RAR - What's new in the latest version
Version 7.00 beta 4
1. Bugs fixed:
a) fixed a crash in "Exhaustive search" -mcx archiving mode.
Version 7.00 beta 3
1. Faster CRC32 checksum calculation improves extraction and archiving
performance for archives utilizing this type of checksum.
Speed improvement can be noticeable when extracting large files,
especially files saved in -m0 mode without compression.
2. "Archive comment:" string is displayed before the archive comment.
Version 7.00 beta 2
1. Note to software developers: FCI_RAR5_COMPAT and UNPACK_MAX_DICT
values have been added in UnRAR source code 7.0.3. If earlier version
of UnRAR 7 source code was integrated into application, it is necessary
to update it to support them.
2. Console RAR filters out character 27 from screen output. It is done
for security reasons, because this character can be used to declare
ANSI escape control sequences in terminal applications.
We are thankful to Siddharth Dushantha for bringing this issue
to our attention.
3. Bugs fixed:
a) '+' character from "Generate archive name by mask" string was
included into resulting archive name.
Version 7.00 beta 1
1. Compression dictionary sizes larger than 1 GB are supported
for RAR archive format. Depending on the amount of physically
available memory, dictionary up to 64 GB can be selected.
Not power of 2 dictionary sizes can be specified for dictionaries
exceeding 4 GB. So we are not limited to 4, 8, 16, 32, 64 series
and can use values like 5 GB or 22 GB.
Archives with dictionaries exceeding 4 GB can be unpacked only
by RAR 7.0 or newer.
Increasing the dictionary size can improve the compression ratio
for large files with distant repeated blocks, like virtual machine
disk images. It also can be efficient for sets of large similar files
in a solid archive, such as a collection of software ISO images
differing by version or localization.
2. By default RAR refuses to unpack archives with dictionary exceeding
4 GB. It is done to prevent the unexpected excessive memory allocation.
Use -md<size> or -mdx<size> to allow unpacking dictionaries up to
and including the specified size. Unlike -md<size>, -mdx<size>
is applied to extraction only and can be added to RAR environment
variable, not affecting archiving commands.
3. Alternate search algorithm, optimized to locate longer and more distant
repeated data blocks, can be used when creating RAR archives.
It helps to improve the compression ratio and sometimes speed
for redundant data like big text files.
It increases memory usage and might reduce the compression speed
for some types of data. It can be turned on or off with
with -mcl[+|-] switch. If -mcl is not present, RAR applies the long
range search depending on the compression method, dictionary size
and other parameters.
This algorithm is required for dictionaries exceeding 4 GB
and turning it off is ignored for such dictionaries.
4. Much slower and more exhaustive repeated data search and compression
algorithm can be enabled with -mcx switch. It might provide
the additional compression gain for some types of redundant data,
but at much lower compression speed.
Long range search is needed to implement this mode efficiently,
so the exhaustive search option activates it automatically.
Both long range and exhaustive search option do not affect
the compatibility of created archives. So if dictionary size
is in 128 KB - 4 GB range, archives created with these search options
can be unpacked by all RAR versions beginning from 5.0.
5. Maximum path length limit is increased from 2047 to 65535 characters.
6. Creating archives in RAR 4.x format isn't supported anymore.
Options and switches specific for this format are removed.
It doesn't affect RAR 4.x archives decompression, which is included
into RAR.
7. Switch -ol- prohibits archiving and extracting symbolic links.
8. Switches -sl<size>[u] and -sm<size>[u] recognize [k|K|m|M|g|G|t|T]
size units for kilobytes, thousands of bytes, megabytes, millions
of bytes, gigabytes, billions of bytes, terabytes, trillions of bytes.
If unit character is 'b', 'B' or not present, bytes are assumed.
Previously these switches accepted bytes only.
9. Switch -v<size>[unit] recognizes 't' and 'T' as terabytes and
trillions of bytes for volume size units.
10. Proper progress is displayed when compressing symbolic link targets.
Version 6.24
1. Bugs fixed:
a) extraction command dereferenced a null pointer and crashed
when processing a zero length archive name in the archive metadata
stored with -am switch.
