package Palm::Keyring;
# $RedRiver: Keyring.pm,v 1.31 2007/02/19 02:55:35 andrew Exp $
########################################################################
# Keyring.pm *** Perl class for Keyring for Palm OS databases.
#
#   This started as Memo.pm, I just made it work for Keyring.
#
# 2006.01.26 #*#*# andrew fresh <andrew@cpan.org>
########################################################################
# Copyright (C) 2006, 2007 by Andrew Fresh
#
# This program is free software; you can redistribute it and/or modify
# it under the same terms as Perl itself.
########################################################################
use strict;
use warnings;

use Carp;

use base qw/ Palm::StdAppInfo /;

my $ENCRYPT    = 1;
my $DECRYPT    = 0;
my $MD5_CBLOCK = 64;
my $kSalt_Size = 4;
my $EMPTY      = q{};
my $SPACE      = q{ };
my $NULL       = chr 0;

my @CRYPTS = (
    { # None
        name      => 'None',
        keylen    => 8,
        blocksize => 1,
        default_iter => 500,
    },
    { # DES-EDE3
        name      => 'DES_EDE3',
        keylen    => 24,
        blocksize =>  8,
        DES_odd_parity => 1,
        default_iter => 1000,
    },
    { # AES128
        name      => 'Rijndael',
        keylen    => 16,
        blocksize => 16,
        default_iter => 100,
    },
    { # AES256
        name      => 'Rijndael',
        keylen    => 32,
        blocksize => 16,
        default_iter => 250,
    },
);


our $VERSION = 0.95;

sub new 
{
    my $classname = shift;
    my $options = {};

    # hashref arguments
    if (ref $_[0] eq 'HASH') {
      $options = shift;
    }

    # CGI style arguments
    elsif ($_[0] =~ /^-[a-zA-Z0-9_]{1,20}$/) {
      my %tmp = @_;
      while ( my($key,$value) = each %tmp) {
        $key =~ s/^-//;
        $options->{lc $key} = $value;
      }
    }

    else {
        $options->{password} = shift;
        $options->{version}  = shift;
    }

    # Create a generic PDB. No need to rebless it, though.
    my $self = $classname->SUPER::new();

    $self->{name}    = 'Keys-Gtkr';    # Default
    $self->{creator} = 'Gtkr';
    $self->{type}    = 'Gkyr';

    # The PDB is not a resource database by
    # default, but it's worth emphasizing,
    # since MemoDB is explicitly not a PRC.
    $self->{attributes}{resource} = 0;

    # Set the version
    $self->{version} = $options->{version} || 4;

    # Set options
    $self->{options} = $options;

    # Set defaults
    if ($self->{version} == 5) {
        $self->{options}->{cipher} ||= 0; # 'None'
        $self->{options}->{iterations} ||= 
            $CRYPTS[ $self->{options}->{cipher} ]{default_iter};

       $self->{appinfo}->{cipher} ||= $self->{options}->{cipher};
       $self->{appinfo}->{iter}   ||= $self->{options}->{iterations};
    };

    if ( defined $options->{password} ) {
        $self->Password($options->{password});
    }

    return $self;
}

sub import 
{
    Palm::PDB::RegisterPDBHandlers( __PACKAGE__, [ 'Gtkr', 'Gkyr' ], );
    return 1;
}

# ParseRecord

sub ParseRecord 
{
    my $self     = shift;

    my $rec = $self->SUPER::ParseRecord(@_);
    return $rec if ! exists $rec->{data};

    if ($self->{version} == 4) {
        # skip the first record because it contains the password.
        return $rec if ! exists $self->{records}; 

        my ( $name, $encrypted ) = split /$NULL/xm, $rec->{data}, 2;

        return $rec if ! $encrypted;
        $rec->{name}      = $name;
        $rec->{encrypted} = $encrypted;
        delete $rec->{data};

    } elsif ($self->{version} == 5) {
        my $blocksize = $CRYPTS[ $self->{appinfo}->{cipher} ]{blocksize};
        my ($field, $extra) = _parse_field($rec->{data});
        my $ivec      = substr $extra, 0, $blocksize;
        my $encrypted = substr $extra, $blocksize;

        $rec->{name}      = $field->{data};
        $rec->{ivec}      = $ivec;
        $rec->{encrypted} = $encrypted;

    } else {
        die 'Unsupported Version';
        return;
    }

    return $rec;
}

# PackRecord

sub PackRecord 
{
    my $self = shift;
    my $rec  = shift;

    if ($self->{version} == 4) {
        if ($rec->{encrypted}) {
            if (! defined $rec->{name}) {
                $rec->{name} = $EMPTY;
            }
            $rec->{data} = join $NULL, $rec->{name}, $rec->{encrypted};
            delete $rec->{name};
            delete $rec->{encrypted};
        }

    } elsif ($self->{version} == 5) {
        my $field = {
            'label_id' => 1,
            'data'     => $rec->{name},
            'font'     => 0,
        };
        my $packed .= _pack_field($field);

        $rec->{data} = join '', $packed, $rec->{ivec}, $rec->{encrypted};

