When Blocked Caller ID Calls Are Not Really Blocked

You may think turning off, or blocking, your caller ID can make you anonymous to the person you are calling. Well...... it can but..... not really. Linda Scott out at the Education Development Center in Newton, MA paased along a link to a service called Trapcall. This service can be used to unmask blocked and restricted calls, allow users to blacklist harassing callers, and can also record incoming calls. There is no software to install and the service will work on mobile phones from AT&T, Verizon, T-Mobile and Sprint.

Here’s a piece on how TrapCall works from a 2009 Wired article:

TrapCall takes advantage of a loophole in Caller ID blocking that’s long benefited corporate phone customers: Namely, calls to toll-free numbers are not blocked, because those calls are paid for by the recipient.

TrapCall instructs new customers to reprogram their cellphones to send all rejected, missed and unanswered calls to TrapCall’s own toll-free number. If the user sees an incoming call with Caller ID blocked, he just presses the button on the phone that would normally send it to voicemail. The call invisibly loops through TelTech’s system, then back to the user’s phone, this time with the caller’s number displayed as the Caller ID.

The caller hears only ringing during this rerouting, which took about six seconds in Wired.com’s test with an iPhone on AT&T. Rejecting the call a second time, or failing to answer it, sends it to the user’s standard voicemail.

And, here’s a short video from HousholdHacker demonstrating the service:

If you think this stuff is not very popular take a look at the YouTube view counter for the video - almost 2.4 million views as of today.

In my 2003 book Introduction to Telecommunications Networks I wrote the constitutionality of caller ID has been repeatedly challenged in court with people having three major concerns:

• The right to be left alone
• The right to be free from unreasonable searches or seizures
• And, the right to not be subjected to unreasonable government intrusions

Privacy works both ways for me. I don’t think I’ve got much to hide so don’t worry too much about having to block my caller ID. If I do have concerns about my number getting out I’ll just use another phone with a public number. If someone does call me from a blocked number, I typically just let it go to voicemail.

Traffic Shaping: BitTorrent and P2PTV

Lately there's been a lot of press about Internet Service Provider (ISP) traffic shaping with much of the discussion focused on BitTorrent based applications. Let's take a look at BitTorrent and how it is being used to distribute large files on the Internet. I'll use content from a Free Press piece published last fall to describe the steps involved for a user to start using BitTorrent:

Step 1: A user first downloads a program known as a BitTorrent client. Popular bit torrent clients (there are many) include uTorrent, BitComet and ABC. Once a BitTorrent client is installed the user can then share and download files.

Step 2: Once the client is installed, users can then search for interesting content. The user then finds a “torrent,” which is a miniscule file that serves to point a user’s computer in the direction of that file’s location. The torrent contains data that identify the file or files to be downloaded and a tracker notifying the computer coordinating such file distribution (many also utilize a trackerless system in which each connected computer acts as a tracker) that another user is interested in obtaining the file. All the rest of the BitTorrent users currently downloading or possessing the file (through keeping their application open, known as “seeding”) help transmit small portions of the overall file to the requesting user.

Step 3: As the user begins to acquire portions of the overall file, their computer redistributes the content to other users also requesting the file. The BitTorrent protocol differs from traditional point to point P2P networks where a central server distributes the information to each user, thereby putting all the strain on a single source.

Since it was released in 2001, BitTorrent has been the focus of some bad press because it can be used to illegally distribute copyrighted content. Things are changing though - BitTorrent applications also allow original content creators to not incur the entire cost of hardware, hosting and bandwidth - potentially providing huge savings to networks selling video content, record companies selling music, companies selling software.

One of my favorite BitTorrent "like" applications is Joost. Joost uses Peer-to-Peer television (P2PTV) to legally distribute content. We've all watched video streams (YouTube is a good example) where the video is streamed off a server - nice but relatively low resolution. Joost (requires an install of a separate application and does not run in a web browser) uses P2PTV to deliver high resolution video by having each client running it propagate the stream to more downstream clients. This moves the distribution costs from the channel owner to the user.

Later this week I'll write about technology that can be used to shape this kind of traffic on a network.