Drmcomp.exe

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Ian
New member
Username: Efhatch

Post Number: 1
Registered: 06-2006
Posted on Wednesday, June 14, 2006 - 01:59 am:   

Hi,

I have a question. I try using the command line drmcomp.exe which is included in the NowSMS software.

I create a .dm file for jpg, .3gp, etc.

I try copying it to Ericsson and Nokia Phone.

Files can be viewed in the Ericsson and forward locking is also working.

But in Nokia N70 the file cannot be viewed and an error is showing up. "Unknown File Format". what could possible be wrong?

Also do you have an updated drmcomp.exe that is now OMA DRM 2.0 compatible?

Hope for your kind responses.

More Power!

Sincerely,
IANIAN
Ian
New member
Username: Efhatch

Post Number: 2
Registered: 06-2006
Posted on Wednesday, June 14, 2006 - 03:01 am:   

by the way i transfer this files through data cable. would it be alright If i transfer files through data cable?
Ian
New member
Username: Efhatch

Post Number: 3
Registered: 06-2006
Posted on Wednesday, June 14, 2006 - 03:10 am:   

I am also using the lates version of DRMCOMP.exe which is date March 14, 2006.
Ian
New member
Username: Efhatch

Post Number: 4
Registered: 06-2006
Posted on Wednesday, June 14, 2006 - 03:45 am:   

Forwardlocking is working in ericsson but combineddelivery and separate delivery is not.

Did I miss something on the process?

I use drmcomp.exe and transfer the file to the mobile phone through data cable.
Bryce Norwood - NowSMS Support
Board Administrator
Username: Bryce

Post Number: 6034
Registered: 10-2002
Posted on Wednesday, June 14, 2006 - 09:33 pm:   

Ian,

I don't have any experience in manually copying the files to a phone.

I always transfer them to the phone via either MMS, or download with the internet browser.

One reason for this is because when a file is transferred via either MMS or a browser download, there is a MIME type associated with the object. In the case of a "forward lock" or "combined delivery", it is "application/vnd.oma.drm.message". In the case of "separate delivery" it is "application/vnd.oma.drm.content".

However, when you just copy a file over, there is no MIME type associated with it. The phone might perform some file extension to MIME type mapping. But then again, it might not.

Like I said, I don't have experience with just copying the files over, so I can't really offer any further comment.

There is not an OMA DRM v2.0 compliant version of DRMCOMP available, only 1.0.

-bn
Ian
New member
Username: Efhatch

Post Number: 5
Registered: 06-2006
Posted on Thursday, June 15, 2006 - 01:42 am:   

the drmcomp.exe puts the mime type "application/vnd.oma.drm.message" or "application/vnd.oma.drm.content" in the header of the file right? So I think there is already a mime type association even copy by phone.

By the way what does this mime type means? I mean where are they files need by phone and where does this mime type came from?

Please bare with me, as I am new to this technology.

Also can an ordinary web server can be used as a wap server? I mean If I directly put the link of the .dm file can the phone recognize it when it is downloaded?

Also can you please give me an example on how to setup a separate delivery drm on the web server and how it will be downloaded correctly by phone?

Thank You So Much.
Bryce Norwood - NowSMS Support
Board Administrator
Username: Bryce

Post Number: 6042
Registered: 10-2002
Posted on Thursday, June 15, 2006 - 10:54 pm:   


quote:

the drmcomp.exe puts the mime type "application/vnd.oma.drm.message" or "application/vnd.oma.drm.content" in the header of the file right? So I think there is already a mime type association even copy by phone.




No. It cannot do this.

It's not a DRM or DRMCOMP issue ... it's more of an issue that a MIME type is an external attribute to a file ... not a part of the file content itself.

Let's take a JPEG image file for example. The MIME content type identifier for this type of file is "image/jpeg". And by convention, JPEG files have a file extension (i.e., the part after the "." in a file name) of ".jpg" or ".jpeg".

So it is pretty standard behaviour that if you put a file with a ".jpg" or ".jpeg" extension onto a phone, the phone will automatically recognise that this is a JPEG file.

File extension to content type mapping works well for the common file types ... this is how Windows decides what application to launch when you click on a particular file ... but a lot of content types aren't so well known.

When you download a file via a browser, there is a header in the file download that provides the MIME content type associated with the file ... independent of any file extension. This is how the browser determines the content type and how to process the received file.

In Windows, it's easy to add a file extension to content type mapping.

But it's a different story on a mobile device.

My point was basically that if a phone supports DRM content types, it is expecting to receive them via the browser interface or MMS. And the developers of the phone software might not have expected that files would just be copied to the phone ... so they might not have file extension to content type mappings for the DRM content types.


quote:

Also can an ordinary web server can be used as a wap server? I mean If I directly put the link of the .dm file can the phone recognize it when it is downloaded?




Yes.

It is easy to get confused because people sometimes talk about "WAP Servers" as being a separate entity. That is because in a WAP environment, there is generally a WAP gateway (or WAP proxy is another terminology) that sits between the phone and the web server that hosts the actual content.

But there is generally no reason for you to be concerned with a WAP gateway or WAP proxy ... as an end user, you would simply be using whatever one is installed at your mobile operator ... and that is transparent to you.

The actual content server is a standard web server. The only catch is that MIME content types are important for browsers. So you need to configure your web server to map the DRM file extensions to the appropriate MIME content type ... such as:

.dm=application/vnd.oma.drm.message
.dcf=application/vnd.oma.drm.content

How you configure this varies by web server, but it's generally an easy process.

There is a separate delivery example here:

http://support.nowsms.com/discus/messages/485/14341.html

... but note that the "rights issuer" URL referenced in the example is not currently functional. The rights object must be delivered via SMS ... and the script has been disabled so that it will not send the actual SMS (sorry, but too many people were trying to abuse the script). But basically, all the script does is send the rights object referenced in the ZIP example.

-bn


Ian
New member
Username: Efhatch

Post Number: 6
Registered: 06-2006
Posted on Friday, June 16, 2006 - 02:36 am:   

Thank You So Much. =)
Now I am having a good idea on how this works.

Now another question,
So in OMA Download with Forwardlocking, If I download a file then I would not be able to send the file right?

Now the Scenario:

Assuming that the image file in my Phone1 cannot be sent through bluetooth, etc.
What If I copy that image file from Phone1 to my PC through data cable and then copy it to Phone2 through a data cable also.
I think the file can now be forwarded by Phone2 to any phone, am I right?

So you mean that OMA Forwardlocking is not that secure and the most secure way is through separate delivery?