Try bypassing the backtick operator and use IPC::Open2

#!/usr/bin/perl

use Digest::SHA1;
use IPC::Open2;

use strict;
use warnings;

my $text  = "deepak.gulati";
my $hash1 = do_openssl( $text );
my $hash2 = Digest::SHA1::sha1_hex( $text );

print $hash1, "\n";
print $hash2, "\n";

sub do_openssl {
  my $text = shift;

  open2( my $rfh, my $wfh, 'openssl dgst -sha1' ) || die "cannot open:
+ $!\n";
  print $wfh $text;
  close( $wfh );
  my $value = <$rfh>;
  close( $rfh );

  chomp( $value );
  return $value;
}
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Thanks a ton! This gave identical result for $hash1 and $hash2. Any idea why backticks are problematic here?