Database Develop

[DEV] Blackstone Linux / Android Development

This thread is for development discussion only. If you are not actively working on the project, please go to the discussion thread where your contribution will be more valuable. By keeping this thread clean, we can hope to get Android working on our devices much quicker.​
Project Status:
We now have a 2.6.27 kernel which is capable of booting Angstrom and Android. Android looks good and is responsive, but most core functions are not there yet. Work is focused on kernel development to provide us with a stable base with working hardware. You can find test files in the second post.
We have a Wiki page where the project gets documented in some detail.
History
The development had a slow start while Orux worked out how to make the mdp talk to mddi to get a working display. We hope that progress will be faster now as there has been considerable work on the Diamond and Raphael hardware, which is quite similar to the Blackstone.
23Feb09
Screen problems fixed at last - many weeks work from Orux got the mdp talking to mddi and give us a working display.
03Mar09
Wow! So much progress in just a week! We now have working SD (some issues with brands of cards - under investigation), allowing booting direct from the SD card; working hardware buttons, and some GSM functionality (the network connects and reports of sending SMS successfully). Credit to Orux, Pichurri, Cybersalsero, Jonlar (and have I missed anyone out - not me, I have been spectating!). Pichurri has posted a full install package on teh wiki, go try it and give feedback in the testing thread.
(to be continued!)
Current tasks
Debugging SD card problems many ppl having
Getting our own version of Android (currently using builds optimised for Raph/Diam
More GSM functions - who will be first to make a call???
What can I do?
You tell us! First thing would be to get yourself set up with a development environment. You need Linux on your PC - either installed as the main OS or if you use Windows, in a virtual machine (eg Virtualbox). Then follow the instructions on the wiki to get the sources and latest diff.

Reserved for files
Here you will find the up to date files related to the project.
Pichurri's full 2.6.27 install package is on the wiki here

You should correct the posts: 2.6.26 and 2.6.27 is the kernels used. More info: www.kernel.org

brumbrum said:
You should correct the posts: 2.6.26 and 2.6.27 is the kernels used. More info: www.kernel.org
Click to expand...
Click to collapse
We are using 2 kernels:
2.6.25 --> htc-msm-2.6.25 branch in git.linuxtogo.org. This is the kernel that we are testing in our machines these days.
2.6.27 --> htc-msm-2.6.27 branch in git.linuxtogo.org. Where we will stay in a few days. Better kernel, more improvements. Here is where people from other projects are working now.

orux said:
We are using 2 kernels:
2.6.25 --> htc-msm-2.6.25 branch in git.linuxtogo.org. This is the kernel that we are testing in our machines these days.
2.6.27 --> htc-msm-2.6.27 branch in git.linuxtogo.org. Where we will stay in a few days. Better kernel, more improvements. Here is where people from other projects are working now.
Click to expand...
Click to collapse
Sorry, my mistake. Typed the message above late in the night.
But in the first and second post in this thread it says 2.2.65 and 2.2.67.

Thanks, was posted in a rush, just pm me if you see more errors. We use the odd numbered dev kernels, they will always have the most recent stuff.

A challenge for someone who likes graphic drivers:
I think linux is using ~10% of epson controller capabilities.
We have a lot of information about this controller, and open source code from epson.
Perhaps someone would like to work with this stuff.

orux said:
A challenge for someone who likes graphic drivers:
I think linux is using ~10% of epson controller capabilities.
We have a lot of information about this controller, and open source code from epson.
Perhaps someone would like to work with this stuff.
Click to expand...
Click to collapse
Do you mean things like picture-in-picture? Would be good later on in the gui - multiple desktops, that kind of thing. Also I noticed the Epson controller handles TV-out. Do we know if the out-connection exists for this, or have they just not connected it up?
Another thing to consider maybe USB on-the-go - the MSM72xx supports it; if (big if) the usb port has the right connections, it would be possible to mount external storage.
But I think it's more for later on - core functionality would be about making calls, sms, GPRS/3G. Let's see what we get from the latest kernel. Orux have you talked to the RAPH/DIAM guys on irc about merging?

orux said:
A challenge for someone who likes graphic drivers:
I think linux is using ~10% of epson controller capabilities.
We have a lot of information about this controller, and open source code from epson.
Perhaps someone would like to work with this stuff.
Click to expand...
Click to collapse
what makes you believe that?
whatever makes you believe it, share it!
if you have anything like docs,etc to share or point to lets have it !

