7Zip Download

complete features :

• Highest compression ratio in new 7z format with LZMA compression
• 7-Zip is free software distributed under the GNU LGPL
• Supported formats: 7z, ZIP, CAB, RAR, ARJ, GZIP, BZIP2, TAR, CPIO, RPM and DEB
• For ZIP and GZIP formats 7-Zip provides compression ratio that is 2-10 % better than ratio provided by PKZip and WinZip
• Self-extracting capability for 7z format
• Integration with Windows Shell
• Powerful File Manager
• Powerful command line version
• Plugin for FAR Manager
• Localizations for 47 languages
• works in DOS using HX Extender
• There is port of command line version for DOS, Linux/Unix.
• High compression ratio in new 7z format with LZMA compression.

7z Format

7z is the new archive format, providing high compression ratio.

The main features of 7z format:

• Open architecture
• High compression ratio
• Strong AES-256 encryption
• Ability of using any compression, conversion or encryption method
• Supporting files with sizes up to 16000000000 GB
• Unicode file names
• Solid compressing
• Archive headers compressing

7z has open architecture, so it can support any new compression methods. Now the following methods are integrated to 7z:

1. LZMA - Improved and optimized version of LZ77 algorithm
2. LZMA2 - Improved version of LZMA
3. PPMD - Dmitry Shkarin's PPMdH with small changes
4. BCJ - Converter for 32-bit x86 executables
5. BCJ2 - Converter for 32-bit x86 executables
6. BZip2 - Standard BWT algorithm
7. Deflate - Standard LZ77-based algorithm

LZMA is default and general compression method of 7z format.

The main features of LZMA method:

• High compression ratio
• Variable dictionary size (up to 4 GB)
• Compressing speed: about 1 MB/s on 2 GHz CPU
• Decompressing speed: about 10-20 MB/s on 2 GHz CPU
• Small memory requirements for decompressing (depend from dictionary size)
• Small code size for decompressing: about 5 KB
• Supporting multi-threading and P4's hyper-threading

LZMA compression algorithm is very suitable for embedded applications.

7-Zip also supports encryption with AES-256 algorithm. This algorithm uses cipher key with length of 256 bits. To create that key 7-Zip uses derivation function based on SHA-256 hash algorithm. A key derivation function produces a derived key from text password defined by user. For increasing the cost of exhaustive search for passwords 7-Zip uses big number of iterations to produce cipher key from text password.

7z is a part of 7-Zip program distributed under the GNU LGPL. LZMA is released under the terms of the GNU LGPL.

Applications that support 7z archives: WinRAR, PowerArchiver, TUGZip, IZArc.