2768d70567
While there, remove .Tn from man pages. Also remove an obsolete comment about the 80386. MFC after: 1 week Sponsored by: Klara, Inc. Reviewed by: kevans, allanjude Differential Revision: https://reviews.freebsd.org/D38373
265 lines
7.4 KiB
Groff
265 lines
7.4 KiB
Groff
.\" $FreeBSD$
|
|
.Dd February 6, 2023
|
|
.Dt MD5 1
|
|
.Os
|
|
.Sh NAME
|
|
.Nm md5 , sha1 , sha224 , sha256 , sha384 ,
|
|
.Nm sha512 , sha512t224 , sha512t256 ,
|
|
.Nm rmd160 , skein256 , skein512 , skein1024 ,
|
|
.Nm md5sum , sha1sum , sha224sum , sha256sum , sha384sum ,
|
|
.Nm sha512sum , sha512t224sum , sha512t256sum ,
|
|
.Nm rmd160sum , skein256sum , skein512sum , skein1024sum
|
|
.Nd calculate a message-digest fingerprint (checksum) for a file
|
|
.Sh SYNOPSIS
|
|
.Nm
|
|
.Op Fl pqrtx
|
|
.Op Fl c Ar string
|
|
.Op Fl s Ar string
|
|
.Op Ar
|
|
.Pp
|
|
.Nm md5sum
|
|
.Op Fl pqrtx
|
|
.Op Fl c Ar file
|
|
.Op Fl s Ar string
|
|
.Op Ar
|
|
.Pp
|
|
(All other hashes have the same options and usage.)
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm md5 , sha1 , sha224 , sha256 , sha384 , sha512 , sha512t224 , sha512t256 ,
|
|
.Nm rmd160 , skein256 , skein512 ,
|
|
and
|
|
.Nm skein1024
|
|
utilities take as input a message of arbitrary length and produce as
|
|
output a
|
|
.Dq fingerprint
|
|
or
|
|
.Dq message digest
|
|
of the input.
|
|
The
|
|
.Nm md5sum , sha1sum , sha224sum , sha256sum , sha384sum , sha512sum ,
|
|
.Nm sha512t224sum , sha512t256sum , rmd160sum , skein256sum , skein512sum ,
|
|
and
|
|
.Nm skein1024sum
|
|
utilities do the same, but default to the reversed format of
|
|
the
|
|
.Fl r
|
|
flag.
|
|
It is conjectured that it is computationally infeasible to
|
|
produce two messages having the same message digest, or to produce any
|
|
message having a given prespecified target message digest.
|
|
The SHA-224 , SHA-256 , SHA-384 , SHA-512, RIPEMD-160,
|
|
and SKEIN
|
|
algorithms are intended for digital signature applications, where a
|
|
large file must be
|
|
.Dq compressed
|
|
in a secure manner before being encrypted with a private
|
|
(secret)
|
|
key under a public-key cryptosystem such as RSA.
|
|
.Pp
|
|
The MD5 and SHA-1 algorithms have been proven to be vulnerable to practical
|
|
collision attacks and should not be relied upon to produce unique outputs,
|
|
.Em nor should they be used as part of a cryptographic signature scheme.
|
|
As of 2017-03-02, there is no publicly known method to
|
|
.Em reverse
|
|
either algorithm, i.e., to find an input that produces a specific
|
|
output.
|
|
.Pp
|
|
SHA-512t256 is a version of SHA-512 truncated to only 256 bits.
|
|
On 64-bit hardware, this algorithm is approximately 50% faster than SHA-256 but
|
|
with the same level of security.
|
|
The hashes are not interchangeable.
|
|
.Pp
|
|
SHA-512t224 is identical to SHA-512t256, but with the digest truncated
|
|
to 224 bits.
|
|
.Pp
|
|
It is recommended that all new applications use SHA-512 or SKEIN-512
|
|
instead of one of the other hash functions.