Blackstone has got 2 graphic processors:
--->mdp, inside the chip. We have drivers in the kernel (mdp.c, mdp_ppp.c ...) I am not sure what capabilities are being used in current kernel. There are not good docs about mdp processor (I haven't got any useful).
--->epson controller. It can do:
• Picture in Picture, Transparency, Alpha Blending
• Image Rotation (90°, 180°, 270°) and Mirroring
• Scroll Assist
• AME (Auto Movie Enhancement)
• Supports up to three layers
• Image Doubling
• Bi-Cubic Scaling (1/2x ~ 8x)
• Over/Down Sampling Scaling (1/8x ~ 8x)
• Edge Enhancement
We don't have driver support in current kernel, but we have docs and source code from epson (link posted in discussion thread).
Htc Touch Pro has a tvout usb cable adapter, and seems to work in linux! I don't know if this cable works with our device.
USB on-the-go: interesting TODO.
patp said:
Orux have you talked to the RAPH/DIAM guys on irc about merging?
Click to expand...
Click to collapse
Not yet; perhaps your (or pichurri, ...) task when we have a good .27 diff. I have too much language limitations for an on-line discussion

p3ngwin said:
what makes you believe that?
whatever makes you believe it, share it!
if you have anything like docs,etc to share or point to lets have it !
Click to expand...
Click to collapse
OK, OK! These things take time - we all have other jobs I guess. We plan to get any open source docs online in a systematic way, we just need to figure out a reliable way - ie not RS etc. And we have to be careful of proprietry materials - we don't want copyright lawyers after us...
If anyone wants to offer us some rock solid webspace, that would be awesome.

TODO: Investigate instability of screen
I think that problems with screen are caused by onscreen keyboard. This keyboard is an excellent hack, but it is not 100% integrated with android.
We need to test a kernel without it.

orux said:
I think that problems with screen are caused by onscreen keyboard. This keyboard is an excellent hack, but it is not 100% integrated with android.
We need to test a kernel without it.
Click to expand...
Click to collapse
Or use the cup cake version with the keyboard in android it self.

Full doc of the epson controler : http://vdc.epson.com/index.php?option=com_docman&task=cat_view&gid=278&Itemid=40
Link is at the bottom of the wiki, add yours
I don't think we need to put all the docs at the same place, just add links at the bottom of the wiki, either hosted or link to website.
I can provide hosting if you need, just pm me.

repository
what do you guys think about creating some kind of repository(git or svn) to upload and share our blackstone kernel? i think it would make development much easier if you could see changes of other people immediately. we could use github or sourceforge.

I also think the On-Screen Keyboard is a problem.
Earlyer today I was goofing around in Android and every time I moved the keyboard, the graphics started acting very weird.(scrolling, not updating etc.)
When I hit F5 on the OSK, it would refresh Android and go back to the home page and the screen would be normal again.
Maybe route the OSK to a pip on the epson?

It's git for kernel dev, anyways svn sucks (inc troll)
If we set up a git, we'll need a guy working as a maintainer and pulling from everyone. This may become usefull when people start working in many different areas of the kernel, but for now diffs are better as they can be easily shared, and there's a howto in the wiki.

patp said:
OK, OK! These things take time - we all have other jobs I guess. We plan to get any open source docs online in a systematic way, we just need to figure out a reliable way - ie not RS etc. And we have to be careful of proprietry materials - we don't want copyright lawyers after us...
If anyone wants to offer us some rock solid webspace, that would be awesome.
Click to expand...
Click to collapse
hey i have a servage account that i hardly use which has massive space and bandwidth i could give you a ftp account to and any sql servers you may need. let me know

Rewpparo said:
Full doc of the epson controler : http://vdc.epson.com/index.php?option=com_docman&task=cat_view&gid=278&Itemid=40
Link is at the bottom of the wiki, add yours
I don't think we need to put all the docs at the same place, just add links at the bottom of the wiki, either hosted or link to website.
I can provide hosting if you need, just pm me.
Click to expand...
Click to collapse
Agreed, the wiki is the best place for this. Would you be happy for me to mention your hosting offer on the front page (which will quite soon need a better structure I'm sure).