    } else {
        die 'Unsupported Version';
    }

    return $self->SUPER::PackRecord($rec, @_);
}

# ParseAppInfoBlock

sub ParseAppInfoBlock 
{
    my $self = shift;
    my $data = shift;
    my $appinfo = {};

    &Palm::StdAppInfo::parse_StdAppInfo($appinfo, $data);

    # int8/uint8 
    # - Signed or Unsigned Byte (8 bits). C types: char, unsigned char
    # int16/uint16 
    # - Signed or Unsigned Word (16 bits). C types: short, unsigned short
    # int32/uint32 
    # - Signed or Unsigned Doubleword (32 bits). C types: int, unsigned int
    # sz 
    # - Zero-terminated C-style string 

    if ($self->{version} == 4) {
        # Nothing extra for version 4

    } elsif ($self->{version} == 5) {
        _parse_appinfo_v5($appinfo) || return;

    } else {
        die "Unsupported Version";
        return;
    }

    return $appinfo;
}

sub _parse_appinfo_v5
{
    my $appinfo = shift;

    if (! exists $appinfo->{other}) {
        # XXX Corrupt appinfo?
        return;
    }

    my $unpackstr
        = ("C1" x 8)  # 8 uint8s in an array for the salt
        . ("S1" x 2)  # the iter (uint16) and the cipher (uint16)
        . ("C1" x 8); # and finally 8 more uint8s for the hash

    my (@salt, $iter, $cipher, @hash);
    (@salt[0..7], $iter, $cipher, @hash[0..7]) 
        = unpack $unpackstr, $appinfo->{other};

    $appinfo->{salt}           = sprintf "%02x" x 8, @salt;
    $appinfo->{iter}           = $iter;
    $appinfo->{cipher}         = $cipher;
    $appinfo->{masterhash}     = sprintf "%02x" x 8, @hash;
    delete $appinfo->{other};

    return $appinfo
}

# PackAppInfoBlock

sub PackAppInfoBlock 
{
    my $self = shift;
    my $retval;

    if ($self->{version} == 4) {
        # Nothing to do for v4

    } elsif ($self->{version} == 5) {
        _pack_appinfo_v5($self->{appinfo});
    } else {
        die "Unsupported Version";
        return;
    }
    return &Palm::StdAppInfo::pack_StdAppInfo($self->{appinfo});
}

sub _pack_appinfo_v5
{
    my $appinfo = shift;

    my $packstr
        = ("C1" x 8)  # 8 uint8s in an array for the salt
        . ("S1" x 2)  # the iter (uint16) and the cipher (uint16)
        . ("C1" x 8); # and finally 8 more uint8s for the hash

    my @salt = map { hex $_ } $appinfo->{salt} =~ /../gxm;
    my @hash = map { hex $_ } $appinfo->{masterhash} =~ /../gxm;

    my $packed = pack($packstr, 
        @salt,
        $appinfo->{iter},
        $appinfo->{cipher},
        @hash
    );

    $appinfo->{other}  = $packed;

    return $appinfo
}

# Encrypt

sub Encrypt 
{
    my $self = shift;
    my $rec  = shift;
    my $data = shift;
    my $pass = shift || $self->{password};

    if ( ! $pass && ! $self->{appinfo}->{key}) {
        croak("password not set!\n");
    }

    if ( ! $rec) {
        croak("Needed parameter 'record' not passed!\n");
    }

    if ( ! $data) {
        croak("Needed parameter 'data' not passed!\n");
    }

    if ( $pass && ! $self->Password($pass)) {
        croak("Incorrect Password!\n");
    }

    my $acct;
    if ($rec->{encrypted}) {
        $acct = $self->Decrypt($rec, $pass);
    }

    my $encrypted;
    if ($self->{version} == 4) {
        $self->{digest} ||= _calc_keys( $pass );
        $encrypted = _encrypt_v4($data, $acct, $self->{digest});
        $rec->{name}    ||= $data->{name};

    } elsif ($self->{version} == 5) {
        my @recs = ($data, $acct);
        my $name;
        if ($self->{options}->{v4compatible}) {
            $rec->{name} ||= $data->{name};
            foreach my $rec (@recs) {
                my @fields;
                foreach my $k (sort keys %{ $rec }) {
                    my $field = {
                        label    => $k,
                        font     => 0,
                        data     => $rec->{$k},
                    };
                    push @fields, $field;
                }
                $rec = \@fields;
            }
        }

        my $ivec;
        ($encrypted, $ivec) = _encrypt_v5(
            @recs,
            $self->{appinfo}->{key}, 
            $self->{appinfo}->{cipher},
        );
        if ($ivec) {
            $rec->{ivec} = $ivec;
        }

    } else {
        die "Unsupported Version";
    }

    if ($encrypted) { 
        if ($encrypted eq '1') {
            return 1;
        }

        $rec->{attributes}{Dirty} = 1;
        $rec->{attributes}{dirty} = 1;
        $rec->{encrypted} = $encrypted;

        return 1;
    } else {
        return;
    }
}

sub _encrypt_v4 
{
    require Crypt::CBC;

    my $new    = shift;
    my $old    = shift;
    my $digest = shift;