|
|
.Pp
|
|
The following options may be used in any combination and must
|
|
precede any files named on the command line.
|
|
The hexadecimal checksum of each file listed on the command line is printed
|
|
after the options are processed.
|
|
.Bl -tag -width indent
|
|
.It Fl b
|
|
Make the
|
|
.Nm -sum
|
|
programs separate hash and digest with a blank followed by an asterisk instead
|
|
of by 2 blank characters for full compatibility with the output generated by the
|
|
coreutils versions of these programs.
|
|
.It Fl c Ar string
|
|
If the program was called with a name that does not end in
|
|
.Nm sum ,
|
|
compare the digest of the file against this string.
|
|
If combined with the
|
|
.Fl q
|
|
option, the calculated digest is printed in addition to the exit status being set.
|
|
.Pq Note that this option is not yet useful if multiple files are specified.
|
|
.It Fl c Ar file
|
|
If the program was called with a name that does end in
|
|
.Nm sum ,
|
|
the file passed as argument must contain digest lines generated by the same
|
|
digest algorithm with or without the
|
|
.Fl r
|
|
option
|
|
.Pq i.e., in either classical BSD format or in GNU coreutils format .
|
|
A line with the file name followed by a colon
|
|
.Dq ":"
|
|
and either OK or FAILED is written for each well-formed line in the digest file.
|
|
If applicable, the number of failed comparisons and the number of lines that were
|
|
skipped since they were not well-formed are printed at the end.
|
|
The
|
|
.Fl q
|
|
option can be used to quiesce the output unless there are mismatched entries in
|
|
the digest.
|
|
.Pp
|
|
.It Fl s Ar string
|
|
Print a checksum of the given
|
|
.Ar string .
|
|
.It Fl p
|
|
Echo stdin to stdout and append the checksum to stdout.
|
|
.It Fl q
|
|
Quiet mode \(em only the checksum is printed out.
|
|
Overrides the
|
|
.Fl r
|
|
option.
|
|
.It Fl r
|
|
Reverses the format of the output.
|
|
This helps with visual diffs.
|
|
Does nothing
|
|
when combined with the
|
|
.Fl ptx
|
|
options.
|
|
.It Fl t
|
|
Run a built-in time trial.
|
|
For the
|
|
.Nm -sum
|
|
versions, this is a nop for compatibility with coreutils.
|
|
.It Fl x
|
|
Run a built-in test script.
|
|
.El
|
|
.Sh EXIT STATUS
|
|
The
|
|
.Nm md5 , sha1 , sha224 , sha256 , sha512 , sha512t256 , rmd160 ,
|
|
.Nm skein256 , skein512 ,
|
|
and
|
|
.Nm skein1024
|
|
utilities exit 0 on success,
|
|
1 if at least one of the input files could not be read,
|
|
and 2 if at least one file does not have the same hash as the
|
|
.Fl c
|
|
option.
|
|
.Sh EXAMPLES
|
|
Calculate the MD5 checksum of the string
|
|
.Dq Hello .
|
|
.Bd -literal -offset indent
|
|
$ md5 -s Hello
|
|
MD5 ("Hello") = 8b1a9953c4611296a827abf8c47804d7
|
|
.Ed
|
|
.Pp
|
|
Same as above, but note the absence of the newline character in the input
|
|
string:
|
|
.Bd -literal -offset indent
|
|
$ echo -n Hello | md5
|
|
8b1a9953c4611296a827abf8c47804d7
|
|
.Ed
|
|
.Pp
|
|
Calculate the checksum of multiple files reversing the output:
|
|
.Bd -literal -offset indent
|
|
$ md5 -r /boot/loader.conf /etc/rc.conf
|
|
ada5f60f23af88ff95b8091d6d67bef6 /boot/loader.conf
|
|
d80bf36c332dc0fdc479366ec3fa44cd /etc/rc.conf
|
|
.Pd
|
|
The
|
|
.Nm -sum
|
|
variants put 2 blank characters between hash and file name for full compatibility
|
|
with the coreutils versions of these commands.
