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Overview

7-Zip is free software distributed primarily under the GNU LGPL license, with specific exceptions for certain components. 7-Zip Copyright (C) 1999-2026 Igor Pavlov.

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License Summary by Component

The 7-Zip source code uses different licenses depending on the specific files:
ComponentLicenseNotes
Most source filesGNU LGPL v2.1+Default license for files without explicit license statements
RAR decompressionGNU LGPL + unRAR restrictionCPP/7zip/Compress/Rar* files
LZFSE decoderBSD 3-clauseCPP/7zip/Compress/LzfseDecoder.cpp
ZSTD decoderBSD 3-clauseC/ZstdDec.c
XXH64 hashBSD 2-clauseC/Xxh64.c
Public domain filesPublic domainWhen explicitly stated in source file
LZMA SDKPublic domainWritten by Igor Pavlov
If a source file contains no license information, it falls under the GNU LGPL license.

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GNU LGPL License

Most of the 7-Zip source code is licensed under the GNU Lesser General Public License (LGPL) version 2.1 or later.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, you can get a copy of 
the GNU Lesser General Public License from http://www.gnu.org/
Key Points:
  • Free to use, modify, and redistribute
  • No warranty provided
  • Must comply with LGPL terms for distribution
  • See DOC/copying.txt for full license text

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unRAR License Restriction

The RAR decompression code has additional restrictions beyond the GNU LGPL. You must comply with BOTH the GNU LGPL and the unRAR license restriction.

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Files Affected

All files matching the pattern CPP/7zip/Compress/Rar* are subject to the “GNU LGPL with unRAR license restriction.”

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unRAR License Terms

The decompression engine for RAR archives was developed using source code from the unRAR program.Copyright: All copyrights to original unRAR code are owned by Alexander Roshal.Key Restrictions:
  1. Cannot recreate RAR compression algorithm - The unRAR sources cannot be used to re-create the RAR compression algorithm, which is proprietary.
  2. Distribution requirements - Distribution of modified unRAR sources (in separate form or as part of other software) is permitted, provided that:
    • It is clearly stated in the documentation
    • It is clearly stated in source comments
    • The code may NOT be used to develop a RAR (WinRAR) compatible archiver
Permitted Uses:
The unRAR sources may be used in any software to handle RAR
archives without limitations free of charge, but cannot be used
to re-create the RAR compression algorithm, which is proprietary.
What You CAN Do:
  • Use compiled files under GNU LGPL rules (unRAR license has minimal restrictions on compiled files)
  • Link compiled files to LGPL programs
  • Fix bugs in source code and use the compiled fixed version
  • Decompress RAR archives
  • Handle RAR archives in your software
What You CANNOT Do:
  • Use unRAR sources to re-create the RAR compression algorithm
  • Develop a RAR (WinRAR) compatible archiver
  • Charge fees for distributing unRAR without written permission from Alexander Roshal

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Disclaimer

THE RAR ARCHIVER AND THE UNRAR UTILITY ARE DISTRIBUTED "AS IS".
NO WARRANTY OF ANY KIND IS EXPRESSED OR IMPLIED. YOU USE AT 
YOUR OWN RISK. THE AUTHOR WILL NOT BE LIABLE FOR DATA LOSS, 
DAMAGES, LOSS OF PROFITS OR ANY OTHER KIND OF LOSS WHILE USING
OR MISUSING THIS SOFTWARE.

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BSD 3-Clause License

The following components use the BSD 3-clause License:

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LZFSE Decompression

  • File: CPP/7zip/Compress/LzfseDecoder.cpp
  • Origin: Derived from LZFSE compression library by Apple Inc.
  • Copyright:
    • (c) 2015-2016, Apple Inc. All rights reserved.
    • (c) 2023-2026 Igor Pavlov.

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ZSTD Decompression

  • File: C/ZstdDec.c
  • Origin: Developed using original zstd decoder code as reference
  • Original Developer: Facebook Inc.
  • Copyright:
    • (c) Facebook, Inc. All rights reserved.
    • (c) 2023-2026 Igor Pavlov.

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License Text

Redistribution and use in source and binary forms, with or without 
modification, are permitted provided that the following conditions 
are met:

1. Redistributions of source code must retain the above copyright 
   notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright 
   notice, this list of conditions and the following disclaimer in 
   the documentation and/or other materials provided with the 
   distribution.

3. Neither the name of the copyright holder nor the names of its 
   contributors may be used to endorse or promote products derived 
   from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 
FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 
COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 
BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
POSSIBILITY OF SUCH DAMAGE.

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BSD 2-Clause License

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XXH64 Hash Function

  • File: C/Xxh64.c
  • Origin: Derived from original XXH64 code by Yann Collet
  • Copyright:
    • (c) 2012-2021 Yann Collet.
    • (c) 2023-2026 Igor Pavlov.

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License Text

Redistribution and use in source and binary forms, with or without 
modification, are permitted provided that the following conditions 
are met:

1. Redistributions of source code must retain the above copyright 
   notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright 
   notice, this list of conditions and the following disclaimer in 
   the documentation and/or other materials provided with the 
   distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 
FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 
COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 
BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
POSSIBILITY OF SUCH DAMAGE.

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Public Domain Components

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LZMA SDK

The LZMA SDK is written and placed in the public domain by Igor Pavlov.

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Other Public Domain Files

Some files in the 7-Zip source are explicitly marked as public domain in their source code headers.

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Compilation Options for License Compliance

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Excluding RAR Code

If the unRAR license restrictions are not compatible with your project’s requirements, you can exclude RAR-related code during compilation:
Option 1: DISABLE_RAR_COMPRESS=1Removes “not fully free” RAR decompression codecs from compilation.
make -f makefile.gcc DISABLE_RAR_COMPRESS=1
Capabilities with this option:
  • Open RAR archives
  • List files in RAR archives
  • Extract files that are stored without compression
Limitations:
  • Cannot decompress compressed files from RAR archives
Option 2: DISABLE_RAR=1Completely removes all RAR-related code from compilation.
make -f makefile.gcc DISABLE_RAR=1
Limitations:
  • No RAR archive support at all

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License Compatibility Summary

When distributing 7-Zip or incorporating it into your project, ensure you comply with ALL applicable licenses:
  • GNU LGPL for most code
  • GNU LGPL + unRAR restriction for RAR decompression
  • BSD 3-clause for LZFSE and ZSTD decoders
  • BSD 2-clause for XXH64 hash
  • Public domain for LZMA SDK
The unRAR restriction is the most restrictive component and may not be compatible with some free-software licenses.

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Additional Resources

  • License.txt - Complete license documentation
  • copying.txt - Full GNU LGPL license text
  • unRarLicense.txt - Complete unRAR license
  • GNU LGPL: http://www.gnu.org/

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Contact

For licensing questions or permissions: Igor Pavlov
http://www.7-zip.org

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