1sha512hmac(8) System Administrator's Manual sha512hmac(8)
2
6 sha512hmac - compute and check HMAC values
7
10 sha512hmac [OPTIONS] [-u | -k keyfile | -K key] [-c file [-q] | file
11 [...] ]
12
15 The sha512hmac command can compute and/or verify HMAC and unkeyed
16 checksum values for the contents of files. Variations such as
17 sha384hmac, sha256hmac, and sha1hmac all operate similarly except that
18 they use different digest algorithms.
19
22 As a safety measure, the tool will always attempt to verify a previ‐
23 ously- computed HMAC over itself with the contents of a second file
24 (sha512hmac.hmac for sha512hmac, and a similarly-named file for each
25 variation) before processing any other files, and will exit with an
26 error if the second file either cannot be read or does not match the
27 computed value.
28
31 -c Check that the HMAC values and names listed in the specified
32 file(s) are correct for the files which are available. The for‐
33 mat of the files should match the output which the tool produces
34 when computing the values: a hex-encoded HMAC value and then a
35 filename, separated by whitespace.
36 -q Suppress any output when checking values.
38 -d cfgdir
40 Specify the configuration directory to be used by the NSS
41 library. The default location is /etc/pki/nssdb.
42 -h algorithm
44 Generate the HMAC value using a non-default hashing algorithm.
45 The default is determined by the name used to invoke the tool
46 (sha1hmac, sha256hmac, etc.). If no default can be derived this
47 way, the default setting will be sha512. Specify help or
48 another invalid value to obtain a list of recognized algorithms.
49 -u Generate an unkeyed checksum instead of an HMAC. The output
51 produced by the tool should then be comparable to that of
52 sha1sum and related tools.
53 -k filename
55 Use the contents of the specified file as the secret key used in
56 computing the HMAC values. If no key file or text is specified,
57 a hard-coded default value is used. This option should always
58 be used.
59 -K text
61 Use the text of the argument as the secret key used in computing
62 the HMAC values. If no key file or text is specified, a hard-
63 coded default value is used.
64 -b Process file contents in binary mode, marking output as such by
66 prefixing filenames with *. This option is not expected to have
67 any other meaningful effect.
68 -t bits
70 Truncate HMAC values to a given length when computing or verify‐
71 ing them.
72 -S Generate an HMAC over the tool itself and output it on standard
74 out. This is a bootstrapping option which is not expected to be
75 used.
76 -P Attempt to pass all input files through prelink -y before pro‐
78 cessing their contents. The tool always attempts to do so when
79 computing or performing a self-check.
80
84 Example output from sha1hmac, for files on the developer's system:
85 e64db5e8a9b8a40091e5302fa4de0bfc6c5d19d0 /etc/passwd
86 e7d93a2c70ec4d7720c6f2b033c1e5ea19f2d677 /etc/group
87 d732d6df77114ea6b81a43d64655f86b1e5ee925 /etc/services
88 ad92162bef979054a75d1f3510e6b05902bec641 /etc/hosts
89
92 fipshmac(1), fipscheck(1), prelink(8)
93
96 Probably, but let's hope not. If you find any, please either report
97 them in the bug database at http://bugzilla.redhat.com/ against the
98 "hmaccalc" component, or in the trac instance at https://fedora‐
99 hosted.org/hmaccalc/.
100
103 Nalin Dahyabhai <nalin@redhat.com>
104hmaccalc 0.9.13 2009/03/19 sha512hmac(8)