We are thankful to Radoslaw Madej from Check Point software
for reporting this issue.
Version 6.23
1. Bugs fixed:
a) a security issue involving out of bounds write is fixed
in RAR4 recovery volumes processing code.
We are thankful to goodbyeselene working with Trend Micro Zero Day
Initiative for letting us know about this bug.
Version 6.22
1. Bugs fixed:
a) extracting individual files from solid archives created by
RAR versions older than 2.0, could fail in RAR 6.20 and 6.21.
It didn't affect extracting the entire archive, which was performed
correctly.
Version 6.21
1. Bugs fixed:
a) if unencrypted file was stored after encrypted in the same
RAR archive and both files had been unpacked in the same extraction
command, RAR 6.20 failed to unpack the unencrypted file.
Version 6.20
1. Fixed the security vulnerability allowing to create unpacked files
outside of destination directory and to copy files resided outside of
destination directory into the destination directory.
We are thankful to Simon Scannell from Google for reporting it.
2. If extraction command involves only a part of files in RAR archive,
the additional archive analysis is performed when starting extraction.
It helps to properly unpack file references even if reference source
is not selected. It works for most of RAR archives except for volumes
on multiple removable media and archives containing a very large
number of references.
Also in some cases such analysis may help to optimize the amount
of processing data when extracting individual files from
semi-solid archives created with -s<N> and -se switches.
3. Switch -ams or just -am together with archive modification commands
can be used to save the archive name and creation time.
These saved parameters are displayed in header of "l" and "v" commands
output and can be restored with -amr switch combined with "ch" command,
such as "rar ch -amr arc.rar". If -amr is specified, "ch" ignores
other archive modification switches.
Restoring involves renaming an archive to original name and setting
the saved time as the archive modification time.
4. Faster RAR5 compression of poorly compressible data on modern CPUs
with 8 or more execution threads. This applies to all methods
except "Fastest", which performance remains the same.
5. "Repair" command efficiency is improved for shuffled data blocks
in recovery record protected RAR5 archives.
6. If file size has grown after archiving when creating non-solid
RAR volumes, such file is stored without compression regardless of
volume number, provided that file isn't split between volumes.
Previously it worked only for files in the first volume.
7. When archiving from stdin with -si switch, RAR displays the current
amount of read bytes as the progress indicator.
8. If wrong password is specified when adding files to encrypted
solid RAR5 archive, a password will be requested again.
Previous versions cancelled archiving in this case.
Version 6.12
1. Security vulnerability allowing to create unpacked files outside
of destination directory is fixed. This issue exists in Unix RAR only
and doesn't affect WinRAR and Android RAR.
We are thankful to Simon Scannell from SonarSource for reporting it.
Version 6.11
1. Switch -mes can be also used to suppress the password prompt
and abort when adding files to encrypted solid archive.
2. Additional measures to prevent extracting insecure links are
implemented.
Version 6.10
1. Switch -si can be used when extracting or testing to read archive
data from stdin, such as: cat docs.rar | rar x -si -o+ -pmypwd dummy docs/
Even though the archive name is ignored with this switch,
an arbitrary dummy archive name has to specified in the command line.
Operations requiring backward seeks are unavailable in this mode.
It includes displaying archive comments, testing the recovery record,
utilizing the quick open information, processing multivolume archives.
Prompts requiring user interaction are not allowed.
Use -o[+|-|r], -p<pwd> or -mes switches to suppress such prompts.
2. New -ep4<path> switch excludes the path prefix when archiving
or extracting if this path is found in the beginning of archived name.
Path is compared with names already prepared to store in archive,
without drive letters and leading path separators. For example:
rar a -ep4texts/books archive /texts/books/technical
removes "text/books" from archived names, so they start
from 'technical'.
3. New -mes switch skips encrypted files when extracting or testing.
It replaces former -p- switch.
4. New -op<path> switch sets the destination directory for 'x' and 'e'
extraction commands. Unlike <path_to_extract/> command line parameter,
this switch also accepts paths without trailing path separator
character.
5. If 'p' command is used to print a file to stdout, informational
messages are suppressed automatically to prevent them mixing
with file data.
