SHA(1)

NAME
sha - Secure Hash Algorithm

SYNOPSIS
sha [-vt] [filename]...

DESCRIPTION
Sha calculates the NIST Secure Hash Algorithm defined in FIPS 180. For each file in the list it produces 160 bits of hash, formatted as 40 hex digits. The "-v" flag causes sha to print the filename as well as the hash. The "-t" flag suppresses the spaces between 32-bit groups. If no file is specified, it processes the standard input.

NIST suggests using the Secure Hash Algorithm as a message digesting function, producing a message-dependent fixed-size block that may be securely signed with a digital signature system such as NIST's DSS. Quoting from the draft standard, "The SHA is designed to have the following properties: it is computationally infeasible to recover a message corresponding to a given message digest, or to find two different messages which produce the same message digest."

It may also be used as an ordinary file checksum.

SEE ALSO
sum(1), sha_file(3), FIPS 180

BUGS
NIST defines SHA for arbitrary bit strings. This implementation operates only at the byte level.

AUTHOR
Jim Gillogly