Method and System for Mixed Symmetric and Asymmetric Decryption of .ZIP Files

Abstract

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 - 138 . (canceled) 
   
   
       139 . A method for providing access to data 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:
 symmetric key data; 
 asymmetric key data, wherein said symmetric key data and said asymmetric key data are stored in the central directory of said .Zip file format data container; and 
 an encrypted data file; 
   providing the options of:   (a) receiving an asymmetric key input, and   using said asymmetric key data in combination with said asymmetric key input to obtain a symmetric key to symmetrically decrypt said encrypted data file to form a decrypted data file; and   (b) receiving a symmetric key input, and   using said symmetric key data in combination with said symmetric key input to obtain a symmetric key to symmetrically decrypt said encrypted data file to form a decrypted data file; and   providing access to said decrypted data file.   
   
   
       140 . The method of  claim 139  further including decompressing said decrypted data file. 
   
   
       141 . The method of  claim 140  wherein said decompressing employs a Lempel-Ziv (LZ)-type data compression algorithm. 
   
   
       142 . The method of  claim 140  wherein said decompressing employs a Deflate-type data compression algorithm. 
   
   
       143 . The method of  claim 140  wherein said decompressing employs a Burrows-Wheeler Transform (BWT)-type data compression algorithm. 
   
   
       144 . The method of  claim 139  wherein said encrypted data file is not compressed. 
   
   
       145 . The method of  claim 139  wherein said symmetric key has a key length of at least 128 bits. 
   
   
       146 . The method of  claim 139  wherein said symmetric key has a key length of at least 192 bits. 
   
   
       147 . The method of  claim 139  wherein said symmetric key has a key length of at least 256 bits. 
   
   
       148 . The method of  claim 139  wherein said symmetrically decrypting employs an AES encryption encoding. 
   
   
       149 . The method of  claim 139  wherein said symmetrically decrypting employs a 3DES encryption encoding. 
   
   
       150 . The method of  claim 139  wherein said asymmetrically decrypting employs a private key. 
   
   
       151 . The method of  claim 139  wherein said asymmetrically decrypting employs a X.509 digital certificate. 
   
   
       152 . The method of  claim 139  wherein at least part of said decryption key is externally input. 
   
   
       153 . The method of  claim 152  wherein said at least part of said decryption key is a password. 
   
   
       154 . The method of  claim 152  wherein said at least part of said decryption key is a private key. 
   
   
       155 . The method of  claim 152  wherein at least part of said symmetric key is composed of random data.