JanSchotsmans said:
I also think the On-Screen Keyboard is a problem.
Earlyer today I was goofing around in Android and every time I moved the keyboard, the graphics started acting very weird.(scrolling, not updating etc.)
When I hit F5 on the OSK, it would refresh Android and go back to the home page and the screen would be normal again.
Maybe route the OSK to a pip on the epson?
Click to expand...
Click to collapse
Now that my friend, is a stunning idea (if it can be done simply). How does it relate to the Android OSK mentioned by xmoo? I guess the linux one is low level whereas the Android one is basically an app in the gui. Advantages to both, but if it works out of the box, the android one would mean we could essentially get rid of the linux one. We have ssh if we want to type in a console (or maybe android terminal app?).

Windows Mobile App Repository

There is currently one app repository on XDA the thread is as follows.
http://forum.xda-developers.com/showthread.php?t=471576
However, I am trying to develop similar software which allows users to register with the website and create different profiles, create packages, revise packages, and search by device, WM version, package name and other traits.
For example, on my Kaiser I like to have the total commander, Skype, pocket rar, Google maps, and other software. I would like to be able to select the necessary programs either via PPC software or the website and automatically download and install the software on my devices. (a lot like tierautoinstaller) in addition when new versions come out I would like to have to option of automatically installing the updated version.
The package system would work much like Apt-get from the debian Linux distribution http://en.wikipedia.org/wiki/Apt_get. Each package would have an owner and contributors. The owner is the person who created it and can delete it. Contributors will have assignable powers to modify package information and release new versions of the program.
Each user will be able to select his/her packages and they will be saved in the database. The cabs will can to be retrieved from either the software on the device (still needs to be made) or the website (work in progress).
Currently I have a mySQL database as my backend and have created the basic dynamic webpages in perl which can browse, search, create and modify packages. Each package will have an external url and an internal cached copy for fault tolerances. More details will be disclosed as my development contuines.
If this sounds like something you will use or have any suggestions please let me know. Work has been kicking my butt lately but as soon as I finish the user registration part of the website I will put it up for a few test trials.
Pizzaroll
Mods: Since I currently own a Kaiser and only have software for a Kaiser I would like to keep this thread here until the initial testing phase is complete and I am ready to expand to other devices.

I don't get why there are 3-4 (likely 6-12) app stores out there, all incomplete, all with few apps listed. Rather than build another one, how about working with one which fits your ideas and contributing.
http://forum.xda-developers.com/showthread.php?t=480476
http://forum.xda-developers.com/showthread.php?t=436127
And even one to browse Freeware PocketPC:
http://forum.xda-developers.com/showthread.php?p=3268926

[DEVS ONLY] Crack/bypass/trick Boot.img Signature

Ok, so lets get cracking on this bootloader.
boot.img and recovery.img certs (thanks to ntwrkwizard):
http://ponack.net/designgears/atrix/mmcblk0p10 - cert extract.zip
http://ponack.net/designgears/atrix/mmcblk0p11 - cert extract.zip
Flaw in the X.509 certs:
http://www.darkreading.com/security/vulnerabilities/218900008/index.html
Boot.img & Recovery.img
http://www.ponack.net/designgears/dump.7z

DG, afaik, that exploit deals with the md2 hash algorithm. it is a good possible starting point. has the signing cert been found/recovered/viewed yet?
if moto signed it with an md5 hash cert, then that may not be possible.

Well if you guys need any processing power to help crack anything let me know. I am willing to donate my system. Current specs:
i7-970 six core 4.8ghz overclocked
4 gtx580 gpus
24gb ddr3 2000
HSDL 240gb ssd
Like I said, if you guys need any processing power let me know.
Sent from my "5 inch Galaxy Tab"
Atrix here on the 22nd

dtmcnamara said:
Well if you guys need any processing power to help crack anything let me know. I am willing to donate my system. Current specs:
i7-970 six core 4.8ghz overclocked
4 gtx580 gpus
24gb ddr3 2000
HSDL 240gb ssd
Like I said, if you guys need any processing power let me know.
Sent from my "5 inch Galaxy Tab"
Atrix here on the 22nd
Click to expand...
Click to collapse
Please don't post here. This is a dev only thread. Post your offer in General.
Thanks!

