[Jifty-commit] r1551 - Jifty-DBI/trunk/lib/Jifty/DBI/Filter

[jifty-commit at lists.jifty.org]

Author: nelhage
Date: Thu Jul 13 13:02:08 2006
New Revision: 1551

Added:
   Jifty-DBI/trunk/lib/Jifty/DBI/Filter/SaltHash.pm

Log:
Adding a filter to salt and hash passwords

Added: Jifty-DBI/trunk/lib/Jifty/DBI/Filter/SaltHash.pm
==============================================================================
--- (empty file)
+++ Jifty-DBI/trunk/lib/Jifty/DBI/Filter/SaltHash.pm	Thu Jul 13 13:02:08 2006
@@ -0,0 +1,89 @@
+package Jifty::DBI::Filter::SaltHash;
+
+use warnings;
+use strict;
+
+use base qw|Jifty::DBI::Filter|;
+use Digest::MD5 qw(md5_hex);
+
+=head1 NAME
+
+Jifty::DBI::Filter::SaltHash - salts and hashes a value before storing it
+
+=head1 DESCRIPTION
+
+This filter will generate a random 4-byte salt, and then MD5 the given
+value with the salt appended to the value. It will store the hash and
+the salt in the database, and return a data structure that contains
+both on decode. The salt and hash are stored in hexadecimal in the
+database, so that you can put them in a text field.
+
+This filter is intended for storing passwords in a database.
+
+=head2 encode
+
+Generate a random 4-byte salt, MD5 the value with the salt (encoded to
+hexadecimal) appended to it, and store both in the database.
+
+=cut
+
+sub encode {
+    my $self = shift;
+    my $value_ref = $self->value_ref;
+
+    return unless defined $$value_ref;
+
+    my $salt = generate_salt();
+
+    $$value_ref = md5_hex($$value_ref, $salt) . $salt;
+}
+
+=head2 generate_salt
+
+Return a random 4-byte salt value, encoded as an 8-character hex
+string.
+
+=cut
+
+sub generate_salt {
+    my $salt;
+    $salt .= unpack('H2',chr(int rand(255))) for(1..4);
+    return $salt;
+}
+
+=head2 decode
+
+Return an arrayref of (hash, salt), both as hex strings.
+
+To test whether a provided value is the same one originally encoded,
+use
+
+    $hash eq md5_hex($value . $salt);
+
+=cut
+
+sub decode {
+    my $self = shift;
+    my $value_ref = $self->value_ref;
+
+    return unless $$value_ref;
+
+    # This should never happen, but just to be safe
+    unless(length($$value_ref) == (8 + 32)) {
+        $$value_ref = [undef, undef];
+    } else {
+        $$value_ref = [unpack("A32A8", $$value_ref)];
+    }
+
+    return 1;
+}
+
+
+
+=head1 SEE ALSO
+
+L<Jifty::DBI::Filter>, L<Digest::MD5>
+
+=cut
+
+1;