Which one is lossless, 7z or zip?

7z and zip are both lossless compression. 7z is a mainstream and efficient compression format with a very high compression ratio; the ZIP file format is a file format for data compression and document storage. 7z has a higher compression ratio, followed by zip; the zip format is more common and has a wide range of technologies, and the windows operating system supports the zip format by default.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

7z and zip are both lossless compression.

7z compression format

#7z is a mainstream and efficient compression format, which has a very high compression ratio . In computer science, 7z is an archive format that can use a variety of compression algorithms for data compression. The format was originally implemented and adopted by 7-Zip, but the file format is public and the 7-Zip software itself is open source under the GNU Lesser General Public License (GNU LGPL). The latest version of the LZMA software development kit is V9.34. The MIME type of the 7z format is application/x-7z-compressed.

Usually the 7z format using 7-Zip can be 30-70% smaller than the compressed file using zip format. And the zip format created with 7-Zip is 2-10% smaller than most other compression software.

Main Features:

• Open source and modular component structure (allows the use of any compression, conversion or encryption algorithm)

• Highest compression ratio

• Powerful AES-256 encryption

• Changeable and configurable compression algorithm

• Support very large files (up to 16EB)

• Unicode file name support

• Support solid Compression, allows internal files to be compressed in a stream, so that similar content is effectively compressed

• Supports file header compression

• Support multi-threaded compression

7z format supports 256-bit key AES algorithm encryption. The key is obtained by SHA-256 hashing the password provided by the user (using a large number of iterations to make brute force decoding of the password more difficult)

ZIP compression format

ZIP file format is a file format for data compression and document storage, formerly known as Deflate, the inventor was Phil Katz, who announced it in January 1989 information in this format.

ZIP usually uses the suffix ".zip", and its MIME format is application/zip. Currently, the ZIP format is one of several mainstream compression formats, and its competitors include the RAR format and the open source 7z format.

In terms of performance, RAR and 7z formats have higher compression rates than ZIP formats, and 7-Zip is gradually used in more fields because it provides free compression tools. get applied.

Microsoft has built-in support for the zip format starting from the Windows ME operating system. Even if the user’s computer does not have decompression software installed, it can open and create compressed files in the zip format, OS X and popular Linux operating systems. Similar support is provided for the zip format. Therefore, if you spread and distribute files on the Internet, the zip format is often the most commonly used choice.

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