|
|
.Ed
|
|
.Pp
|
|
Write the digest for
|
|
.Pa /boot/loader.conf
|
|
in a file named
|
|
.Pa digest .
|
|
Then calculate the checksum again and validate it against the checksum string
|
|
extracted from the
|
|
.Pa digest
|
|
file:
|
|
.Bd -literal -offset indent
|
|
$ md5 /boot/loader.conf > digest && md5 -c $(cut -f2 -d= digest) /boot/loader.conf
|
|
MD5 (/boot/loader.conf) = ada5f60f23af88ff95b8091d6d67bef6
|
|
.Ed
|
|
.Pp
|
|
Same as above but comparing the digest against an invalid string
|
|
.Pq Dq randomstring ,
|
|
which results in a failure.
|
|
.Bd -literal -offset indent
|
|
$ md5 -c randomstring /boot/loader.conf
|
|
MD5 (/boot/loader.conf) = ada5f60f23af88ff95b8091d6d67bef6 [ Failed ]
|
|
.Ed
|
|
.Pp
|
|
If invoked with a name ending in
|
|
.Nm -sum
|
|
the
|
|
.Fl c
|
|
option does not compare against a hash string passed as parameter.
|
|
Instead, it expects a digest file, as created under the name
|
|
.Pa digest
|
|
for
|
|
.Pa /boot/loader.conf
|
|
in the example above.
|
|
.Bd -literal -offset indent
|
|
$ md5 -c digest /boot/loader.conf
|
|
/boot/loader.conf: OK
|
|
.Ed
|
|
.Pp
|
|
The digest file may contain any number of lines in the format generated with or without the
|
|
.Fl r
|
|
option
|
|
.Pq i.e., in either classical BSD format or in GNU coreutils format .
|
|
If a hash value does not match the file, FAILED is printed instead of OK.
|
|
.Sh SEE ALSO
|
|
.Xr cksum 1 ,
|
|
.Xr md5 3 ,
|
|
.Xr ripemd 3 ,
|
|
.Xr sha 3 ,
|
|
.Xr sha256 3 ,
|
|
.Xr sha384 3 ,
|
|
.Xr sha512 3 ,
|
|
.Xr skein 3
|
|
.Rs
|
|
.%A R. Rivest
|
|
.%T The MD5 Message-Digest Algorithm
|
|
.%O RFC1321
|
|
.Re
|
|
.Rs
|
|
.%A J. Burrows
|
|
.%T The Secure Hash Standard
|
|
.%O FIPS PUB 180-2
|
|
.Re
|
|
.Rs
|
|
.%A D. Eastlake and P. Jones
|
|
.%T US Secure Hash Algorithm 1
|
|
.%O RFC 3174
|
|
.Re
|
|
.Pp
|
|
RIPEMD-160 is part of the ISO draft standard
|
|
.Qq ISO/IEC DIS 10118-3
|
|
on dedicated hash functions.
|
|
.Pp
|
|
Secure Hash Standard (SHS):
|
|
.Pa https://www.nist.gov/publications/secure-hash-standard-shs
|
|
.Pp
|
|
The RIPEMD-160 page:
|
|
.Pa https://homes.esat.kuleuven.be/~bosselae/ripemd160.html
|
|
.Sh BUGS
|
|
All of the utilities that end in
|
|
.Sq sum
|
|
are intended to be compatible with the GNU coreutils programs.
|
|
However, the long option functionality is not provided.
|
|
.Sh ACKNOWLEDGMENTS
|
|
This program is placed in the public domain for free general use by
|
|
RSA Data Security.
|
|
.Pp
|
|
Support for SHA-1 and RIPEMD-160 has been added by
|
|
.An Oliver Eikemeier Aq Mt eik@FreeBSD.org .
|