compression - How does hiding files in jpeg file works -


i reading article explaining how hide files in jpeg pictures.

i wondering how it's possible file contain both jpeg data , rar file without visible distortion either image or compressed file.

my guess has how either compressed file or jpeg file represented in binary form, have no idea how works.

can elaborate on that?

all doing adding archive end of jpeg stream. hope jpeg decoder not read past eoi marker, find data there, , wrong.

a jpeg image stream of bytes starting soi marker , ending eoi marker.

zip , rar streams of byte. zip stream starts 50 4b. rar stream starts 52 61 72 21 1a 07.

the method described in link above takes binary copy of (multiple) jpeg stream , appends zip or rar stream it.

the rar/zip decoders scan stream until find signature rar or zip (ignoring jpeg stream).


-

Comments

Post a Comment

Popular posts from this blog

css - SVG using textPath a symbol not rendering in Firefox -

using textpath within symbol doesn't render in firefox. renders fine in latest chrome , ie, when try reference symbol, svg text doesn't render in firefox (37.0.1) - first box appears empty. code below (no external dependencies), there should 2 boxes word test flowing vertically in centre of each. edit: thought issue somehow involved flexbox layout, until paul pointed out issue exists without flexbox layout. the html is: <div> <svg id="not_working" viewbox="0 0 250 1200" preserveaspectratio="xmidymid meet"> <symbol id="test_symbol1" preserveaspectratio="xmidymid meet" viewbox="0 0 250 1200"> <path id="test_symbol_path" d="m 100 1200 l 100 0" /> <text font-size="100" fill="red"> <textpath text-anchor="middle" startoffset="50%" xlink:href="#test_symbol_path...
Read more

Java 8 + Maven Javadoc plugin: Error fetching URL -

i attempting generate javadoc links javadoc dependencies. have tried various means generate javadoc not produce qualified class names references classes dependencies. wanted links java doc simplified class names. however, java api classnames, no links , have qualified class names. working java 8. have following configuration: <plugin> <groupid>org.apache.maven.plugins</groupid> <artifactid>maven-javadoc-plugin</artifactid> <version>2.10.2</version> <configuration> <reportoutputdirectory>${project.basedir}/target</reportoutputdirectory> <destdir>javadoc</destdir> <windowtitle>epiphany</windowtitle> <doctitle>epiphany</doctitle> <show>private</show> <detectlinks>false</detectlinks> <detectoffline...
Read more

order - Notification for user in user account opencart -

thanks helps or points me in right direction. i want show pending notification user in account page after login. notification show when order status pending. after changing other status admin remove notification. this notification show like: your order id: order status: , [ button custom url] if multiple order show multiple order id. open cart version 1.5.6.3 custom theme. $this->load->model('account/order'); $results = $this->model_account_order->getorders(); foreach ($results $result) { $product_total = $this->model_account_order->gettotalorderproductsbyorderid($result['order_id']); $voucher_total = $this->model_account_order->gettotalordervouchersbyorderid($result['order_id']); if( $result['status'] =! 5){ // 5 order status means completed $this->data['orders'][] = array( 'order_id' => $result['order_id'], ...
Read more