diff --git a/ecdsa.pm b/ecdsa.pm
index 962b6a7..9368b28 100644
--- a/ecdsa.pm
+++ b/ecdsa.pm
@@ -213,20 +213,29 @@ sub pub_decode {
 
 sub hash_decode {
 	my ($hash) = @_;
-
-	my $s = length ($hash) * 8 - $EC_SIZE;
+    my $s = length ($hash) * 8 - $EC_SIZE;
 	my $e = i_decode ($hash);
 	$e = $e->brsft ($s) if $s > 0;
 	return $e;
 }
 
+sub ber_hex {
+    # like i_encode() but doesn't attempt to pad it out to any length and makes sure there is a leading null if otherwise the first high bit would be set (which would indicate negative, but these are never neg)
+    # standardizing on exactly this formatting of numbers was the main part of the "canonicalization" fix for the transaction mutability bug
+    my $i = shift;
+    my $bin = $i->as_hex;
+    $bin =~ s/^0x// or die $i;
+    $bin = '00' . $bin if hex( substr($bin, 0, 2) ) >= 0x80;
+	return pack 'H*', $bin;
+}
+
 sub sig_encode {
 	my ($sig) = @_;
 
 	my ($r, $s) = @$sig;
-	return pack 'C w/a', 0x30,
-		pack ('C w/a', 0x02, i_encode ($r)) .
-		pack ('C w/a', 0x02, i_encode ($s));
+	return pack 'C C/a', 0x30,
+		pack ('C C/a', 0x02, ber_hex($r) ) .
+		pack ('C C/a', 0x02, ber_hex($s) );
 }
 
