Develop Reference

Android SDK for fingerprint matching - External device

I'm developing an Android application that uses U.are.U 4500 fingerprint reader to identify users. I already have a backend server, that uses SQL Server, to store and register user data and now I need my app to be able to read the user fingerprint and verify if this fingerprint matches any of the fingerprints on the database. Does anyone know a SDK that is able to do this comparison?
I'm using asia.kanopi.fingerscan package to read the user fingerprint and I already have the scan working, now I only need to get this image and compare to the data on the SQL database. I saw a few answers here on StackOverflow telling me to use openCV library for Android, but none of them could give me any lead on how to do it.
I based my development on this tutorial: https://medium.com/touch4it/fingerprint-external-scanner-with-usb-database-sdk-64c3ec5ea82d, but unfortunately I couldn't find the SDK IDKit Fingerprint SDK Mobile anywhere.
How can I sucessufully match the image with the one stored on the database?

For those who are still looking for an answer to this problem. It's been a while since I actually implemented my solution and, when I did it, I added this line to my app gradle file:
com.github.lmone:SourceAFIS-Android:v3.4.0-fix3
But now I can't seem to find the github link anywhere. Maybe the repository got deleted. If someone find it, please send it to me so I can update my answer here.
Besides that, if you can still add the library to your Android project, the basic idea is to use a FingerprintMatcher to compare two FingerprintTemplate.
Example:
FingerprintTemplate probe = new FingerprintTemplate().dpi(500).create(digital_byte_array);
while (result.next()) {
byte[] imgCandidate = digital_to_compare;
FingerprintTemplate candidate = new FingerprintTemplate()
.dpi(500)
.create(imgCandidate);
double score = new FingerprintMatcher()
.index(probe)
.match(candidate);
if (score >= 40) {
// Found a match
}
}
In my case, I found the performance a little slow. It was usable, but nothing compared to Android's built-in fingerprint device. Also, the bigger your digitals collection, the longer it will take to find a match.
The score of the match is up for you to decide what suits better your project. 40 was a reliable amount in my case. The same goes to the FingerprintTemplate dpi.
Also, the method .create() receives a byte[] as parameter.
EDIT
I found this link and I'm almost certain it is the library I used, but under a new repository name:
https://github.com/robertvazan/sourceafis-java
The docs looks just the same as the code I used: https://sourceafis.machinezoo.com/java

To match a user on server side, you have to use an AFIS server : https://en.wikipedia.org/wiki/Integrated_Automated_Fingerprint_Identification_System
Here some providers of AFIS solution:
http://www.neurotechnology.com/megamatcher.html
https://www.nec.com.au/expertise/safety-security/identity-access/fingerprint
https://www.innovatrics.com/innovatrics-abis/
https://www.dermalog.com/products/software/civil-afis-abis/
http://www.m2sys.com/automated-fingerprint-identification-system-afis/

Using JCESecurityModule on Android device

While trying to carry out an encryption and decryption process on an Android environment, i have the below log.
com.s.sdk.security.SMException: Error loading Local Master Keys, file:
"/cfg/lmktest.lmk" does not exist. Please specify a valid LMK file, or
rebuild a new one. 09-21 11:56:31.792 16182-16182/com.mpos.sdk
W/System.err: at
com.s.sdk.security.jceadapter.JCESecurityModule.init(JCESecurityModule.java:1785)
09-21 11:56:31.792 16182-16182/com.mpos.sdk W/System.err: at
com.s.sdk.security.jceadapter.JCESecurityModule.(JCESecurityModule.java:159)
The reason why I will want to make use of JPOS is simply because I will want to carry out a financial transaction, which will be used in packaging my message.
For the encryption and decryption of data, I am to make use of this JCESecurityModule which works well on other platform, but not on the android OS.
NOTE: The file location in my android studio is app/cfg/test.lmk
I was able to get this file from the JPOS-master on github found in the jPOS-master\jPOS-master\jpos\src\test\resources\org\jpos\security
i.e the lmk-test
which was been used this way
JCESecurityModule sm = new JCESecurityModule("app/cfg/test.lmk");
I have also tried rebuilidng the lmk file, using the below method
public JCESecurityModule (String lmkFile) throws SMException
{
init(null, lmkFile, true);
}
which can be found in the JCESecurityModule class (JPOS)
was still having same issue in loading the lmk file
Thanks

For the sake of completeness, this was also asked on the jPOS's Google Group, and discussed there. https://groups.google.com/forum/#!topic/jpos-users/X3r_PX7lgd4

The encryption was done by a device which is to be connected to a mobile phone to carrying out transactions, but the device makers actually did it this way to provide end to end encryption which you are circumventing. You don't need jpos in the device. You need it at your centrally deployed servers, where you would use real HSMs.
by Victor Salaman
in JPOS users google group https://groups.google.com/forum/#!topic/jpos-users/X3r_PX7lgd4
but you can still carry out the encryption and decryption using some other Module instead of the JCESecurityModule (if the problem still persist). e.g. using the SunJCE

