SHA Perl 5 Extension Version 1.1

This is the Secure Hash Algorithm extension to Perl 5. I have used Perl
5.002 in making this extension; the interface was shamelessly copied
from the MD5 interface by Neil Winton <N.Winton@axion.bt.co.uk>. I hope
that it will work under 5.003 and later, but have not yet had a chance
to check this out.

To build the extension, unpack this distribution (presumably you have
already succeeded in doing this...), then type

    perl Makefile.PL	# create a Makefile
    make		# build the extension locally
    make install	# put it into the system directory

This creates a dynamically-linked extension. I don't have a target to
make a statically-linked perl, sorry. You should be able to unpack this
distribution in the ext/ subdirectory of the perl distribution, then
include SHA in the list of statically-linked extensions during
configuration of perl, but I have not tried that myself.

After you've installed the SHA extension, you should be able to type
'perl sha_driver.pl -x' to check if it all worked ok. If the actual
results don't match the expected ones, check that you have defined or
undefined LITTLE_ENDIAN properly for your machine, in sha_func.c. The
default is LITTLE_ENDIAN. By default, the first version of the SHA is
implemented. By defining USE_MODIFIED_SHA, also in sha_func.c, the
second version of the SHA can be used instead. The modification to the
SHA was made by NIST because of unspecified security concerns in the
first version. Since then, there have been some potential weaknesses
which have appeared in another secure hash algorithm, MD5 from RSA Data
Security Inc. It is possible that these changes to the SHA were
intended to address equivalent weaknesses in it. Please note that I
have no test results for that second version.

To see how to use the extension, look at sha_driver.pl or at SHA.pod.

This extension is available under the same copyright as Perl itself is.
The C sources in sha_func.c and in sha.h are in the public domain.

Please direct comments to me:
Uwe Hollerbach <uh@alumni.caltech.edu> or <uweh@bu.edu>