 sub sig_decode {
diff --git a/test/ecdsa b/test/ecdsa
index c4cbac7..05406ef 100644
--- a/test/ecdsa
+++ b/test/ecdsa
@@ -1,50 +1,65 @@
-#! /usr/bin/perl -l
-BEGIN { chdir '..' }
-
-use warnings;
-use strict;
-
-use ecdsa;
-
-$ecdsa::PROB_VERIFY = 1;
-
-print ecdsa::version;
-
-ecdsa::p_oncurve ([
-	ecdsa::i '0x11db93e1dcdb8a016b49840f8c53bc1eb68a382e97b1482ecad7b148a6909a5c',
-	ecdsa::i '0xb2e0eaddfb84ccf9744464f82e160bfa9b8b64f9d4c03f999b8643f656b412a3',
-]) or die;
-print "ok 1";
-
-ecdsa::ec_verify ([
-	ecdsa::i '0x11db93e1dcdb8a016b49840f8c53bc1eb68a382e97b1482ecad7b148a6909a5c',
-	ecdsa::i '0xb2e0eaddfb84ccf9744464f82e160bfa9b8b64f9d4c03f999b8643f656b412a3',
-], ecdsa::hash_decode (pack 'H*',
-	    '7a05c6145f10101e9d6325494245adf1297d80f8f38d4d576d57cdba220bcb19',
-), [
-	ecdsa::i '0x4e45e16932b8af514961a1d3a1a25fdf3f4f7732e9d624c6c61548ab5fb8cd41',
-	ecdsa::i '0x181522ec8eca07de4860a4acdd12909d831cc56cbbac4622082221a8768d1d09',
-]) or die;
-print "ok 2";
-
-my $k = ecdsa::GenKey ();
-my $h = 123;
-my $s = ecdsa::Sign ($k, $h);
-ecdsa::Verify ($k, $h, $s) or die;
-print "ok 3";
-
-while (<DATA>) {
-	my ($p, $h, $s) = /(\S+) (\S+) (\S+)/ or die;
-	$_ = pack 'H*', $_ for $p, $h, $s;
-	ecdsa::Verify ({ pub => $p }, $h, $s) or die $_;
-	print "ok";
-}
-
-__DATA__
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-04987df80fccecc297c66f84821279648f0868ca30beea4231eb7bf189071055abbf61a75469d379ae09245ebb39d584d9f67a83130ee95c45bd76b5d9e01aa7aa 17e5410cd8db696e37aaae85d3e687852305ac9540d553dc414fd362bdaf2dd6 3045022038d52df4f8a494be36aee617ca5fb28e585895190fa58e5aba199ccf1c90371b022100bb2960426f8e196d9a42fb02579f85ae26ab9956918241bd77f02bb6dfab3a6a
+#! /usr/bin/perl -l
+BEGIN { chdir '..' }
+
+use warnings;
+use strict;
+
+use ecdsa;
+
+$ecdsa::PROB_VERIFY = 1;
+
+print ecdsa::version;
+
+ecdsa::p_oncurve ([
+	ecdsa::i '0x11db93e1dcdb8a016b49840f8c53bc1eb68a382e97b1482ecad7b148a6909a5c',
+	ecdsa::i '0xb2e0eaddfb84ccf9744464f82e160bfa9b8b64f9d4c03f999b8643f656b412a3',
+]) or die;
+print "ok 1";
+
+ecdsa::ec_verify ([
+	ecdsa::i '0x11db93e1dcdb8a016b49840f8c53bc1eb68a382e97b1482ecad7b148a6909a5c',
+	ecdsa::i '0xb2e0eaddfb84ccf9744464f82e160bfa9b8b64f9d4c03f999b8643f656b412a3',
+], ecdsa::hash_decode (pack 'H*',
+	    '7a05c6145f10101e9d6325494245adf1297d80f8f38d4d576d57cdba220bcb19',
+), [
+	ecdsa::i '0x4e45e16932b8af514961a1d3a1a25fdf3f4f7732e9d624c6c61548ab5fb8cd41',
+	ecdsa::i '0x181522ec8eca07de4860a4acdd12909d831cc56cbbac4622082221a8768d1d09',
+]) or die;
+print "ok 2";
+
+my $k = ecdsa::GenKey ();
+my $h = 123;
+
+use Data::Dumper;
+# warn Dumper $k;
+
+my $s = ecdsa::Sign ($k, $h);
+ecdsa::Verify ($k, $h, $s) or die;
+print "ok 3";
+
+# test that DER encoded strings are correctly conicalized when generating ASN.1 encoded signitures
+
+$k = { priv => from_hex('313032373533323531323539343134313833383035303734333633333334323835323731373732313039363835353931393535383338383833343439313231383132383635343632323238343132') };
+$h = from_hex('3939363234303634303238353836333033343037373931303937393038383131303238343535373730383533333735323730343932343437383735303330383235333634313733373734343532');
+$s = ecdsa::Sign( $k, $h );
+print "ok 4" if $s eq from_hex('30460221009bb961c94162063af38f24fc058f66144d723f16a1896612151f763984e8e8750221009c8b8aa577b5a72b5e32114983c0c0bd02a788ea70c91fb49138b44945a99b00');
+
+while (<DATA>) {
+	my ($p, $h, $s) = /(\S+) (\S+) (\S+)/ or die;
+	$_ = pack 'H*', $_ for $p, $h, $s;
+	ecdsa::Verify ({ pub => $p }, $h, $s) or die $_;
+	print "ok";
+}
+
+sub from_hex {
+    pack( "H*", $_[0] );
+}
+
+__DATA__
+04c22551f7ada4ff0652684301e2a96748b6ab3371ee0cf574734f81a46cb43ca524a75b25c8e63243d46da91c9086dd5a7fc52112ae3853f7950a3f1e17fb664f a194083fee9582252f32bd8dabd226785725d1e7e178c1c5dd702bc8500a4bd5 304502202f9ef0928d14d3e8d8d38b84789dfee5fb2ad22d55e4198e9d3521c8cfe5a911022100f72915c2093025ae9e74da59bb9582476519b014bef9f9afa8e7892db0df701a
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