These downloads look like just CA certs. Could someone extract the x.509 cert embedded in the beginning of the boot.img and post it to this thread? I'm out and about this weekend and don't have a box with a hex editor handy.

perdurabo2 said:
These downloads look like just CA certs. Could someone extract the x.509 cert embedded in the beginning of the boot.img and post it to this thread? I'm out and about this weekend and don't have a box with a hex editor handy.
Click to expand...
Click to collapse
If you could tell me how to do that I will be more than happy to get those for you. I'm the go to guy, remember?

Here is the extracted cert from within mmcblk0p10.img. This hex dump is extracted from 7FF7FC through 7FFDF9.
Also is the extracted cert from within mmcblk0p11.img. This hex dump is extracted from 7FF7FC through 7FFE79.
Not sure the value of an extracted public side of the x.509 is post signature but I'm sure someone will define that.
Good luck..
NW

back on topic please.

Mr. Clown said:
back on topic please.
Click to expand...
Click to collapse
Who are you talking to? The cert conversation is applicable.

Hi friend,
is the bootloader encrypten the same as defy or milestone?
Or a new one?
Maybe we could get all a free bootloader if this would work?
Or other technical?
Thanks

perdurabo2 said:
Who are you talking to? The cert conversation is applicable.
Click to expand...
Click to collapse
He deleted some unnecessary posts which were getting off topic. That's all.

The structure of an X.509 v3 digital certificate is as follows:
Certificate
Version
Serial Number
Algorithm ID
Issuer
Validity
Not Before
Not After
Subject
Subject Public Key Info
Public Key Algorithm
Subject Public Key
Issuer Unique Identifier (optional)
Subject Unique Identifier (optional)
Extensions (optional)
...
Certificate Signature Algorithm
Certificate Signature
Click to expand...
Click to collapse
The extensions they come in are:
pem - (Privacy Enhanced Mail) Base64 encoded DER certificate, enclosed between "-----BEGIN CERTIFICATE-----" and "-----END CERTIFICATE-----"
.cer, .crt, .der - usually in binary DER form, but Base64-encoded certificates are common too (see .pem above)
.p7b, .p7c - PKCS#7 SignedData structure without data, just certificate(s) or CRL(s)
.p12 - PKCS#12, may contain certificate(s) (public) and private keys (password protected)
.pfx - PFX, predecessor of PKCS#12 (usually contains data in PKCS#12 format, e.g., with PFX files generated in IIS)
PKCS#7 is a standard for signing or encrypting (officially called "enveloping") data. Since the certificate is needed to verify signed data, it is possible to include them in the SignedData structure. A .P7C file is a degenerated SignedData structure, without any data to sign.
PKCS#12 evolved from the personal information exchange (PFX) standard and is used to exchange public and private objects in a single file.
Click to expand...
Click to collapse
Flaws in the X509 Certificate:
Specification: Complexity and lack of quality
The X.509 standard was primarily designed to support the X.500 structure, but todays use cases center around the web. Many features are of little or no relevance today. The X.509 specification suffers from being over-functional and underspecified and the normative information is spread across many documents from different standardization bodies. Several profiles were developed to solve this, but these introduce interoperability issues and did not fix the problem.
Architectural flaws
Use of blacklisting invalid certificates (using CRLs and OCSP) instead of whitelisting
CRLs are particularly poor because of size and distribution patterns
Ambiguous OCSP semantics and lack of historical revocation status
Revocation of root certificates not addressed
Aggregation problem: Identity claim (authenticate with an identifier), attribute claim (submit a bag of vetted attributes) and policy claim are combined in a single container. This raises privacy, policy mapping and maintenance issues.
Delegation problem: CAs cannot technically restrict subCAs to issue only certificates within a limited namespaces and attribute set – this feature of X.509 in not in use. Therefore a large number of CAs exists in the Internet, and classifying them and their policies is an insurmountable task. Delegation of authority within an organization cannot be handled at all, like it is common business practice.
Federation problem: Certificate chains that are the result of sub-CAs, bridge- and cross-signing make validation complex and expensive in terms of processing time. Path validation semantics may be ambiguous. Hierarchy with 3rd-party trusted party is the only model. This is inconvenient when a bilateral trust relationship is already in place.
Problems of Commercial Certificate Authorities
Flawed business model: The subject, not the relying party, purchases certificates. The RA will usually go for the cheapest offer; quality is not being paid for in the competing market.
CAs deny almost all warranties to the user.
Expiration date: Should be used to limit the time the key strength is deemed sufficient. Abused by CAs to charge the client an extension fee. Places unnecessary burden on user with key roll-over.
Client certificates have zero protection value against dedicated attackers.
In browsers, the security is that of the weakest CA. There are very weak CAs.
“Users use an undefined certification request protocol to obtain a certificate which is published in an unclear location in a nonexistent directory with no real means to revoke it.“
Implementation issues
Implementation suffer from design flaws, bugs, different interpretations of standards and lack of interoperability of different standards. Some problems are:
Many implementations turn off revocation check:
Seen as obstacle, policies are not enforced
Would it be turned on in all browsers by default, including code signing, it would probably crash the infrastructure.
DNs are complex and little understood (lack of cononicalization, i18n problems, ..)
rfc822Name has 2 notations
Name and policy constraints hardly supported
Key usage ignored, first certificate in a list being used
Enforcement of custom OIDs is difficult
Attributes should not be made critical because it makes clients crash.
Unspecified length of attributes lead to product-specific limits
Exploits
In 2005, Arjen Lenstra and Benne de Weger demonstrated "how to use hash collisions to construct two X.509 certificates that contain identical signatures and that differ only in the public keys", achieved using a collision attack on the MD5 hash function.
In 2008, Alexander Sotirov and Marc Stevens presented at the Chaos Communication Congress a practical attack that allowed them to create a rogue Certificate Authority, accepted by all common browsers, by exploiting the fact that RapidSSL was still issuing X.509 certificates based on MD5.
X.509 certificates based on SHA-1 had been deemed to be secure up until very recent times. In April 2009 at the Eurocrypt Conference , Australian Researchers of Macquarie University presented "Automatic Differential Path Searching for SHA-1" . The researchers were able to deduce a method which increases the likelihood of a collision by several orders of magnitude.
Domain-validated certificates („Junk certificates“) are still trusted by web browsers, and can be obtained with little effort from commercial CAs.
EV-certificates are of very limited help, because Browsers do not have policies that disallow DV-certificates,
There are implementation errors with X.509 that allow e.g. falsified subject names using null-terminated strings or code injections attacks in certificates.
Click to expand...
Click to collapse
From the sound of it, the X.509 cerificate the Atrix uses will be in .p12 format, although I could be wrong.
Example of a Decoded X509 cert: http://pastie.org/1590676

