Here's a little script that I put together to help you get going. Instead of SHA1, I use SHA-256---for me, it's better and stronger than SHA1; also, for AES-128-ECB, I used Crypt::CBC with a Rijndael cipher in MODE_ECB, rijndael_compat. Give it a try.

#!/usr/bin/perl -l

use strict;
use warnings;
use CPAN;
use Crypt::CBC;
use Crypt::Rijndael;
use Data::Translate;
use Data::Dumper::Concise;
use MIME::Base64 qw(encode_base64);
use Digest::SHA qw(sha256_hex sha256_base64);

$| = 1;

CPAN::Shell->install(qw(
Crypt::CBC
Crypt::Rijndael
Data::Translate
Data::Dumper::Concise
Digest::SHA
MIME::Base64));

print "=" x 72;
print "Converting  ascii to hex: ";
my $data = new Data::Translate;
my @aa   = qw(hello_world);
my ( $s, @ah ) = $data->a2h(@aa);
binmode STDOUT, ":encoding(utf8)";
print "\t", join( '', @ah );
print "=" x 72;

print "Converting hex to ascii:";
my $data2 = new Data::Translate;
my @hh    = qw(68 65 6c 6c 6f 5f 77 6f 72 6c 64);
my ( $s2, @ha2 ) = $data2->h2a(@hh);
binmode STDOUT, ":encoding(utf8)";
print "\t", join( '', @ha2 );
print "=" x 72;

print "Calculating sha256_hex digest for hex: ";
my $data3 = '68 65 6c 6c 6f 5f 77 6f 72 6c 64';
print "\t", sha256_hex($data3);
print "=" x 72;

print "Calculating sha256_hexdigest for hello_world: ";
my $data4 = qw(hello_world);
print "\t", sha256_hex($data4);
print "=" x 72;

print "Calculating sha256_base64 for hello_world: ";
my $data5 = qw(hello_world);
local ($/) = undef;
print "\t", encode_base64($data5);
print "=" x 72;

my $bs = Crypt::Rijndael->blocksize;
my $ks = Crypt::Rijndael->keysize;

my $cipher = Crypt::CBC->new(
    -key         => 'a' x $ks,
    -iv          => 'f' x $bs,
    -literal_key => 1,
    -cipher      => 'Rijndael',
    -header      => 'none',
    -padding     => 'rijndael_compat',
);

my $in = <<"END";
hello_world
END

my $j = Crypt::Rijndael->new( 'a' x $ks, Crypt::Rijndael->MODE_ECB );
$j->set_iv( 'f' x $bs );
$cipher->start('encrypting');
if ($in) {
    my $string = 'a' x 32;
    binmode STDOUT, ":encoding(UTF-8)";
    my $encrypt = $cipher->encrypt($string);
    my $decrypt = $cipher->decrypt($encrypt);
    print "Testing MODE_ECB: ";
    print "\t", Dumper("$decrypt");
}
$cipher->finish;
[download]

References:

Crypt::CBC
Crypt::Rijndael
Data::Translate
Data::Dumper::Concise
MIME::Base64
Digest::SHA