ZIP is one of the most widely used compressed file formats. It is universally used to aggregate, compress, and encrypt files into a single interoperable container. We have developed a methodology for recovery which has been embedded into an Intelli-Carve® recovery profile. Our software has the ability to read and validate ZIP archives directly from a stream.
In addition to being used as a compression file format, ZIP is also used in a number of proprietary file formats such as those used for the following file types:
- Microsoft Word from 2007
- Microsoft Powerpoint from 2007
- Microsoft Excel from 2007
- OpenOffice Documents
- StarOffice Documents
- Adobe AIR installation packages
ZIP files contain three main objects:
- End of Central Directory structure
- Central Directory comprising of one or more Central Directory File Header structures
- One or more Local File Header structures
Our Blade® Intelli-Carve® profile understands the structure of the ZIP Archive and can load the data directly from a stream. A verification process checks that the End of Central Directory structure contains valid data; if this verification process is successful, Blade® then reads the Central Directory File Headers. On completion, the Local File Header structures are read and verified. During this process, Blade® decompresses each stream to ensure there are no errors. Once the data has been verified, we identify the file type by examining the data contained in some of the compressed streams. The file is then written out with the appropriate file extension.