6. "Generate archive name by mask" option and switch -ag treat only
first two 'M' characters after 'H' as minutes. Previously any
amount of such characters was considered as minutes.
It makes possible to place the time field before the date,
like -agHHMM-DDMMYY. Previous versions considered all 'M'
in this string as minutes.
7. Maximum allowed size of RAR5 recovery record is increased to 1000%
of protected data size. Maximum number of RAR5 recovery volumes
can be 10 times larger than protected RAR volumes.
Previous WinRAR versions are not able to use the recovery record
to repair broken archives if recovery record size exceeds 99%.
Similarly, previous versions cannot use recovery volumes
if their number is equal or larger than number of RAR volumes.
8. Warning is issued if entered password exceeds the allowed limit
of 127 characters and is truncated. Previously such passwords
had been truncated silently.
9. Command line -en switch is not supported anymore.
It created RAR4 archives without the end of archive record.
End of archive record permits to gracefully skip external data
like digital signatures.
10. Bugs fixed:
1) the total progress could be displayed incorrectly when using
-oi, -f, -u switches or appropriate GUI options.
Version 6.02
1. Switch -idn hides archived names also in 'v' and 'l' commands.
It can be useful if only the archive type or total information
is needed.
2. Bugs fixed:
a) after archiving data including a lot of directories,
Unix RAR could display less than 100% total progress percent,
even though it added all specified files and directories to archive.
Version 6.01
1. If -idn switch is used together with -t or -df in console RAR
when archiving, it additionally disables "Deleting <filename>"
or "Testing <filename>" messages, normally issued by these switches.
Also -idn disables directory creation messages when extracting
a file to non-existing directory.
Version 6.00
1. "Ignore" and "Ignore All" options are added to read error prompt.
"Ignore" allows to continue processing with already read file part
only and "Ignore All" does it for all future read errors.
For example, if you archive a file, which portion is locked by another
process, and if "Ignore" is selected in read error prompt,
only a part of file preceding the unreadable region will be saved
into archive.
It can help to avoid interrupting lengthy archiving operations,
though be aware that files archived with "Ignore" are incomplete.
If switch -y is specified, "Ignore" is applied to all files by default.
Previosuly available "Retry" and "Quit" options are still present
in read error prompt as well.
2. Exit code 12 is returned in case of read errors. This code is returned
for all options in the read error prompt, including a newly introduced
"Ignore" option.
Previously more common fatal error code 2 was returned for read errors.
3. New -ad2 switch places extracted files directly to archive's own folder.
Unlike -ad1, it does not create a separate subfolder for each unpacked
archive.
4. When unpacking a part of files from solid volume set, RAR attempts to
skip volumes in the beginning and start extraction from volume closest
to specified file and with reset solid statistics.
By default RAR resets the solid statistics in the beginning
of large enough solid volumes where possible. For such volumes
extracting a part of files from the middle of volume set can be
faster now.
It does not affect performance when all archived files are unpacked.
5. Previously RAR automatically resorted to extracting from first volume,
when user started extraction from non-first volume and first volume
was available. Now RAR does so only if all volumes between first
and specified are also available.
6. Switch -idn hides archived names output in archiving, extraction
and some other commands. Other messages and total percentage
are not affected.
You can use this switch to reduce visual clutter and console output
overhead when archiving or extracting a lot of small files.
Minor visual artifacts, such as percentage indicator overwriting
few last characters of error messages, are possible with -idn.
7. Switch -mci is removed. Optimized compression of Itanium executables
is not supported anymore. RAR still can decompress already existing
archives utilizing Itanium executable compression.
Version 5.91
1. Bugs fixed:
a) Unix RAR failed to properly unpack files from subfolders of
archives created by RAR 1.40.
Version 5.90
1. RAR compression speed is improved for CPUs with 16 and more cores.
2. "Fastest" method (-m1 command line equivalent) typically achieves
a higher compression ratio for highly compressible data types
when creating RAR5 archives.
3. Maximum number of utilized threads is increased from 32 to 64.
Command line -mt<threads> switch accepts values from 1 to 64.
4. "Repair" performance for RAR5 archives with recovery record
and without data shifts is improved. It deteriorated in RAR 5.80
and is now restored to original level.
