Method and apparatus for protecting widely distributed digital information

A method of encrypting and storing an original, unitary file of data comprising:

• dividing the unitary file into a plurality of segments;
• allocating to each of said segments a corresponding portion of a single physical storage medium;
• storing a first of said segments in a corresponding portion of the single physical storage medium without encryption;
• encrypting a second of said segments;
• and
• storing the encrypted segment in a corresponding portion of the single physical storage medium;
• wherein at least one of the encrypted segments is encrypted with a different encryption procedure than another of the encrypted segments.

A computer-readable storage medium having stored therein instructions capable of causing a computer to perform the following method:

• receiving a request through a computer operating system to read a unitary file of data, said file comprising a plurality of non-encrypted segments interspersed with at least two encrypted segments on a single storage medium;
• determining which of said file segments is encrypted;
• reading the encrypted segment and decrypting same;
• reading the non-encrypted segments;
• assembling the non-encrypted segments with the decrypted segment to produce an original unitary file of data;
• and
• providing the assembled file of data in response to said request;
• wherein some of the encrypted segments are encrypted with different encryption procedures than others of the encrypted segments.

A computer-readable storage medium having stored therein instructions capable of causing a computer to perform the following method:

• dividing a unitary file into a plurality of segments;
• allocating to each of said segments a corresponding portion of a single physical storage medium;
• storing a first of said segments in a corresponding portion of the single physical storage medium without encryption;
• encrypting a second of said segments using a first encryption technique;
• encrypting a third of said segments using a second encryption technique;
• and
• storing the encrypted segment in a corresponding portion of the single physical storage medium.

A method of file system operation in a computer comprising:

• receiving a request through a computer operating system to read a unitary file of data, said unitary file comprising a plurality of non-encrypted segments interspersed with at least one encrypted segments;
• determining which of said file segments is encrypted;
• reading the encrypted segment and decrypting same;
• reading the non-encrypted segments;
• assembling the non-encrypted segments with the decrypted segment to produce an original unitary file of data;
• and
• providing the assembled unitary file of data in response to said request;
• wherein the unitary file of data cannot be used without a decryption key.

A computer system including a microprocessor and a software program, the software program utilizing an application program interface to request services from a windowed operating system, the requested services relating to transparent sector-based encryption and decryption of information stored on a single storage medium in a file system of a computer operating system, wherein file data is protected from unauthorized use, yet is transparently available to a user without delay associated with decrypting, the application program interface including a separate command to request each of the following services:

• identifying one or more keys useful for decrypting a unitary file written as a plurality of non-encrypted segments interspersed with at least one encrypted segments;
• and
• reading a unitary file of data, said file comprising a plurality of non-encrypted segments interspersed with the at least one encrypted segments using one or more decryption procedures;
• wherein the unitary file is not usable when it contains the at least one encrypted segments, without a decryption key.