MirOS Manual: sha1(1)

SHA1(1)                      BSD Reference Manual                      SHA1(1)

NAME

     sha1 - calculate a message-digest fingerprint (checksum) for a file

SYNOPSIS

     sha1 [-b] [-p | -s string | file ...]
     sha1 -G [file ...]
     sha1 -t | -x | -c [checklist ...]
     sha1sum [-b | -t] [file ...]

DESCRIPTION

     sha1 takes as input a message of arbitrary length and produces as output
     a 160-bit "fingerprint" or "message digest" of the input. It is conjec-
     tured that it is computationally infeasible to produce two messages hav-
     ing the same message digest, or to produce any message having a given
     prespecified target message digest.

     The SHA-1 algorithm is intended for digital signature applications, where
     a large file must be "compressed" in a secure manner before being en-
     crypted with a private (secret) key under a public-key cryptosystem such
     as RSA. However, recently the SHA family's (SHA-0, SHA-1, SHA-2 (SHA-384
     and SHA-512) all share the same design) weakness has been proven in re-
     duced versions of SHA-1 and partially SHA-2 and collisions for SHA-1 can
     be found. The use of other hash functions is encouraged; however, as
     RIPEMD-160 is only little more secure, combining hashes from different
     families or, better, different approaches (Tiger, Whirlpool) is recom-
     mended.

     The options are as follows:

     -b      Print the checksum as binary to stdout. Ignored in GNU mode.

     -c [checklist ...]
             Compares all checksums contained in the file checklist with newly
             computed checksums for the corresponding files. Output consists
             of the digest used, the file name, and an OK or FAILED for the
             result of the comparison. This will validate any of the supported
             checksums (see cksum(1)). If no file is given, stdin is used.

     -G      Enable GNU md5sum compatible output mode. Can also be enabled by
             calling this programme as sha1sum.

     -p      Echoes stdin to stdout and appends the SHA-1 sum to stdout.

     -s string
             Prints a checksum of the given string.

     -t      Runs a built-in time trial. Ignored in GNU mode.

     -x      Runs a built-in test script.

     The SHA-1 sum of each file listed on the command line is printed after
     the options are processed.

     The sha1 command is shorthand for

           cksum -a sha1

     The cksum(1) command can also be used to compute digests from the SHA-2
     family: sha256, sha384 and sha512.

SEE ALSO

     cksum(1), md5(1), rmd160(1)

     J. Burrows, The Secure Hash Standard, FIPS PUB 180-1.
     D. Eastlake and P. Jones, US Secure Hash Algorithm 1, RFC 3174.

MirOS BSD #10-current         November 17, 2009                              1

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