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lib/Captcha/Stateless/Text.pm  view on Meta::CPAN

    key => 'tyDjb39dQ20pdva0lTpyuiowWfxSSwa9', # 32 bytes / 256 bits (AES256)
    ep_pre => 'captcha'.lc(substr(md5_hex(__PACKAGE__), 0, 6)).'.',
  };
  bless $self, $class;
  return $self;
}

#############################################################################
# Object parameter get/set functions ########################################
#############################################################################
sub get_ep_pre($self)           { return $self->{ep_pre}; }
sub set_self_val($self, $k, $v) { $self->{$k} = $v; }
sub set_cipher($self, $v)       { set_self_val($self, 'cipher', $v); }
sub set_iv($self, $v)           { set_self_val($self, 'iv', $v); }
sub set_key($self, $v)          { set_self_val($self, 'key', $v); }

#############################################################################
# Crypto functions ##########################################################
#############################################################################
sub encrypt_b64($self, $data) {
  my $d = my_crypt_cbc($self, 'encrypt', $self->{cipher}, $self->{key}, $self->{iv}, $data);
  return MIME::Base64::encode_base64url($d, ''); # '' for no line breaks
}
sub decrypt_b64($self, $data) {
  my $d = MIME::Base64::decode_base64url($data);
  return my_crypt_cbc($self, 'decrypt', $self->{cipher}, $self->{key}, $self->{iv}, $d);
}
# Helper function to centralize and reduce code duplication
sub my_crypt_cbc($self, $mode, $cipher, $key, $iv, $data) {
  my $pkg = __PACKAGE__;

  my $cbc = Crypt::Mode::CBC->new($cipher, 1);
  if ($mode eq 'encrypt') {
    my $payload = undef;
    try {
      $payload = $cbc->encrypt($data, $key, $iv); # ENCRYPT
    } catch {
      warn("$pkg my_crypt_cbc() failed to $mode with error: $_");
      $payload = undef;

lib/Captcha/Stateless/Text.pm  view on Meta::CPAN

sub getQA_chars {
  my $qa = $QAfuncs{chars}(@_);
  $_[0]->add_enc_payload($qa);
  return $qa;
}
sub getQA_math {
  my $qa = $QAfuncs{math}(@_);
  $_[0]->add_enc_payload($qa);
  return $qa;
}
sub add_enc_payload($self, $qa) {
  # Make and add the enc_payload
  my $payload_json = to_json($qa);
  my $enc_payload = $self->encrypt_b64($payload_json);
  $qa->{enc_payload} = $self->{ep_pre} . $enc_payload;
}
sub validate($self, $answer, $enc_payload) {
  my $ep_pre = $self->{ep_pre};
  return 0 if (!(defined($enc_payload) && length($enc_payload)));
  return 0 if ($enc_payload !~ m/^\Q$ep_pre\E/); # Invalid payload
  $enc_payload =~ s/^\Q$ep_pre\E//; # Trim the prefix
  my $payload = $self->decrypt_b64($enc_payload);
  return 0 if (!defined($payload));
  my $qa = from_json($payload);
  return 1 if ($qa->{a} =~ m/^\d+$/ && $answer == $qa->{a});
  return 1 if ($answer eq $qa->{a});
  return 0;