC mode with the
7        given key.
8    """
9
10    # This the block size of data we read, decrypt and write.
11    # It should be a multiple of 16 for AES.
12    chunksize=16*4*1024
13
14    # get rid of the .aes ending
15    output_filename = os.path.splitext(input_file)[0]
16
17    try:
18        with open(input_file, 'rb') as in_file:
19            # retrieve the original size of the encrypted data
20            original_size = struct.unpack('<Q', in_file.read(struct.calcsize('Q')))[0]
21            # retrieve the initialization vector
22            initial_vector = in_file.read(16)
23            decryptor = AES.new(key, AES.MODE_CBC, initial_vector)
24
25            # read block for block the encrypted data, decrypt and write
26            # sometimes decrypted files are already in place and
27            # in use by the system and not writeable e.g. Thumbs.db
28            try:
29                with open(output_filename, 'wb') as out_file:
30                    while True:
31                        chunk = in_file.read(chunksize)
32                        if len(chunk) == 0:
33                            break
34                        out_file.write(decryptor.decrypt(chunk))
35                    # restore original size
36                    out_file.truncate(original_size)
37            except PermissionError:
38                print("\nCouldn't write ", output_filename)
39    except PermissionError:
40        print("\nCouldn't read ", input_file)
41
42def main():
43    #secret_key = b'--> I am a random secret key <--'
44
45    secret_key = input("Give me your secret key (16, 24 or 32 characters):").encode("utf-8")
46    while len(secret_key) != 16 and len(secret_key) != 24 and len(secret_key) != 32:
47        print("\nThere was an error! Please try again with 16, 24 or 32 characters:")
48        secret_key = input("\nGive me your secret key (16, 24 or 32 characters):").encode("utf-8")
49
50    path = input("\nGive me a path or file to decrypt:")
51    while os.path.isdir(path) != True and os.path.isfile(path) != True:
52        print("\nThere was an error! Please try again with a correct path or file to decrypt:")
53        path = input("\nGive me a path or file to decrypt:")
54
55    # path = directory?
56    if os.path.isdir(path):
57        files = []
58        # traverse all subfolders and save path + filename
59        for root, d_names, f_names in os.walk(path):
60            for f in f_names:
61                files.append(os.path.join(root, f))  # these are all files in all subfolders
62        for file in files:
63            # better skip not encrypted files
64            if file.endswith(".aes"):
65                print("\nDecrypting ", file)
66                decrypt_file(secret_key, file)
67                # after decryption we could delete the file.. ;)
68                # just remove the '#' in the next line
69                #os.remove(file)
70
71    # path is no directory, but must be a file
72    else:
73        # better skip not encrypted files + dirty fix
74        if path.endswith(".aes") and not path.endswith("Thumbs.db.aes"):
75            print("\nDecrypting ", path)
76            decrypt_file(secret_key, path)
77            # after decryption we could delete the file.. ;)
78            # but think about typing in the wrong key...
79            # just remove the '#' in the next line
80            #os.remove(path)
81
82if __name__ == '__main__':
83    main()