5. Password prompt is not issued when performing recovery record based
repair for RAR5 archives with encrypted file names.
This command can be performed without providing a password.
6. Bugs fixed:
a) "Repair" command could erroneously display "Recovery record is
corrupt" message when processing an archive with valid recovery
record. This message did not prevent further repair operation.
Version 5.80
1. It is allowed to combine several modifiers in the same -ts switch.
For example, we can use -tsca instead -tsc -tsa.
2. Command line -agf<default_format> switch specifies the default format
string for -ag switch. It has a practical value only if placed to
rar.ini configuration file or to RAR environment variable.
For example, if we set RAR environment variable to -agfYYYY-MMM-DD,
we can use -ag without a parameter with YYYY-MMM-DD format string
assumed.
3. Switches -ed and -e+d can be used in archive processing commands
for any combination of RAR and archive operating systems.
In older versions RAR for Windows could not use them for Unix RAR
archives also as RAR for Unix for Windows RAR archives.
4. Similarly to RAR5 volumes, recovery volumes in RAR4 format use
the same width of volume number field as corresponding RAR volumes.
While previously RAR could create arc.part01.rar and arc.part1.rev
in RAR4 format, now both types of volumes will use "part01".
5. "Find string in archives" "i" command:
a) if "t" modifer is used, additionally to already supported
ANSI, OEM and UTF-16 encodings RAR will search the specified string
in UTF-8 files as well;
b) better performance, especially for case insensitive search;
c) hexadecimal search output includes both text and hexadecimal
representation of found matches.
6. Bugs fixed:
a) previous RAR version failed to unpack folder records
in archives created by RAR 1.50.
Version 5.71
1. Ctrl+C allows to abort RAR "l" command quickly. In previous versions
it could take several seconds until list command stopped.
2. Bugs fixed:
a) in "RAR x -x<mask> arcname" command, parent directories of files
matching the specified mask also were excluded from extracting.
Version 5.70
1. Command line -ta, -tb, -tn, -to switches accept 'm', 'c' and 'a'
modifiers after the switch name. So file time conditions can include
not only the file modification time as in previous versions,
but also creation (ctime "change time" for Unix) and last access time.
Such switch can include multiple modifiers to set the same date
for all specified times. For example, -tamc20190215 will process files
modified and created after 2019-02-15. New 'o' modifier permits to switch from AND to OR logic,
so -tamco20190215 includes files modified or created after 2019-02-15.
It is also allowed to specify several time filtering switches
with different dates in the same command line, like:
-taco20190201 -tbmo20190210
Switches -ta and -tn also include files matching the specified date
exactly. Switches -tb and -to exclude such files.
2. New -ad1 switch can be used when unpacking multiple archives
recursively, such as 'rar x -r -ad1 arc\*.rar'. It creates
a separate folder for files unpacked from each archive,
but unlike already existing -ad switch, it creates such folders
in each archive folder.
3. Bugs fixed:
a) RAR mixed up source and destination file sizes and times
in the overwrite prompt when updating a file in RAR archive
with -o switch;
b) commands modifying an existing RAR4 volume reset the volume number
field to 1. While it did not affect extraction, tools like WinRAR
displayed a wrong volume number for such volumes;
c) fixed a crash when reading an archive comment from a corrupt
RAR file.
Version 5.61
1. Fixed a crash when processing corrupt RAR archives.
This issue may be also associated with security risks.
Version 5.60
1. "Repair" command efficiency is improved for recovery record protected
RAR5 archives. Now it can detect deletions and insertions of unlimited
size also as shuffled data including data taken from several recovery
record protected archives and merged into a single file in arbitrary
order.
2. If encoding of comment file specified in -z<file> switch is not
defined with -sc switch, RAR attempts to detect UTF-8, UTF-16LE
and UTF-16BE encodings based on the byte order mask and data
validity tests.
3. "Update" and "Fresh" commands ('u' and 'f' in the command line mode)
quit immediately if no files are to be updated. Previously they created
a temporary archive before quitting when updating archives with recovery
record or quick open information.
4. "Repair" command issues "Recovery record is corrupt" message
after repairing RAR5 archive containing a broken recovery record.