    $new->{account}  ||= $EMPTY;
    $new->{password} ||= $EMPTY;
    $new->{notes}    ||= $EMPTY;

    my $changed      = 0;
    my $need_newdate = 0;
    if ($old && %{ $old }) {
        foreach my $key (keys %{ $new }) {
            next if $key eq 'lastchange';
            if ($new->{$key} ne $old->{$key}) {
                $changed = 1;
                last;
            }
        }
        if ( exists $new->{lastchange} && exists $old->{lastchange} && (
            $new->{lastchange}->{day}   != $old->{lastchange}->{day}   ||
            $new->{lastchange}->{month} != $old->{lastchange}->{month} ||
            $new->{lastchange}->{year}  != $old->{lastchange}->{year}
        )) {
            $changed = 1;
            $need_newdate = 0;
        } else {
            $need_newdate = 1;
        }

    } else {
        $changed = 1;
    }

    # no need to re-encrypt if it has not changed.
    return 1 if ! $changed;

    my ($day, $month, $year);

    if ($new->{lastchange} && ! $need_newdate ) {
        $day   = $new->{lastchange}->{day}   || 1;
        $month = $new->{lastchange}->{month} || 0;
        $year  = $new->{lastchange}->{year}  || 0;

        # XXX Need to actually validate the above information somehow
        if ($year >= 1900) {
            $year -= 1900;
        }
    } else {
        $need_newdate = 1;
    }

    if ($need_newdate) {
        ($day, $month, $year) = (localtime)[3,4,5];
    }

    my $packed_date = _pack_keyring_date( {
            year  => $year,
            month => $month,
            day   => $day,
    });

    my $plaintext = join $NULL, 
        $new->{account}, $new->{password}, $new->{notes}, $packed_date;

    return _crypt3des( $plaintext, $digest, $ENCRYPT );
}

sub _encrypt_v5
{
    my $new    = shift;
    my $old    = shift;
    my $key    = shift;
    my $cipher = shift;
    my $length = $CRYPTS[ $cipher ]{blocksize};
    my $ivec   = shift || pack("C*",map {rand(256)} 1..$length);

    my $keylen      = $CRYPTS[ $cipher ]{keylen}; 
    my $cipher_name = $CRYPTS[ $cipher ]{name};

    my $changed = 0;
    my $need_newdate = 1;
    my $date_index;
    for (my $i = 0; $i < @{ $new }; $i++) {
        if (
            (exists $new->[$i]->{label_id} && $new->[$i]->{label_id} == 3) ||
            (exists $new->[$i]->{label}    && $new->[$i]->{label}    eq 'lastchange')
        ) {
            $date_index   = $i;
            if ( $old && $#{ $new } == $#{ $old } && (
                    $new->[$i]->{data}->{day}   != $old->[$i]->{data}->{day}   ||
                    $new->[$i]->{data}->{month} != $old->[$i]->{data}->{month} ||
                    $new->[$i]->{data}->{year}  != $old->[$i]->{data}->{year}
                )) {
                $changed      = 1;
                $need_newdate = 0;
                last;
            }

        } elsif ($old && $#{ $new } == $#{ $old }) {
            my $n = join ':', %{ $new->[$i] };
            my $o = join ':', %{ $old->[$i] };
            if ($n ne $o) {
                $changed = 1;
            }
        } elsif ($#{ $new } != $#{ $old }) {
            $changed = 1;
        }
    }
    if ($old && (! @{ $old }) && $date_index) {
        $need_newdate = 0;
    }

    return 1, 0 if $changed == 0;

    if ($need_newdate || ! defined $date_index) {
        my ($day, $month, $year) = (localtime)[3,4,5];
        my $date = {
            year  => $year,
            month => $month,
            day   => $day,
        };
        if (defined $date_index) {
            $new->[$date_index]->{data} = $date;
        } else {
            push @{ $new }, {
                label => 'lastchange',
                font  => 0,
                data  => $date,
            };
        }
    } else {
        # XXX Need to actually validate the above information somehow
        if ($new->[$date_index]->{data}->{year} >= 1900) {
            $new->[$date_index]->{data}->{year} -= 1900;
        }
    }

    my $decrypted;
    foreach my $field (@{ $new }) {
        $decrypted .= _pack_field($field);
    }

    my $encrypted;
    if ($cipher_name eq 'None') {
        # do nothing
        $encrypted = $decrypted;

    } elsif ($cipher_name eq 'DES_EDE3' or $cipher_name eq 'Rijndael') {
        my $c = Crypt::CBC->new( 
            -literal_key => 1,
            -key         => $key,
            -iv          => $ivec,
            -cipher      => $cipher_name,
            -keysize     => $keylen,
            -header      => 'none',
            -padding     => 'oneandzeroes',
        );

        if (! $c) {
            croak("Unable to set up encryption!");
        }

        $encrypted = $c->encrypt($decrypted);

