diff --git a/2016/04/1.pl b/2016/04/1.pl
new file mode 100644
index 0000000..9a3b836
--- /dev/null
+++ b/2016/04/1.pl
@@ -0,0 +1,17 @@
+use 5.20.0;
+
+use List::UtilsBy qw/ sort_by /;
+use List::AllUtils qw/ sum /;
+use experimental qw/ signatures /;
+
+
+say sum map { /(\d+)/ } grep { is_real($_) } <>;
+
+sub is_real ( $line ) {
+    $line =~ s/\[(.*?)\]//;
+    my $checksum = $1;
+
+    $checksum eq join '', ( sort_by { 
+        sprintf "%03d%s", 999 - (eval "\$line =~ y/$_/$_/"), $_
+    } 'a'..'z' )[0..4];
+}
diff --git a/2016/04/2.pl b/2016/04/2.pl
new file mode 100644
index 0000000..2a2d594
--- /dev/null
+++ b/2016/04/2.pl
@@ -0,0 +1,32 @@
+use 5.20.0;
+
+use List::UtilsBy qw/ sort_by /;
+use List::AllUtils qw/ sum /;
+use experimental qw/ signatures /;
+
+my @real = grep { is_real($_) } <>;
+
+my @alphabet = ( 'a'..'z' );
+say $_, ": ", decrypt($_) for @real;
+
+
+sub decrypt($line) {
+
+    $line =~ s/(\d+).*$//;
+    my $checksum = $1;
+
+    $line =~ s/-/ /g;
+    $line =~ s/([a-z])/ $alphabet[ ( ord( $1 ) - ord( 'a' ) + $checksum ) % @alphabet ]/eg;
+
+    $line;
+
+}
+
+sub is_real ( $line ) {
+    $line =~ s/\[(.*?)\]//;
+    my $checksum = $1;
+
+    $checksum eq join '', ( sort_by { 
+        sprintf "%03d%s", 999 - (eval "\$line =~ y/$_/$_/"), $_
+    } 'a'..'z' )[0..4];
+}