Previously such message was issued only by "Test" command
and "Repair" handled most of recovery record damages silently.
5. Bugs fixed:
a) fixed potential security issues when processing corrupt
RAR archives;
b) -tl and -tk switches did not work with archive modification
commands;
c) command like 'rar a arcname.rar subdir/arcname.rar' erroneously
issued "No files" warning and refused to add the file.
Version 5.50
1. RAR uses RAR 5.0 archive format by default. You can change it to
RAR 4.x compatible format with -ma4 command line switch.
2. Added support for 1 nanosecond file time precision on Unix platform.
3. You can specify 'f' charset value in -sc switch to use UTF-8
encoding. For example:
rar a -scfl arcname @filelist.txt
to read contents of filelist.txt as UTF-8 text.
4. RAR "lt" and "vt" commands display file times with nanosecond
precision. Such precision is used in RAR5 archives created
by RAR/Unix 5.50. Archives created by Windows RAR version
have 100ns file time precision.
5. Only '+', '-' and '1' precision modifiers are supported
in -ts switch now. Use '+' to store the file time with maximum
precision, '-' to omit the file time and '1' to store it with
1 second precision. Intermediate precision modes previously
defined with '2' and '3' modifiers are not available in RAR 5.0
archive format and ignored by -ts switch.
6. If a wrong password is entered when unpacking an encrypted file
in RAR5 archive, RAR proposes to enter a valid password
for same file again instead of aborting extraction.
7. Bugs fixed:
a) fixed crashes and security vulnerability when unpacking corrupt
RAR archives;
b) directory owners were not set when extracting RAR5 archives
created with -ow switch;
c) if only creation or only last access file time was stored in RAR5
archive with 1 second precision, such as with -ma5 -tsm- -tsa1
switches, this stored time was ignored when extracting.
Version 5.40
1. If RAR recovery volumes (.rev files) are present in the same directory
as usual RAR volumes, archive test command verifies .rev contents
after completing testing .rar files.
If you wish to test only .rev files without checking .rar volumes,
you can run:
rar t arcname.part1.rev
2. Previously "Synchronize archive contents" mode (-as switch) aborted
if some of archiving directories could not be read. Now RAR continues
performing the operation and preserves archived files matching
unreadable directories.
3. If -iver switch is specified, RAR displays the version number
and quits. You can run just "RAR -iver".
4. If -p switch is used without optional <pwd> parameter,
a password can be also set with file redirection or pipe.
For example: rar -p myarc.rar myfiles < psw.txt
5. RAR treats 'arcname.partN' as 'arcname.partN.rar'
if 'arcname.partN' does not exist and 'arcname.part#.rar' exists.
For example, it is allowed to run:
RAR x arcname.part01
to start extraction from arcname.part01.rar
6. Maximum comment length for RAR archives is increased
from 64 to 256 KB.
7. Switch -scul can be used to process big endian UTF-16 list files
as well, provided that they have a correct byte order mark.
Previously it allowed only little endian file lists.
Version 5.30
1. Directory wildcards are allowed in RAR command line in file names to
archive. For example:
rar a backup c:\backup\2015*\*
Recursion is enabled automatically for such directory wildcards
even if -r switch is not specified.
2. New 'R' object for -sc switch defines encoding of console
RAR messages sent to redirected files and pipes. For example:
rar lb -scur data > list.txt
will produce Unicode list.txt with archived file names.
3. Console RAR "l" and "v" commands display file time in YYYY-MM-DD
format.
4. "Test" command also verifies contents of NTFS alternate data streams
in RAR 3.x - 5.x archives. Previously their contents was checked
only during extraction command.
5. Bugs fixed:
a) console RAR crashed instead of displaying an overwrite prompt
when attempting to add files to already existing volumes;
b) console RAR "lt" command did not display seconds in file timestamp.
Version 5.21
1. While previous versions could produce RAR5 volumes of slightly
smaller than requested size sometimes, such situation is less
likely now. In most cases volume size equals to specified by user.
2. Now by default RAR skips symbolic links with absolute paths
in link target when extracting. You can enable creating such links
with -ola switch.