    } else {
        die "Unsupported Version";
    } 

    return $encrypted, $ivec;
}

# Decrypt

sub Decrypt
{
    my $self = shift;
    my $rec  = shift;
    my $pass = shift || $self->{password};

    if ( ! $pass && ! $self->{appinfo}->{key}) {
        croak("password not set!\n");
    }

    if ( ! $rec) {
        croak("Needed parameter 'record' not passed!\n");
    }

    if ( $pass && ! $self->Password($pass)) {
        croak("Invalid Password!\n");
    }

    if ( ! $rec->{encrypted} ) {
        croak("No encrypted content!");
    }

    if ($self->{version} == 4) {
        $self->{digest} ||= _calc_keys( $pass );
        my $acct = _decrypt_v4($rec->{encrypted}, $self->{digest});
        $acct->{name} ||= $rec->{name};
        return $acct;

    } elsif ($self->{version} == 5) {
        my $fields = _decrypt_v5(
            $rec->{encrypted}, $self->{appinfo}->{key}, 
            $self->{appinfo}->{cipher}, $rec->{ivec}, 
        );
        if ($self->{options}->{v4compatible}) {
            my %acct;
            foreach my $f (@{ $fields }) {
                $acct{ $f->{label} } = $f->{data};
            }
            $acct{name} ||= $rec->{name};
            return \%acct;
        } else {
            return $fields;
        }

    } else {
        die "Unsupported Version";
    }
    return;
}

sub _decrypt_v4
{
    my $encrypted = shift;
    my $digest    = shift;

    my $decrypted = _crypt3des( $encrypted, $digest, $DECRYPT );
    my ( $account, $password, $notes, $packed_date ) 
        = split /$NULL/xm, $decrypted, 4;

    my $modified;
    if ($packed_date) {
        $modified = _parse_keyring_date($packed_date);
    }

    return {
        account    => $account,
        password   => $password,
        notes      => $notes,
        lastchange => $modified,
    };
}

sub _decrypt_v5
{
    require Crypt::CBC;
    my $encrypted = shift;
    my $key       = shift;
    my $cipher    = shift;
    my $ivec      = shift;

    my $keylen       = $CRYPTS[ $cipher ]{keylen};
    my $cipher_name  = $CRYPTS[ $cipher ]{name};

    my $decrypted;

    if ($cipher_name eq 'None') {
        # do nothing
        $decrypted = $encrypted;

    } elsif ($cipher_name eq 'DES_EDE3' or $cipher_name eq 'Rijndael') {
        my $c = Crypt::CBC->new( 
            -literal_key => 1,
            -key         => $key,
            -iv          => $ivec,
            -cipher      => $cipher_name,
            -keysize     => $keylen,
            -header      => 'none',
            -padding     => 'oneandzeroes',
        );

        if (! $c) {
            croak("Unable to set up encryption!");
        }
        $encrypted .= $NULL x $keylen; # pad out a keylen
        $decrypted  = $c->decrypt($encrypted);

    } else {
        die "Unsupported Version";
        return;
    } 

    my @fields;
    while ($decrypted) {
        my $field;
        ($field, $decrypted) = _parse_field($decrypted);
        if (! $field) {
            last;
        }
        push @fields, $field;
    }

    return \@fields;
}

# Password

sub Password 
{
    my $self = shift;
    my $pass = shift;
    my $new_pass = shift;

    if (! $pass) {
        delete $self->{password};
        delete $self->{appinfo}->{key};
        return 1;
    }

    if (
        ($self->{version} == 4 && ! exists $self->{records}) ||
        ($self->{version} == 5 && ! exists $self->{appinfo}->{masterhash})
    ) {
        if ($self->{version} == 4) {
            # Give the PDB the first record that will hold the encrypted password
            $self->{records} = [ $self->new_Record ];
        }

        return $self->_password_update($pass);
    }

    if ($new_pass) {
        my $v4compat = $self->{options}->{v4compatible};
        $self->{options}->{v4compatible} = 0;

        my @accts = ();
        foreach my $i (0..$#{ $self->{records} }) {
            if ($self->{version} == 4 && $i == 0) {
                push @accts, undef;
                next;
            }
            my $acct = $self->Decrypt($self->{records}->[$i], $pass);
            if ( ! $acct ) {
                croak("Couldn't decrypt $self->{records}->[$i]->{name}");
            }
            push @accts, $acct;
        }

        if ( ! $self->_password_update($new_pass)) {
            croak("Couldn't set new password!");
        }
        $pass = $new_pass;

        foreach my $i (0..$#accts) {
            if ($self->{version} == 4 && $i == 0) {
                next;
            }
            delete $self->{records}->[$i]->{encrypted};
            $self->Encrypt($self->{records}->[$i], $accts[$i], $pass);
        }

        $self->{options}->{v4compatible} = $v4compat;
    }

    if (defined $self->{password} && $pass eq $self->{password}) {
        # already verified this password
        return 1;
    }

    if ($self->{version} == 4) {
        # AFAIK the thing we use to test the password is
        #     always in the first entry
        my $valid = _password_verify_v4($pass, $self->{records}->[0]->{data});

