Method and system for decryption of file characteristics of .ZIP files
The present invention provides a method of integrating existing strong encryption methods into the processing of a .ZIP file to provide a highly secure data container which provides flexibility in the use of symmetric and asymmetric encryption technology. The present invention adapts the well established .ZIP file format to support higher levels of security and multiple methods of data encryption and key management, thereby producing a highly secure and flexible digital container for electronically storing and transferring confidential data
1 . A method of providing access to a file characteristic of a data file in a .Zip file format data container, said method including:
receiving a data container constructed in accordance with a .Zip file format, said data container including:
a data file; and
an encrypted file characteristic of said data file;
decrypting said encrypted file characteristic to form a decrypted file characteristic; and
providing access to said data file and said decrypted file characteristic.
2 . The method of claim 1 wherein said encrypted file characteristic is symmetrically decrypted using a symmetric key.
3 . The method of claim 2 wherein at least part of said symmetric key is composed of random data.
4 . The method of claim 2 wherein at least part of said symmetric key is input by a user
5 . The method of claim 4 wherein said at least part of said symmetric key is a password.
6 . The method of claim 2 wherein said symmetric key has a key length of at least 128 bits.
7 . The method of claim 2 wherein said symmetric key has a key length of at least 192 bits.
8 . The method of claim 2 wherein said symmetric key has a key length of at least 256 bits.
9 . The method of claim 2 wherein said at least one file characteristic is symmetrically decrypted using an AES decryption decoding.
10 . The method of claim 2 wherein said at least one file characteristic is symmetrically decrypted using a 3DES decryption decoding.
11 . The method of claim 1 wherein said at least one file characteristic is asymmetrically decrypted.
12 . The method of claim 12 wherein said asymmetric decryption employs a private key.
13 . The method of claim 12 wherein said asymmetric decryption employs a X.509 digital certificate.
14 . The method of claim 1 including a plurality of file characteristics.
15 . The method of claim 14 wherein not all of said plurality of file characteristics are decrypted.
16 . The method of claim 14 wherein at least one of said plurality of file characteristics is decrypted using a first type of decryption and at least one of said plurality of file characteristics is decrypted using a second type of decryption.
17 . The method of claim 16 wherein a first of said plurality of file characteristics is decrypted using a first symmetric decryption and a second of said plurality of file characteristics is decrypted using a second symmetric decryption different from said first symmetric decryption.
18 . The method of claim 17 wherein said first symmetric decryption employs a key having a first key length and said second symmetric decryption employs a key having a second key length different from said first key length.
19 . The method of claim 16 wherein a first of said plurality of file characteristics is decrypted using a first asymmetric decryption and a second of said plurality of file characteristics is decrypted using a second asymmetric decryption different from said first asymmetric encryption.
20 . The method of claim 1 wherein said at least one file characteristic includes the name of said data file.
21 . The method of claim 1 wherein said at least one file characteristic includes the size of said data file.
22 . The method of claim 1 wherein said at least one file characteristic includes the creation date of said data file
23 . The method of claim 1 wherein said at least one file characteristic includes the creation time of said data file.
24 . The method of claim 1 further including decrypting said data file.
25 . The method of claim 24 wherein said data file is decrypted using symmetric decryption.
26 . The method of claim 24 wherein said data file is decrypted using asymmetric decryption.
27 . The method of claim 24 further including decompressing said file characteristic after decrypting said file characteristic.
28 . The method of claim 27 wherein said data file is decompressed using a Lempel-Ziv (LZ)-type data decompression algorithm.
29 . The method of claim 27 wherein said data file is decompressed using a Deflate-type data decompression algorithm.
30 . The method of claim 27 wherein said data file is decompressed using a Burrows-Wheeler Transform (BWT)-type data decompression algorithm.
31 . The method of claim 24 wherein said data file is not decompressed.
32 . The method of claim 1 further including decompressing said file characteristic.
33 . A method of providing access to a file characteristic of a data file in a data container, said method including:
receiving a data container designed for containing compressed file, said data container including:
a data file; and
an encrypted file characteristic of said data file;
decrypting said encrypted file characteristic to form a decrypted file characteristic; and
providing access to said data file and said decrypted file characteristic.
34 . The method of claim 33 wherein said encrypted file characteristic is symmetrically decrypted using a symmetric key.
35 . The method of claim 34 wherein at least part of said symmetric key is composed of random data.
36 . The method of claim 34 wherein at least part of said symmetric key is input by a user
37 . The method of claim 36 wherein said at least part of said symmetric key is a password.
38 . The method of claim 34 wherein said symmetric key has a key length of at least 128 bits.
39 . The method of claim 34 wherein said symmetric key has a key length of at least 192 bits.
40 . The method of claim 34 wherein said symmetric key has a key length of at least 256 bits.
41 . The method of claim 34 wherein said at least one file characteristic is symmetrically decrypted using an AES decryption decoding.
42 . The method of claim 34 wherein said at least one file characteristic is symmetrically decrypted using a 3DES decryption decoding.
43 . The method of claim 33 wherein said at least one file characteristic is asymmetrically decrypted.
44 . The method of claim 43 wherein said asymmetric decryption employs a private key.
45 . The method of claim 43 wherein said asymmetric decryption employs a X.509 digital certificate.
46 . The method of claim 33 including a plurality of file characteristics.
47 . The method of claim 46 wherein not all of said plurality of file characteristics are decrypted.
48 . The method of claim 46 wherein at least one of said plurality of file characteristics is decrypted using a first type of decryption and at least one of said plurality of file characteristics is decrypted using a second type of decryption.
49 . The method of claim 48 wherein a first of said plurality of file characteristics is decrypted using a first symmetric decryption and a second of said plurality of file characteristics is decrypted using a second symmetric decryption different from said first symmetric decryption.
50 . The method of claim 49 wherein said first symmetric decryption employs a key having a first key length and said second symmetric decryption employs a key having a second key length different from said first key length.
51 . The method of claim 48 wherein a first of said plurality of file characteristics is decrypted using a first asymmetric decryption and a second of said plurality of file characteristics is decrypted using a second asymmetric decryption different from said first asymmetric encryption.
52 . The method of claim 33 wherein said at least one file characteristic includes the name of said data file.
53 . The method of claim 33 wherein said at least one file characteristic includes the size of said data file.
54 . The method of claim 33 wherein said at least one file characteristic includes the creation date of said data file
55 . The method of claim 33 wherein said at least one file characteristic includes the creation time of said data file.
56 . The method of claim 33 further including decrypting said data file.
57 . The method of claim 56 wherein said data file is decrypted using symmetric decryption.
58 . The method of claim 56 wherein said data file is decrypted using asymmetric decryption.
59 . The method of claim 56 further including decompressing said file characteristic after decrypting said file characteristic.
60 . The method of claim 59 wherein said data file is decompressed using a Lempel-Ziv (LZ)-type data decompression algorithm.
61 . The method of claim 59 wherein said data file is decompressed using a Deflate-type data decompression algorithm.
62 . The method of claim 59 wherein said data file is decompressed using a Burrows-Wheeler Transform (BWT)-type data decompression algorithm.
63 . The method of claim 57 wherein said data file is not decompressed.
64 . The method of claim 33 further including decompressing said file characteristic.
65 . The method of claim 33 wherein said data container is constructed in accordance with a .Zip file format.