Such links pointing to directories outside of extraction destination
directory can present a security risk. Enable their extraction only
if you are sure that archive contents is safe, such as your own backup.
Version 5.20
1. RAR can read the default set of switches from .rarrc file stored
in the user's home directory. Previously it was possible to
define only the same set of switches for all RAR command with
"switches=<switches>" string. Now .rarrc also allows to specify
separate switch sets for individual RAR commands using
the following syntax:
switches_<command>=<any RAR switches, separated by spaces>
For example:
switches_a=-m5 -s
switches_x=-o+
2. File overwrite prompt displays the size and modification time
for existing and new files.
3. When archiving from stdin with -si switch, RAR sets the current system
time to modification time of archived file. Previous version did not
set this time at all.
4. It is possible to use -si and -v<size> switches together. Previous
versions did not allow to create volumes when archiving from stdin.
Version 5.11
1. Timestamp is set to extracted symlinks.
2. Bugs fixed:
a) deleting a file in RAR5 solid archive containing files stored
with -ver switch caused such files to lose version information.
Version 5.10
1. Switch -ai can be used when creating RAR archive,
so predefined values, typical for file and directory,
are stored instead of actual attributes.
Previously this switch could be used only when extracting.
Version 5.00
1. New RAR 5.0 archiving format. You can use -ma command line switch
to create RAR 5.0 archives. By default RAR creates archives
in 4.x format.
2. Changes in RAR 5.0 compression algorithm:
a) maximum compression dictionary size is increased up to 1 GB
in 64 bit RAR. 32 bit RAR version can use up to 256 MB
dictionary when creating an archive. Both 32 bit and 64 bit
versions can unpack archives with any dictionary size,
including 1 GB;
b) default dictionary size for RAR 5.0 is 32 MB, typically resulting
in higher compression ratio and lower speed than RAR 4.x 4 MB.
You can use -md<size> switch to change this value;
c) -md<size> switch syntax is modified to support larger dictionary
sizes. Append 'k', 'm' and 'g' modifiers to specify the size
in kilo-, mega- and gigabytes, like -md64m for 64 MB dictionary.
If modifiers are not present, megabytes are assumed,
so -md64m is equal to -md64;
d) RAR 5.0 format includes Intel IA-32 executable and delta
compression algorithms, but RAR 4.x text, audio, true color
and Itanium algorithms are not supported. These excluded algorithms
are not efficient for modern data types and hardware configurations;
e) RAR 5.0 decompression can utilize several CPU cores.
Though not to same extent as in compression algorithm,
it improves the decompression speed on large files
with poorly compressible data or when using BLAKE2 checksums.
3. Changes in RAR 5.0 archive format:
a) file times are stored as Coordinated Universal Time (UTC)
instead of former local time, making file exchange among
several time zones more straightforward;
b) file names and archive comments use UTF-8 encoding.
4. RAR 5.0 recovery record is based on Reed-Solomon error correction
codes. If recovery record size is large enough, 5% and more,
the new error correction scheme provides much higher resistance to
multiple damages comparing to RAR 4.x recovery record.
Smaller record, such as 1 - 2%, or less random damage type would
result in less difference between 4.x and 5.0. For single continuous
damage 4.x and 5.0 efficiency is about the same.
Additionally to usual data erasures, the new recovery record
is able to detect deletions and insertions of much larger size
than in previous RAR versions. Maximum insertion size is several
megabytes. Maximum deletion size depends on the damage type
and in some cases can be as large as the recovery record size.
Still, the best recovery performance and efficiency is achieved
if no deletions and insertions are present, so all data including
damaged sectors preserve their original positions. Thus, if you use
some special software to copy an archive from damaged media,
it is better to choose the mode, when damaged sectors are filled by
zeroes or any other data instead of cutting them out completely
from resulting file.
RAR 5.0 recovery record is more resistant to damage of recovery record
itself and can utilize a partially corrupt recovery record data.
Note, though, that "Repair" command does not fix broken blocks
in recovery record. Only file data are corrected. After successful
archive repair, you may need to create a new recovery record
for saved files.