        # May as well generate the keys we need now, since we know the password is right
        if ($valid) {
            $self->{digest} = _calc_keys($pass);
            if ($self->{digest} ) {
                $self->{password} = $pass;
                return 1;
            }
        }
    } elsif ($self->{version} == 5) {
        return _password_verify_v5($pass, $self->{appinfo});
    } else {
        # XXX unsupported version
    }

    return;
}

sub _password_verify_v4 
{
    require Digest::MD5;
    import Digest::MD5 qw(md5);

    my $pass = shift;
    my $data = shift;

    if (! $pass) { croak('No password specified!'); };

    # XXX die "No encrypted password in file!" unless defined $data;
    if ( ! defined $data) { return; };

    $data =~ s/$NULL$//xm;

    my $salt = substr $data, 0, $kSalt_Size;

    my $msg = $salt . $pass; 
    $msg .= "\0" x ( $MD5_CBLOCK - length $msg );

    my $digest = md5($msg);

    if (! $data eq $salt . $digest ) {
        return;
    }

    return 1;
}

sub _password_verify_v5 
{
    my $pass    = shift;
    my $appinfo = shift;

    my $salt = pack("H*", $appinfo->{salt});

    my ($key, $hash) = _calc_key_v5(
        $pass, $salt, $appinfo->{iter}, 
        $CRYPTS[ $appinfo->{cipher} ]{keylen}, 
        $CRYPTS[ $appinfo->{cipher} ]{DES_odd_parity}, 
    );

    #print "Key:  '". unpack("H*", $key) . "'\n";
    #print "Hash: '". $hash . "'\n";
    #print "Hash: '". $appinfo->{masterhash} . "'\n";

    if ($appinfo->{masterhash} eq $hash) {
        $appinfo->{key} = $key;
    } else {
        return;
    }

    return $key;
}


sub _password_update 
{
    # It is very important to Encrypt after calling this
    #     (Although it is generally only called by Encrypt)
    # because otherwise the data will be out of sync with the
    # password, and that would suck!
    my $self   = shift;
    my $pass   = shift;

    if ($self->{version} == 4) {
        my $data = _password_update_v4($pass, @_);

        if (! $data) {
            carp("Failed  to update password!");
            return;
        }

        # AFAIK the thing we use to test the password is
        #     always in the first entry
        $self->{records}->[0]->{data} = $data;
        $self->{password} = $pass;
        $self->{digest}   = _calc_keys( $self->{password} );

        return 1;

    } elsif ($self->{version} == 5) {
        my $cipher  = shift || $self->{appinfo}->{cipher};
        my $iter    = shift || $self->{appinfo}->{iter};
        my $salt    = shift || 0;

        my $hash = _password_update_v5(
            $self->{appinfo}, $pass, $cipher, $iter, $salt
        );

        if (! $hash) {
            carp("Failed  to update password!");
            return;
        }

        return 1;
    } else {
        croak("Unsupported version ($self->{version})");
    }

    return;
}

sub _password_update_v4
{
    require Digest::MD5;
    import Digest::MD5 qw(md5);

    my $pass = shift;
    
    if (! defined $pass) { croak('No password specified!'); };

    my $salt;
    for ( 1 .. $kSalt_Size ) {
        $salt .= chr int rand 255;
    }

    my $msg = $salt . $pass;

    $msg .= "\0" x ( $MD5_CBLOCK - length $msg );

    my $digest = md5($msg);

    my $data = $salt . $digest;    # . "\0";

    return $data;
}

sub _password_update_v5
{
    my $appinfo = shift;
    my $pass    = shift;
    my $cipher  = shift;
    my $iter    = shift;

    # I thought this needed to be 'blocksize', but apparently not.
    #my $length  = $CRYPTS[ $cipher ]{blocksize};
    my $length  = 8;
    my $salt    = shift || pack("C*",map {rand(256)} 1..$length);

    my ($key, $hash) = _calc_key_v5(
        $pass, $salt, $iter, 
        $CRYPTS[ $cipher ]->{keylen}, 
        $CRYPTS[ $cipher ]->{DES_odd_parity},
    );

    $appinfo->{salt}           = unpack "H*", $salt;
    $appinfo->{iter}           = $iter;
    $appinfo->{cipher}         = $cipher;

    $appinfo->{key}            = $key;
    $appinfo->{masterhash}     = $hash;

    return $key;
}


sub _calc_keys 
{
    my $pass = shift;
    if (! defined $pass) { croak('No password defined!'); };

    my $digest = md5($pass);

    my ( $key1, $key2 ) = unpack 'a8a8', $digest;

    #--------------------------------------------------
    # print "key1: $key1: ", length $key1, "\n";
    # print "key2: $key2: ", length $key2, "\n";
    #--------------------------------------------------

    $digest = unpack 'H*', $key1 . $key2 . $key1;

