Wrong SHA1 is calculated
Hello, I am debugging a problem with SHA1 checksums. I have found the following handy one-liner on Stack Overflow [^1], which serves well as a minimal example: ``` perl -MDigest::SHA1=sha1_hex -le "print sha1_hex <>" secure.txt ``` The problem is, that the result is simply not correct. Doing the same on a Unix system gives the correct result. And I also get a correct result when I generate the SHA1 sum with the 7-zip file manager. Any ideas what the problem might be? [^1]: http://stackoverflow.com/a/2812212 Best regards, Martin Puppe JAM Software JAM Software GmbH Managing Director: Joachim Marder Am Wissenschaftspark 26 * 54296 Trier * Germany Phone: +49 (0)651-145 653 -0 * Fax: +49 (0)651-145 653 -29 Commercial register number HRB 4920 (AG Wittlich) http://www.jam-software.com JAM Software GmbH Gesch?ftsf?hrer: Joachim Marder Am Wissenschaftspark 26 * 54296 Trier * Germany Tel: 0651-145 653 -0 * Fax: 0651-145 653 -29 Handelsregister Nr. HRB 4920 (AG Wittlich) http://www.jam-software.de
Re: Wrong SHA1 is calculated
From: Martin Puppe
Sent: Monday, May 15, 2017 8:39 PM
To: win32-vanilla@perl.org
Subject: Wrong SHA1 is calculated
Hello,
I am debugging a problem with SHA1 checksums. I have found the following
handy one-liner on Stack Overflow [^1], which serves well as a minimal
example:
perl -MDigest::SHA1=sha1_hex -le "print sha1_hex <>" secure.txt
The problem is, that the result is simply not correct.Martin Puppe
The same web page presents a program which should provide the same "not
correct" result.
I've inserted "binmode $fh;" into it - which then allows it to return the
"correct" value:
#
use warnings;
use strict;
use Digest::SHA1;
die "Usage: $0 file ..\n" unless @ARGV;
foreach my $file (@ARGV) {
my $fh;
unless (open $fh, $file) {
warn "$0: open $file: $!";
next;
}
binmode $fh; # inserted by sisyphus
my $sha1 = Digest::SHA1->new;
$sha1->addfile($fh);
print $sha1->hexdigest, " $file\n";
close $fh;
}
###
If 'secure.txt' is a plain text file with Unix line endings, then that
binmode() should not be necessary - but if the text file has Windows line
endings then binmode() will prevent their translation to Unix endings (and
the program will return the result that you expect).
Unfortunately, I don't know how to get that binmode() into the one-liner's
angle brackets :-(
Maybe someone else here can chime in.
Cheers,
Rob
Re: Wrong SHA1 is calculated
-Original Message- From: Christian Millour Sent: Tuesday, May 16, 2017 9:14 AM To: win32-vanilla@perl.org Subject: Re: Wrong SHA1 is calculated Le 15/05/2017 à 16:30, sisyph...@optusnet.com.au a écrit : Unfortunately, I don't know how to get that binmode() into the one-liner's angle brackets :-( $ PERLIO=unix perl -MDigest::SHA1=sha1_hex -le "print sha1_hex <>" secure.txt 19576d392b021ac25efdca6f1886b5ce5b1090c4 $ Yes, I think that should give the OP the result he was seeking. Nice. Cheers, Rob
Re: Wrong SHA1 is calculated
Le 15/05/2017 à 16:30, sisyph...@optusnet.com.au a écrit :
Unfortunately, I don't know how to get that binmode() into the
one-liner's angle brackets :-(
you might consider playing with the PERLIO environment variable :
$ perl -E "print qq{hello\nworld\n}" > secure.txt
$ od -c secure.txt
000 h e l l o \r \n w o r l d \r \n
016
$ perl -MDigest::SHA1=sha1_hex -le "print sha1_hex <>" secure.txt
58853e8a5e8272b1012f9a52a80758b27bd0d3cb
$ PERLIO=unix perl -MDigest::SHA1=sha1_hex -le "print sha1_hex <>"
secure.txt
19576d392b021ac25efdca6f1886b5ce5b1090c4
$
--Christian