New recovery record is not based on 512 byte sectors anymore and incorporates more complicated data structures. So it is impossible
to specify its size in sectors. For RAR 5.0 archives the parameter of
-rr[N] switch and rr[N] command is always treated as a percent of
archive size regardless of presence of % character. Typically N%
recovery record can repair up to N% of continuously damaged data
and increases the archive size by only slightly more than N%.
Ability to fix multiple damages is proportional to N.
We used "Screaming Fast Galois Field Arithmetic Using Intel
SIMD Instructions" paper by James S. Plank, Kevin M. Greenan
and Ethan L. Miller to improve Reed-Solomon coding performance.
Also we are grateful to Artem Drobanov and Bulat Ziganshin
for samples and ideas allowed to make Reed-Solomon coding
more efficient.
5. "Test" command verifies validity of RAR 5.0 recovery record.
Recovery record is tested after processing all archived files.
If corrupt archive contains the recovery record, it might be possible
to repair it even if recovery record validity test is failed.
"Repair" command attempts to utilize even a partially damaged
recovery record. So treat the negative recovery record test result
as a reason to re-create the archive if original files are still
available, but not as a reason to avoid "Repair" command.
6. Changes in RAR 5.0 encryption algorithm:
a) encryption algorithm is changed from AES-128 to AES-256 in CBC mode.
Key derivation function is based on PBKDF2 using HMAC-SHA256;
b) special password verification value allows to detect most of
wrong passwords without necessity to unpack the entire file;
c) if archive headers are not encrypted ("Encrypt file names" option
is off), file checksums for encrypted RAR 5.0 files are modified
using a special password dependent algorithm, to make impossible
guessing file contents based on checksums. Do not expect such
encrypted file checksums to match usual CRC32 and BLAKE2 values.
7. Switch -htb allows to utilize 256 bit length BLAKE2sp hash
( https://blake2.net ) instead of 32 bit CRC32 as a file checksum.
While producing slightly larger archives, BLAKE2 can be used
for file contents identification. If two files have the same
BLAKE2 value, it practically guarantees that file contents
is the same. BLAKE2 error detection property is also stronger
than in much shorter CRC32.
8. Features removed:
a) authenticity verification feature did not provide the required
level of reliability and was removed;
b) switch -en (do not add "end of archive" block) is not supported
by RAR 5.0 archives, which always have the end of archive block.
This block helps RAR to safely skip external data like
digital signatures appended to archive;
c) old style extension based arcname.rNN volume names are not
supported by RAR 5.0 archives, which use only arcname.partN.rar
volume names;
d) file comments are not supported anymore both in RAR 4.x
and RAR 5.0 archives. Console RAR 'cf' command is removed.
It does not affect the archive comment support, which is present
in both versions of archive format and is not planned for removal.
9. Switch -oh stores hard links as link instead of file. It is available
only for RAR 5.0 archive format.
10. Changes in recovery volume processing in RAR 5.0 archive format:
a) maximum number of RAR+REV volumes in RAR 5.0 format is 65535
instead of 255;
b) recovery volume operations are faster than in RAR 4.x;
c) additionally to recovery data, RAR 5.0 REV files also store
service information such as checksums of protected RAR files.
So they are slightly larger than RAR volumes which they protect.
If you plan to copy individual RAR and REV files to some removable
media, you need to take it into account and specify RAR volume
size by a few kilobytes smaller than media size.
11. Command line RAR returns the exit code 11 if it can detect that
user entered a wrong password. This code can be returned only
for RAR 5.0 archives. It is impossible to distinguish a wrong
password and data damage for RAR 4.x archives.
12. 'v' and 'l' commands display archived file names in the end of line,
not in that beginning as before. Also some fields previously
available in 'l' and 'v' output are now shown only by 'lt' and 'vt'.
'vt' and 'lt' commands provide the detailed multiline information
for every archived file.
'vta' and 'lta' also include service headers into list.
13. UTF-16 little endian encoding is used in RAR log file rar.log,
so Unicode file names are stored in the log correctly.
You can use -sc<charset>g switch to change the default log file
encoding, such as -scag for native single byte encoding.
14. Command line 'r' (repair) command can include an optional destpath\
parameter defining the destination folder for repaired archive:
rar r archive.rar destpath\