Monday, March 12, 2007

Here is my program, sign it yourself!

I've bumped into the following blog today. This is exactly what I was thinking about a few weeks ago! I asked myself if developers could distribute their apps freely? Of course, the bottleneck is that they have to sign their apps properly, which is time-consuming and costly. But if one publishes his unsigned SIS file (it can be signed as well, since a file can be re-signed), then it can be freely signed by anybody else. So that the author can get rid of the burden of having to have his application SymbianSigned before distribution takes place.

One issue, though, that this workaround raises is trust. Why would I sign a SIS if it's from somebody whom I don't know? Why would I trust the program and presume that it will make no damage, generate extra cost, etc.? Of course, it's such an issue that must be carefully considered, case by case, program by program. But still there are programs whose authors are well-known and respected: they haven't all had time/money to bother with signing. Or let's take open source projects: unless they have good funding they will never spend money on content signing, which cost will never be returned. Not as if I was aware of such an open source project, but still. :)

So let's have a closer look at how it would work in practice! The classification of capabilities is as follows:
Group #1: User-grantable capabilities that can be granted by the user upon installation.
Capabilities: LocalServices, UserEnvironment, NetworkServices, Location, ReadUserData and WriteUserData.

Group #2: Powerful capabilities that cannot be granted by the user, but do not require any manufacturers' approval.
Capabilities: PowerMgmt, ReadDeviceData, WriteDeviceData, TrustedUI, ProtServ, SwEvent, SurroundingsDD.

Group #3: The most sensitive capabilities that only device manufacturers (i.e. not SymbianSigned or any other authority) can grant.
Capabilities: AllFiles, CommDD, DiskAdmin, MultimediaDD, NetworkControl, TCB, DRM.

If one writes a program that requires capabilities from groups #1-2 then it can be easily signed by anybody even if it demands some sort of technical mindedness. The steps for being able to install such a SIS file on our phone are as follows:

  • Registration on SymbianSigned.com.
  • Requesting a developer certificate for a given IMEI (i.e. the person's own mobile phone).
  • Once having the DevCert, sign the program with it.
Following these steps enables anyone to sign any (Symbian) programs that can eventually be installed on a (Symbian) smartphone. On any programs, I meant those that do not require capabilities from the third group. Another constraint of a single DevCert is the inability to sign a program for more than one phone. That requires an ACS Publisher ID from VeriSign - costs 350 bucks, btw.

And what about those programs that use APIs protected by capabilities from group #3? For them, one must have an ACS Publisher ID even for a single phone. And not only is it the cost that might prevent most people from requesting a publisher ID from VeriSign. If you'd like to be able to sign programs with the most sensitive capabilities, then getting a publisher ID is the easier task. The second step is to issue a request to the device manufacturer in which you detail which capability you need and why. On API level (e.g. I need RFormat::Open() to use and for that I have to have DiskAdmin capability) and for each capability one by one. And believe me it's tough! It's time and energy consuming and sometimes doesn't lack unnecessary conversation with the manufacturer ('we don't think you need that capability' ... arghh).

As a brief summary I still think that it's worth going on this path. For a well-isolated target group, namely mobile geeks, but for them it's really worth. Yes, it's you who reads this blog. :)

Migrated from Forum Nokia Blogs.

Tote

3 comments:

Anonymous said...

Can you help me register with Symbian Signed, it keeps saying that I need a private email domain, do you know a solution around this?

could you please reply to irbedgman@gmail.com

Gerard Lim said...

Hello Gábor Török

I am in the exact spot you were in: I need RFormat in DiskAdmin Capability. May I ask how or what was the procedure you took to obtain the Manufacturer's permission for that Capability?

Thanks.

Gábor Török said...

Hi,

First off, Symbian Signed has changed recently resulting in that IF you have a developer certificate (which requires a Publisher ID), then you don't have to ask for permission from any manufacturers in order to use this capability. For TESTING.

Having your program signed, though, it's a different issue: I presume you do need to contact the device manufacturer in question (Nokia, Sony Ericsson, etc.) and there must be a template available on SymbianSigned.com for this purpose. You've got to fill out that template, in which you must explain what you need and why - it'll be up to the device manufacturer to decide if they grant it to you or not.