Great post, this is def a way to go and explore , i have been messsing with NVIDIAFlash all day so far.. i think if i can get a bootstrap or something on here so that i can mount and add some files to system folder with phone off i may be on to something ..

t0dbld said:
Great post, this is def a way to go and explore , i have been messsing with NVIDIAFlash all day so far.. i think if i can get a bootstrap or something on here so that i can mount and add some files to system folder with phone off i may be on to something ..
Click to expand...
Click to collapse
Adding things to the system folder means nothing, the system partition is only check when a new system is flashed via (sbf_flash, rsdlite, or flashing a CG via an update.zip) otherwise you can add/remove items from the /system partition with no worries of the signatures.

I've got a question. Since we are dealing with a closed system. Can we not validate -enddate of the signed boot image. Make note of the exact date and time. Then change the system clock to less than 24 hrs. after this date. This will allow the entire system to think that the bootloader and cert have done their job and simply needs updated. Now we simply need to insert new boot.img that has a valid -startdate within that 24 hr period. The system should simply stop using the expired image and boot the "updated image". Once this generic image is booted, it can simply be swapped out with any further custom roms that we feel the need to use. Once all is done, the system clock will need to be restored to appropriate time. If I knew how to code, I would simply try this myself. But I don't, so I hope this might at least provide some insight to the possibility. I would love to work with developers on finding a solution to this problem, so feel free to ask questions.

jimmydafish said:
Adding things to the system folder means nothing, the system partition is only check when a new system is flashed via (sbf_flash, rsdlite, or flashing a CG via an update.zip) otherwise you can add/remove items from the /system partition with no worries of the signatures.
Click to expand...
Click to collapse
I 100% agree i didnt say that was the end all.... the reason for doing this is so that the computer recoginizes the device in NVIDIAFlash mode and i than can hopefully overwrite the bootloader with the dev version of bootloader.bin

t0dbld said:
I 100% agree i didnt say that was the end all.... the reason for doing this is so that the computer recoginizes the device in NVIDIAFlash mode and i than can hopefully overwrite the bootloader with the dev version of bootloader.bin
Click to expand...
Click to collapse
That will not work, the bootloader is just one piece of a longer chain..changing that out "will" just have the phone reboot and use the backup bootloader. The problem to cracking it lies in all parts. Especially the NvRam where it begins and the MBR.