    #--------------------------------------------------
    # print "Digest: ", $digest, "\n";
    # print length $digest, "\n";
    #--------------------------------------------------

    return $digest;
}

sub _calc_key_v5
{
    my ($pass, $salt, $iter, $keylen, $dop) = @_;

    require Digest::HMAC_SHA1;
    import  Digest::HMAC_SHA1 qw(hmac_sha1);
    require Digest::SHA1;
    import  Digest::SHA1 qw(sha1);

    my $key = _pbkdf2( $pass, $salt, $iter, $keylen, \&hmac_sha1 );
    if ($dop) { $key = DES_odd_parity($key); }

    my $hash = unpack("H*", substr(sha1($key.$salt),0, 8));

    return $key, $hash;
}

sub _crypt3des 
{
    require Crypt::DES;

    my ( $plaintext, $passphrase, $flag ) = @_;

    $passphrase   .= $SPACE x ( 16 * 3 );
    my $cyphertext = $EMPTY;

    my $size = length $plaintext;

    #print "STRING: '$plaintext' - Length: " . (length $plaintext) . "\n";

    my @C;
    for ( 0 .. 2 ) {
        $C[$_] =
          new Crypt::DES( pack 'H*', ( substr $passphrase, 16 * $_, 16 ));
    }

    for ( 0 .. ( ($size) / 8 ) ) {
        my $pt = substr $plaintext, $_ * 8, 8;

        #print "PT: '$pt' - Length: " . length($pt) . "\n";
        if (! length $pt) { next; };
        if ( (length $pt) < 8 ) {
            if ($flag == $DECRYPT) { croak('record not 8 byte padded'); };
            my $len = 8 - (length $pt);
            $pt .= ($NULL x $len);
        }
        if ( $flag == $ENCRYPT ) {
            $pt = $C[0]->encrypt($pt);
            $pt = $C[1]->decrypt($pt);
            $pt = $C[2]->encrypt($pt);
        }
        else {
            $pt = $C[0]->decrypt($pt);
            $pt = $C[1]->encrypt($pt);
            $pt = $C[2]->decrypt($pt);
        }

        #print "PT: '$pt' - Length: " . length($pt) . "\n";
        $cyphertext .= $pt;
    }

    $cyphertext =~ s/$NULL+$//xm;

    #print "CT: '$cyphertext' - Length: " . length($cyphertext) . "\n";

    return $cyphertext;
}

sub _parse_field 
{
    my $field = shift;

    my @labels;
    $labels[0]   = 'name';
    $labels[1]   = 'account';
    $labels[2]   = 'password';
    $labels[3]   = 'lastchange';
    $labels[255] = 'notes';

    my ($len) = unpack "S1", $field;
    if ($len + 4 > length $field) {
        return undef, $field;
    }
    my $unpackstr = "S1 C1 C1 A$len";
    if ($len % 2 && $len + 4 < length $field) {
        # trim the 0/1 byte padding for next even address.
        $unpackstr .= ' x' 
    }
    $unpackstr .= ' A*';

    my (undef, $label, $font, $data, $leftover) 
        = unpack $unpackstr, $field;

    if ($label == 3) {
        $data = _parse_keyring_date($data);
    }
    return {
        #len      => $len,
        label    => $labels[ $label ] || $label,
        label_id => $label,
        font     => $font,
        data     => $data,
    }, $leftover;
}

sub _pack_field 
{
    my $field = shift;

    my %labels = (
        name       =>   0,
        account    =>   1,
        password   =>   2,
        lastchange =>   3,
        notes      => 255,
    );

    my $label = $field->{label_id} || $labels{ $field->{label} };
    my $font  = $field->{font}     || 0;
    my $data  = $field->{data}     || '';

    if ($label == 3) {
        $data = _pack_keyring_date($data);
    }
    my $len = length $data;
    my $packstr = "S1 C1 C1 A*";

    my $packed = pack $packstr, ($len, $label, $font, $data);

    if ($len % 2) {
        # add byte padding for next even address.
        $packed .= $NULL;
    }

    return $packed;
}

sub _parse_keyring_date
{
    my $data = shift;

    my $u = unpack 'n', $data;
    my $year  = (($u & 0xFE00) >> 9) + 4; # since 1900
    my $month = (($u & 0x01E0) >> 5) - 1; # 0-11
    my $day   = (($u & 0x001F) >> 0);     # 1-31

    return {
        year   => $year,
        month  => $month || 0,
        day    => $day   || 1,
    };
}

sub _pack_keyring_date
{
    my $d = shift;
    my $year  = $d->{year};
    my $month = $d->{month};
    my $day   = $d->{day};

    $year -= 4;
    $month++;

    return pack 'n', $day | ($month << 5) | ($year << 9);
}


sub _hexdump
{
    my $prefix = shift;   # What to print in front of each line
    my $data = shift;     # The data to dump
    my $maxlines = shift; # Max # of lines to dump
    my $offset;           # Offset of current chunk

    for ($offset = 0; $offset < length($data); $offset += 16)
    {
        my $hex;   # Hex values of the data
        my $ascii; # ASCII values of the data
        my $chunk; # Current chunk of data

        last if defined($maxlines) && ($offset >= ($maxlines * 16));

        $chunk = substr($data, $offset, 16);

        ($hex = $chunk) =~ s/./sprintf "%02x ", ord($&)/ges;

