1 files changed, 87 insertions, 0 deletions
diff --git a/lib/Spreadsheet/ParseXLSX/Decryptor/Standard.pm b/lib/Spreadsheet/ParseXLSX/Decryptor/Standard.pm
new file mode 100644
index 0000000..a940719
--- /dev/null
+++ b/lib/Spreadsheet/ParseXLSX/Decryptor/Standard.pm
@@ -0,0 +1,87 @@
+package Spreadsheet::ParseXLSX::Decryptor::Standard;
+use strict;
+use warnings;
+
+use base 'Spreadsheet::ParseXLSX::Decryptor';
+
+sub new {
+    my $class = shift;
+    my $self = Spreadsheet::ParseXLSX::Decryptor->new(@_);
+    bless $self, $class;
+}
+
+sub decrypt {
+    my $self = shift;
+    my ($encryptedValue) = @_;
+
+    my $key = $self->_generateDecryptionKey("\x00" x 4);
+    my $ecb = Crypt::Mode::ECB->new($self->{cipherAlgorithm}, 0);
+    return $ecb->decrypt($encryptedValue, $key);
+}
+
+sub decryptFile {
+    my $self = shift;
+    my ($inFile, $outFile, $bufferLength, $fileSize) = @_;
+
+    my $key = $self->_generateDecryptionKey("\x00" x 4);
+    my $ecb = Crypt::Mode::ECB->new($self->{cipherAlgorithm}, 0);
+
+    my $inbuf;
+    my $i = 0;
+
+    while (($fileSize > 0) && (my $inlen = $inFile->read($inbuf, $bufferLength))) {
+        if ($inlen < $bufferLength) {
+            $inbuf .= "\x00" x ($bufferLength - $inlen);
+        }
+
+        my $outbuf = $ecb->decrypt($inbuf, $key);
+        if ($fileSize < $inlen) {
+            $inlen = $fileSize;
+        }
+
+        $outFile->write($outbuf, $inlen);
+        $i++;
+        $fileSize -= $inlen;
+    }
+}
+
+sub _generateDecryptionKey {
+    my $self = shift;
+    my ($blockKey) = @_;
+
+    my $hash;
+    unless ($self->{pregeneratedKey}) {
+        $hash = $self->{hashProc}->($self->{salt} . Encode::encode('UTF-16LE', $self->{password}));
+        for (my $i = 0; $i < $self->{spinCount}; $i++) {
+            $hash = $self->{hashProc}->(pack('L', $i) . $hash);
+        }
+        $self->{pregeneratedKey} = $hash;
+    }
+
+    $hash = $self->{hashProc}->($self->{pregeneratedKey} . $blockKey);
+
+    my $x1 = $self->{hashProc}->(("\x36" x 64) ^ $hash);
+    if (length($x1) >= $self->{keyLength}) {
+        $hash = substr($x1, 0, $self->{keyLength});
+    } else {
+        my $x2 = $self->{hashProc}->(("\x5C" x 64) ^ $hash);
+        $hash = substr($x1 . $x2, 0, $self->{keyLength});
+    }
+
+    return $hash;
+}
+
+sub verifyPassword {
+    my $self = shift;
+
+    my ($encryptedVerifier, $encryptedVerifierHash) = @_;
+
+    my $verifier = $self->decrypt($encryptedVerifier);
+    my $verifierHash = $self->decrypt($encryptedVerifierHash);
+
+    my $verifierHash0 = $self->{hashProc}->($verifier);
+
+    die "Wrong password: $self" unless ($verifierHash0 eq substr($verifierHash, 0, length($verifierHash0)));
+}
+
+1;