Method and system for multiple asymmetric encryption of .ZIP files

• US 7,895,434 B2
• Filed: 09/20/2004
• Issued: 02/22/2011
• Est. Priority Date: 07/16/2003
• Status: Active Grant

• Current Assignee: PKWARE, Inc. (PKW Holdings, Inc.)
• Original Assignee: PKWARE, Inc. (PKW Holdings, Inc.)
• Inventors: Peterson, James C.
• Primary Examiner(s): Dinh; Minh
• Application Number:
  US10/945,464
• Publication Number:
  US 20050081031A1
• Time in Patent Office: 2,346 Days
• Field of Search: None
• US Class Current: 713/165
• CPC Class Codes: G06F 16/1744 using compression, e.g. sparse files
• CPC Class Codes: G06F 21/6209 to a single file or object, e.g. in a secure envelope, encrypted and accessed using a key, or with access control rules appended to the object itself
• CPC Class Codes: G06F 21/6218 to a system of files or objects, e.g. local or distributed file system or database
• CPC Class Codes: G06F 2221/2107 File encryption
• CPC Class Codes: G06F 2221/2153 Using hardware token as a secondary aspect
• CPC Class Codes: H04L 2209/30 Compression, e.g. Merkle-Damgard construction
• CPC Class Codes: H04L 9/0819 Key transport or distribution, i.e. key establishment techniques where one party creates or otherwise obtains a secret value, and securely transfers it to the other(s) network architectures or network communication protocols for key distribution in a packet data network H04L63/062
• CPC Class Codes: H04L 9/088 Usage controlling of secret information, e.g. techniques for restricting cryptographic keys to pre-authorized uses, different access levels, validity of crypto-period, different key- or password length, or different strong and weak cryptographic algorithms network architectures or network communication protocols for using time-dependent keys in a packet data network H04L63/068

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.

Claims

1. A method of placing data in a .Zip file format data container, said method including:

receiving a data file;

generating a first symmetric key based on first random data;

encrypting said data file to form an encrypted data file, wherein said encrypting includes symmetrically encrypting said data file using said first symmetric key;

generating a second symmetric key based on a second random data;

encrypting said first random data using said second symmetric key to form an encrypted random data;

asymmetrically encrypting said second symmetric key using a first asymmetric key to form first asymmetric key data;

asymmetrically encrypting said second symmetric key using a second asymmetric key to form second asymmetric key data; and

placing said encrypted data file, said encrypted random data, said first asymmetric key data and said second asymmetric key data in a data container, wherein said data container is constructed in accordance with a .Zip file format.

2. A .Zip file format data container recorded on a computer storage medium, said data container including:

an encrypted data file, wherein said encrypted data file has been symmetrically encrypted using a first symmetric key generated based on first random data;

encrypted random data formed by symmetrically encrypting said first random data using a second symmetric key generated based on a second random data;

a first set of encrypted data, wherein said first set of encrypted data is formed by asymmetrically encrypting said second symmetric key using a first asymmetric key; and

a second set of encrypted data, wherein said second set of encrypted data is formed by asymmetrically encrypting said second symmetric key using a second asymmetric key,

wherein said data container is constructed in accordance with a .Zip file format.