        ($ascii = $chunk) =~ y/\040-\176/./c;

        printf "%s %-48s|%-16s|\n", $prefix, $hex, $ascii;
    }
}

sub _bindump
{
    my $prefix = shift;   # What to print in front of each line
    my $data = shift;     # The data to dump
    my $maxlines = shift; # Max # of lines to dump
    my $offset;           # Offset of current chunk

    for ($offset = 0; $offset < length($data); $offset += 8)
    {
        my $bin;   # binary values of the data
        my $ascii; # ASCII values of the data
        my $chunk; # Current chunk of data

        last if defined($maxlines) && ($offset >= ($maxlines * 8));

        $chunk = substr($data, $offset, 8);

        ($bin = $chunk) =~ s/./sprintf "%08b ", ord($&)/ges;

        ($ascii = $chunk) =~ y/\040-\176/./c;

        printf "%s %-72s|%-8s|\n", $prefix, $bin, $ascii;
    }
}

# Thanks to Jochen Hoenicke <hoenicke@gmail.com> 
# (one of the authors of Palm Keyring)
# for these next two subs.

# Usage pbkdf2(password, salt, iter, keylen, prf)
# iter is number of iterations
# keylen is length of generated key in bytes
# prf is the pseudo random function (e.g. hmac_sha1)
# returns the key.
sub _pbkdf2($$$$$)
{
    my ($password, $salt, $iter, $keylen, $prf) = @_;
    my ($k, $t, $u, $ui, $i);
    $t = "";
    for ($k = 1; length($t) <  $keylen; $k++) {
    $u = $ui = &$prf($salt.pack('N', $k), $password);
    for ($i = 1; $i < $iter; $i++) {
        $ui = &$prf($ui, $password);
        $u ^= $ui;
    }
    $t .= $u;
    }
    return substr($t, 0, $keylen);
}

sub DES_odd_parity($) {
    my $key = $_[0];
    my ($r, $i);
    my @odd_parity = (
  1,  1,  2,  2,  4,  4,  7,  7,  8,  8, 11, 11, 13, 13, 14, 14,
 16, 16, 19, 19, 21, 21, 22, 22, 25, 25, 26, 26, 28, 28, 31, 31,
 32, 32, 35, 35, 37, 37, 38, 38, 41, 41, 42, 42, 44, 44, 47, 47,
 49, 49, 50, 50, 52, 52, 55, 55, 56, 56, 59, 59, 61, 61, 62, 62,
 64, 64, 67, 67, 69, 69, 70, 70, 73, 73, 74, 74, 76, 76, 79, 79,
 81, 81, 82, 82, 84, 84, 87, 87, 88, 88, 91, 91, 93, 93, 94, 94,
 97, 97, 98, 98,100,100,103,103,104,104,107,107,109,109,110,110,
112,112,115,115,117,117,118,118,121,121,122,122,124,124,127,127,
128,128,131,131,133,133,134,134,137,137,138,138,140,140,143,143,
145,145,146,146,148,148,151,151,152,152,155,155,157,157,158,158,
161,161,162,162,164,164,167,167,168,168,171,171,173,173,174,174,
176,176,179,179,181,181,182,182,185,185,186,186,188,188,191,191,
193,193,194,194,196,196,199,199,200,200,203,203,205,205,206,206,
208,208,211,211,213,213,214,214,217,217,218,218,220,220,223,223,
224,224,227,227,229,229,230,230,233,233,234,234,236,236,239,239,
241,241,242,242,244,244,247,247,248,248,251,251,253,253,254,254);
    for ($i = 0; $i< length($key); $i++) {
    $r .= chr($odd_parity[ord(substr($key, $i, 1))]);
    }
    return $r;
}

1;
__END__
=head1 NAME

Palm::Keyring - Handler for Palm Keyring databases.

=head1 DESCRIPTION

The Keyring PDB handler is a helper class for the Palm::PDB package. It
parses Keyring for Palm OS databases.  See
L<http://gnukeyring.sourceforge.net/>.

It has the standard Palm::PDB methods with 2 additional public methods.  
Decrypt and Encrypt.

It currently supports the v4 Keyring databases.  
The pre-release v5 databases are mostly supported.  There are definitely some 
bugs,  For example, t/keyring5.t sometimes fails.  I am not sure why yet.

This module doesn't store the decrypted content.  It only keeps it until it 
returns it to you or encrypts it.

=head1 SYNOPSIS

    use Palm::PDB;
    use Palm::Keyring;
    
    my $pass = 'password';
    my $file = 'Keys-Gtkr.pdb';
    my $pdb  = new Palm::PDB;
    $pdb->Load($file);
    
    foreach (0..$#{ $pdb->{records} }) {
        # skip the password record for version 4 databases
        next if $_ == 0 && $pdb->{version} == 4;
        my $rec  = $pdb->{records}->[$_];
        my $acct = $pdb->Decrypt($rec, $pass);
        print $rec->{name}, ' - ', $acct->{account}, "\n";
    }

=head1 SUBROUTINES/METHODS

=head2 new

    $pdb = new Palm::Keyring([$password[, $version]]);

Create a new PDB, initialized with the various Palm::Keyring fields
and an empty record list.