jimmydafish said:
That will not work, the bootloader is just one piece of a longer chain..changing that out "will" just have the phone reboot and use the backup bootloader. The problem to cracking it lies in all parts. Especially the NvRam where it begins and the MBR.
Click to expand...
Click to collapse
I very much respect all of the work you and your team has put into this situation with other devices, and i very much appreciate the help given by you guys to this forum, and no one including myself wants to waste time, so that being said i have not seen any ideas contributed ... only negative posts on what isnt going to work, i agree that you guys know more than me on this situation perhaps if you could share some of your ideas or the approach or direction you are going i and others could be of some help. We our fresh and not quite so beat up , its like when debuging a program thats driving you nuts and you cant figure out whats going wrong , sometimes a break, sleep, etc is in order so that when you come back your whole train of thought has been altered and you see something differently because you were not looking there before.
I follow instructions well, so lead... i am willing to donate my time my resources, and more than likely my device (at least for the next 29 days )

t0dbld said:
I very much respect all of the work you and your team has put into this situation with other devices, and i very much appreciate the help given by you guys to this forum, and no one including myself wants to waste time, so that being said i have not seen any ideas contributed ... only negative posts on what isnt going to work, i agree that you guys know more than me on this situation perhaps if you could share some of your ideas or the approach or direction you are going i and others could be of some help. We our fresh and not quite so beat up , its like when debuging a program thats driving you nuts and you cant figure out whats going wrong , sometimes a break, sleep, etc is in order so that when you come back your whole train of thought has been altered and you see something differently because you were not looking there before.
I follow instructions well, so lead... i am willing to donate my time my resources, and more than likely my device (at least for the next 29 days )
Click to expand...
Click to collapse
I am not being negative just helping you all steer clear of dead ends. We are looking over some files now and may have some useful tidbits soon. I think we can tell the boot chain from start to finish.

Great!! thanks for the update... on a side note esp in loom of this whole ps3 thing i hope motorola uses the same signing keys for all devices, so that if our day ever comes its x-mas for all

[Q] How to find share folder in LAN - Windows Phone Development

Hi guys,
This is my first post in XDA and this question should be posted in "Windows Phone 8 Development and Hacking" but unfortunately, i don't have the minimum requirements of 10 posts for the Development and Hacking Section so i am hoping for someone to give me a push here.
I am looking for a way to access my shared folder on my LAN through Windows Phone Application. I have downloaded a sample from Microsoft which uses File Picker. When i run the project as a windows store application I select network, I type the UNC path and I can browse the folders, but when i run it in phone emulator the network option does not exists. I have searched Google for an example on how to enumerate shared folders in my LAN and i have not found any solution.
So if someone could help me it would be really appreciated.
Thank you

First of all, no, this thread *DEFINITELY* belongs where you put it. System working as intended. This is a Q, it goes in Q&A. It is neither something you've developed nor a hack to share, it does not go in D&H.
With that said, the problem is unfortunately simple: WP8 doesn't (seem to) support Windows networking (SMB) at all, so far as I can tell. This is somewhat odd, since it has both the LanmanServer and LanmanWorkstation services, which are responsible for providing Windows Networking support, plus all the relevant binaries appear to be present. This warrants further investigation!
You can, in theory, implement it using sockets (see Samba for an open-source implementation of SMB, though note that it is GPL code and if you use it you must open-source your application as well) in any case.

[Q] Noob questions on Windows8

Hi all,
i've never used a windows phone, so i've some questions related:
I've seen three license types: student, develop, interop. If i've understood well, these three licenses differ each other on the number of unsigned apps that can be installed into the device (3,10,unlimited). If i have a develop license, the 10 apps limit can be considered "in total" or "in the same time"?For example, can i deploy 10 unsigned apps for one month and 10 new apps the next one?
A signed app downloaded from the store is always encrypted even if the developer doesn't encrypt the code?
Which license i need to exfiltrate an appx file?
If i change the code of a signed appx, can i deploy it on my phone?I need a particular license?
If i need to resign a changed appx, how can i do it?
Thanks

This really doesn't belong in the General forum, more fitted for Q&A.
The FAQ should fix almost all of your problems.