System and method for secure storage, transfer and retrieval of content addressable information

Abstract

An algorithm (such as the MD5 hash function) is applied to a file to produce an intrinsic unique identifier (IUI) for the file (or message digest). The file is encrypted using its IUI as the key for the encryption algorithm. An algorithm is then applied to the encrypted file to produce an IUI for the encrypted file. The encrypted file is safely stored or transferred within a network and is uniquely identifiable by its IUI. The encrypted file is decrypted using the IUI of the plaintext file as the key. The IUI serves as both a key to decrypt the file and also as verification that the integrity of the plaintext file has not been compromised. IUIs for any number of such encrypted files may be assembled into a descriptor file that includes meta data for each file, the IUI of the plaintext file and the IUI of the encrypted file. An algorithm is applied to the descriptor file to produce an IUI for the descriptor file. The plaintext descriptor file is then encrypted using the descriptor file IUI as a key for the encryption algorithm. An algorithm is applied to the encrypted descriptor file to produce an IUI for the encrypted descriptor file. The IUI of the encrypted descriptor file is a location-independent identifier to locate the encrypted descriptor file. A flattened descriptor file includes the IUIs of encrypted data files and the IUI of the encrypted descriptor file. An algorithm is applied to the flattened descriptor file to produce its own IUI.

Description

[0001] This application is related to U.S. patent application Ser. Nos. 091236,366 and 09 / 235,146 filed Jan. 21, 1999, which are hereby incorporated by reference. FIELD OF THE INVENTION [0002] The present invention relates generally to the secure storage, transfer and retrieval of information using a computer. More specifically, the present invention relates to a technique for identifying information using an intrinsic unique identifier and for securely storing, transferring and retrieving that information using related techniques. BACKGROUND OF THE INVENTION [0003] Digital information (such as a computer file) must often be identified to be in a particular state, denoted by the status of the information as of some event or time. Digital information is highly subject to change; normal attempts to improve the content, inadvertent commands or actions which change the content, or tampering by others are difficult to detect. [0004] Another problematic attribute of digital information is...

AI Technical Summary

Benefits of technology

[0015] In a first embodiment of the invention, an algorithm is applied to a file to produce an intrinsic unique identifier (IUI) for the file. To provide security for the file, the file is then encrypted using the recently produced IUI as a key for the encryption algorithm. The file may also be compressed in addition to being encrypted. An algorithm is then applied to the encrypted file to produce an IUI for the encrypted file. Thus, the encrypted file may be safely stored or transferred within a network and is uniquely identifiable by its IUI. An authorized party who obtains the encrypted file may then decrypt the encrypted file using the IUI of the plaintext file if he or she has access to this key. Using the IUI of the file to also serve as a key to encrypt the file provides many advantages. For example, a single identifier (in this case the IUI) serves as both a key to decrypt the file and also as verification that the integrity of the plaintext file has not been compromised. Further advantages and specific applications of this technique are presented below. In one specific embodiment, the MD5 algorithm is used to generate the IUI for the plaintext file. The resulting MD5 (the result of the hash function) may then be used to verify that the plaintext file has not changed.

[0020] Through use of the present invention, each file to be stored or transferred need only be encrypted once using one key, and only the encrypted version of the file need be manipulated. There is no need to use different keys for different users. Further, should the same file exist in two different locations on a computer or within a network, use of the present invention produces an encrypted file for each that is the same automatically. Thus, only this single encrypted file need be stored and / or transferred. Such benefits accrue automatically due to the nature of the present invention. The encrypted form of each file can be stored or transmitted anywhere within a computer network without the need for firewalls, access control, virtual private networks, or secure session protocols. Further, by using the intrinsic unique identifier to serve as the encryption key for the file as well, this single identifier not only serves to authenticate the file but also to verify the integrity of the file.

Problems solved by technology

The party would not, however, be able to decrypt the encrypted descriptor file unless it is also provided with the IUI of the descriptor file which has been used as an encryption key.

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