Use this method if you're creating a Keyring PDB from scratch otherwise you 
can just use Palm::PDB::new() before calling Load().

If you pass in a password, it will initalize the first record with the encrypted 
password.

new() now also takes options in other formats

    $pdb = new Palm::Keyring({ key1 => value1,  key2 => value2 });
    $pdb = new Palm::Keyring( -key1 => value1, -key2 => value2);

=head3 Supported options are:

=over

=item password

The password used to initialize the database

=item version

The version of database to create.  Accepts either 4 or 5.  Currently defaults to 4.

=item v4compatible

The format of the fields passed to Encrypt and returned from Decrypt have changed.
This allows programs to use the newer databases with few changes but with less features.

=item cipher

The cipher to use.  0, 1, 2 or 3.  

    0 => None
    1 => DES_EDE3
    2 => AES128
    3 => AES256

=item iterations

The number of iterations to encrypt with.

=back

=head2 Encrypt

    $pdb->Encrypt($rec, $acct[, $password]);

Encrypts an account into a record, either with the password previously 
used, or with a password that is passed.

$rec is a record from $pdb->{records} or a new_Record().
The v4 $acct is a hashref in the format below.

    my $v4acct = {
        name       => $rec->{name},
        account    => $account,
        password   => $password,
        notes      => $notes,
        lastchange => {
            year  => 107, # years since 1900
            month =>   0, # 0-11, 0 = January, 11 = December
            day   =>  30, # 1-31, same as localtime
        },
    };

The v5 $acct is an arrayref full of hashrefs that contain each encrypted field.

    my $v5acct = [
        {
            'label_id' => 2,
            'data' => 'abcd1234',
            'label' => 'password',
            'font' => 0
        },
        {
            'label_id' => 3,
            'data' => {
                'month' => 1,
                'day' => 11,
                'year' => 107
            },
            'label' => 'lastchange',
            'font' => 0
        },
        {
            'label_id' => 255,
            'data' => 'This is a short note.',
            'label' => 'notes',
            'font' => 0
        }
    ];


The account name is stored in $rec->{name} for both v4 and v5 databases.  
It is not returned in the decrypted information for v5.

    $rec->{name} = 'account name';

If you have changed anything other than the lastchange, or don't pass in a 
lastchange key, Encrypt() will generate a new lastchange date for you.

If you pass in a lastchange field that is different than the one in the
record, it will honor what you passed in.

Encrypt() only uses the $acct->{name} if there is not already a $rec->{name}.

=head2 Decrypt

    my $acct = $pdb->Decrypt($rec[, $password]);

Decrypts the record and returns a reference for the account as described 
under Encrypt().  

    foreach (0..$#{ $pdb->{records}) {
        next if $_ == 0 && $pdb->{version} == 4;
        my $rec = $pdb->{records}->[$_];
        my $acct = $pdb->Decrypt($rec);
        # do something with $acct
    }


=head2 Password

    $pdb->Password([$password[, $new_password]]);

Either sets the password to be used to crypt, or if you pass $new_password, 
changes the password on the database.

If you have created a new $pdb, and you didn't set a password when you 
called new(), you only need to pass one password and it will set that as 
the password. 

If nothing is passed, it forgets the password that it was remembering.

=head1 DEPENDENCIES

Palm::StdAppInfo

Digest::MD5

Crypt::DES

Readonly

=head1 THANKS

I would like to thank the helpful Perlmonk shigetsu who gave me some great advice
and helped me get my first module posted.  L<http://perlmonks.org/?node_id=596998>

I would also like to thank 
Johan Vromans
E<lt>jvromans@squirrel.nlE<gt> -- 
L<http://www.squirrel.nl/people/jvromans>.
He had his own Palm::KeyRing module that he posted a couple of days before 
mine was ready and he was kind enough to let me have the namespace as well 
as giving me some very helpful hints about doing a few things that I was 
unsure of.  He is really great.

=head1 BUGS AND LIMITATIONS

Please report any bugs or feature requests to
C<bug-palm-keyring at rt.cpan.org>, or through the web interface at
L<http://rt.cpan.org>.  I will be notified, and then you'll automatically be
notified of progress on your bug as I make changes.

=head1 AUTHOR

Andrew Fresh E<lt>andrew@cpan.orgE<gt>

=head1 LICENSE AND COPYRIGHT

Copyright 2004, 2005, 2006, 2007 Andrew Fresh, All Rights Reserved.

This program is free software; you can redistribute it and/or 
modify it under the same terms as Perl itself.

=head1 SEE ALSO

Palm::PDB(3)

Palm::StdAppInfo(3)

The Keyring for Palm OS website: 
L<http://gnukeyring.sourceforge.net/>

The HACKING guide for palm keyring databases:
L<http://gnukeyring.cvs.sourceforge.net/*checkout*/gnukeyring/keyring/HACKING>

Johan Vromans also has a wxkeyring app that now uses this module, available 
from his website at L<http://www.vromans.org/johan/software/sw_palmkeyring.html>