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 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:
- LZMA - Improved and optimized version of LZ77 algorithm
- LZMA2 - Improved version of LZMA
- PPMD - Dmitry Shkarin's PPMdH with small changes
- BCJ - Converter for 32-bit x86 executables
- BCJ2 - Converter for 32-bit x86 executables
- BZip2 - Standard BWT algorithm
- 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.