Sha1sum
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Template:Mono is a computer program that calculates and verifies SHA-1 hashes. It is commonly used to verify the integrity of files. It (or a variant) is installed by default on most Linux distributions. Typically distributed alongside sha1sum are Template:Mono, Template:Mono, Template:Mono and Template:Mono, which use a specific SHA-2 hash function and Template:Mono,[1] which uses the BLAKE2 cryptographic hash function.
The SHA-1 variants are proven vulnerable to collision attacks, and users should instead use, for example, a SHA-2 variant such as Template:Mono or the BLAKE2 variant Template:Mono to prevent tampering by an adversary.[2][3]
It is included in GNU Core Utilities,[4] Busybox (excluding Template:Mono),[5] and Toybox (excluding Template:Mono).[6] Ports to a wide variety of systems are available, including Microsoft Windows.
Examples
To create a file with a SHA-1 hash in it, if one is not provided:
$ sha1sum filename [filename2] ... > SHA1SUM
If distributing one file, the Template:Mono file extension may be appended to the filename e.g.:
$ sha1sum --binary my-zip.tar.gz > my-zip.tar.gz.sha1
The output contains one line per file of the form "{hash} SPACE (ASTERISK|SPACE) [{directory} SLASH] {filename}". (Note well, if the hash digest creation is performed in text mode instead of binary mode, then there will be two space characters instead of a single space character and an asterisk.) For example:
$ sha1sum -b my-zip.tar.gz
d5db29cd03a2ed055086cef9c31c252b4587d6d0 *my-zip.tar.gz
$ sha1sum -b subdir/filename2
55086cef9c87d6d031cd5db29cd03a2ed0252b45 *subdir/filename2
To verify that a file was downloaded correctly or that it has not been tampered with:
$ sha1sum -c SHA1SUM
filename: OK
filename2: OK
$ sha1sum -c my-zip.tar.gz.sha1
my-zip.tar.gz: OK
Hash file trees
Template:Mono can only create checksums of one or multiple files inside a directory, but not of a directory tree, i.e. of subdirectories, sub-subdirectories, etc. and the files they contain. This is possible by using Template:Mono in combination with the find command with the -exec option, or by piping the output from Template:Mono into xargs. Template:Mono can create checksums of a directory tree.
To use Template:Mono with Template:Mono:
$ find s_* -type f -exec sha1sum '{}' \;
65c23f142ff6bcfdddeccebc0e5e63c41c9c1721 s_1/file_s11
d3d59905cf5fc930cd4bf5b709d5ffdbaa9443b2 s_2/file_s21
5590e00ea904568199b86aee4b770fb1b5645ab8 s_a/file_02
Likewise, piping the output from Template:Mono into Template:Mono yields the same output:
$ find s_* -type f | xargs sha1sum
65c23f142ff6bcfdddeccebc0e5e63c41c9c1721 s_1/file_s11
d3d59905cf5fc930cd4bf5b709d5ffdbaa9443b2 s_2/file_s21
5590e00ea904568199b86aee4b770fb1b5645ab8 s_a/file_02
Related programs
- Template:Mono is a Perl program to calculate any of SHA-1, 224, 256, 384, 512 hashes.[7] It is part of the ActivePerl distribution.
- Template:Mono is a similarly named program that calculates SHA-3, HAKE, RawSHAKE, and Keccak functions.[8]
- The Template:Mono naming convention is also used by the BLAKE team with
b2sumandb3sum, by the programtthsum, and many others. - On FreeBSD and OpenBSD, the utilities are called Template:Mono, Template:Mono, Template:Mono, and Template:Mono. These versions offer slightly different options and features. Additionally, FreeBSD offers the Skein family of message digests.[9]
See also
References
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- ↑ – Template:Man/ManKier
- ↑ – Template:Man/ManKier
- ↑ – FreeBSD General Commands Manual
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