SHA1(1)                    OpenBSD Reference Manual                    SHA1(1)

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

SYNOPSIS
     sha1 [-bpqrtx] [-c [checklist ...]] [-s string] [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.

     The options are as follows:

     -b      Output checksums in base64 notation, not hexadecimal.

     -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 support-
             ed checksums (see cksum(1)).  If no file is given, stdin is used.

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

     -q      Only print the checksum (quiet mode).

     -r      Reverse the format of the hash algorithm output, making it match
             the output format used by cksum(1).

     -s string
             Prints a checksum of the given string.

     -t      Runs a built-in time trial.  Specifying -t multiple times results
             in the number of rounds being multiplied by 10 for each addition-
             al flag.

     -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.

     The sha1 utility exits 0 on success, and >0 if an error occurs.

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.

OpenBSD 4.7                      May 31, 2007                                1