Content Provider authorities

I am inheriting a code base that needs to be kept fairly in sync with the previous version to make updating to new versions as painless as possible when they push the changes via git. The changes I am making are related to re-styling and adding new features.
In the latest release, I was trying to install both the original version of the app alongside this custom version and got this error:
Failure [INSTALL_FAILED_CONFLICTING_PROVIDER]
I looked through my source control and found that in previous versions I was using the same authorities and name as the parent app, but I don't recall having this problem, but maybe I just never tested the case where both apps were installed at the same time?
In the original version of the manifest, this is the provider element:
<provider
android:name="com.foo.mobile.android.provider.Provider"
android:authorities="com.foo.android.mobile.contentprovider"
android:exported="false" />
I tried changing the authority to this:
<provider
android:name="com.foo.mobile.android.provider.Provider"
android:authorities="com.bar.android.mobile.contentprovider"
android:exported="false" />
But now the app crashes shortly after launch with SecurityException:
java.lang.SecurityException: Permission Denial: opening provider com.foo.mobile.android.provider.Provider from ProcessRecord{42cbc998 2462:com.bar/u0a191} (pid=2462, uid=10191) that is not exported from uid 10189
I've looked on SO and saw a couple of questions regarding this topic and also looked at the documentation and it all says I need this authorities to be different, but how can I keep this different while keeping synergy with the base code?

maybe I just never tested the case where both apps were installed at the same time?
I would presume this is the case. You cannot have two apps with providers supporting the same authority installed at the same time.
But now the app crashes shortly after launch with SecurityException:
My guess is that you changed your manifest, but you did not change the Uri that you are using to access the provider. Hence, your com.bar app is still trying to talk to the com.foo provider, and that provider is not exported.
how can I keep this different while keeping synergy with the base code?
Either this is the same app, or it is not.
If it is the same app, your first step is to switch back to the original package name. The only way you could have gotten Failure [INSTALL_FAILED_CONFLICTING_PROVIDER] is because you changed the package name and did not change the provider's authority. Changing the package name means that, from the standpoint of everyone outside of you and your team, it is a completely different app. Once you have switched back to the original package name (and rolled back to the original provider authority), everything should be fine, except that you won't be able to have the release version and the development version on the same device at the same time.
If you do indeed plan to have this app have a separate package name (so existing users of the existing app cannot upgrade to this new app), you will need to change the authority string in all relevant places. I presume that you can do this using a string resource, where you have different versions of the string resource. Or, if this is a free-vs.-paid app scenario, move to doing your builds using Gradle for Android, and set up separate free and paid product flavors, which can patch up your package name and authority data as part of the builds, without having to tweak the source code.

Issues with application signature

I'm trying to create my own version of Gesture Builder. In eclipse I selected android project from existing code and I renamed the project and package name to new gesture. Then I added in android:fadeOffset = "1000" in create gesture xml(so that I can create gestures for letters like t and f) and in AndroidManifest.xml I set the version name to NewGestures and I set a different icon but when I try to run it I get this error message:
"Re-installation failed due to different application signatures. You must perform a full uninstall of the application. WARNING: This will remove the application data! Do you want to uninstall?"
From what I've seen online I need to match the signature used originally on Gesture Builder, but I've no idea how to do this on eclipse, shouldn't the signature have been handled properly when I created from existing code? Any help would be very much appreciated. I just need this app working so I can get a gestures library for a different application I'm working on for college.

This message concerns the application signature. This happens when you are trying to install an application on your device while an application of the same package name is already installed, but signed with a different certificate (see details here).
For example:
You have exported and installed your application using your Google Play keystore (so using your actual developer's certificate), and now you are running/debugging it from Eclipse, implicitely using the debug certificate (which is different)
You have runned/debugged your application from Eclipse at home on this device, and now your are running it/debugging it from Eclipse with another computer (which is using a different implicit debug certificate)
etc
Normally, below the error message, you have a button that allows uninstalling/reinstalling. If not, just uninstall your app manually and everything will be fine again.

versionName:
The version number shown to users. This attribute can be set as a raw
string or as a reference to a string resource. The string has no other
purpose than to be displayed to users.
package:
The package name serves as a unique identifier for the application.
The package name declared in your manifest.xml is what makes your application unique. Therefore, there can not be two application installed with the same package name at the same time. If you try this, your error occurs.

Share WiFi-Settings as QR-Code for WPA2 Enterprise

I have found several sources describing a String Format used to describe WiFi-Access Settings in the form of:
WIFI:T:WPA;S:mynetwork;P:mypass;;
(example taken from zxing documentation)
For basic WPA-Connections, this works just fine on my Android Device using the Zxing-Barcode-Scanner-App. However, I have been unable to find a way to embed WPA2/EAP-Connection Settings (Also referred to as WPA2 Enterprise) into a scannable 2D-Code. As I expected, inserting "L" (Login), "N" (Name) or "I" (Identification) Parameters at random positions did not really bring any advance.
Has anyone here succeeded in "embedding" WiFi-Connection Settings into a 2D-Scannable Code to work with an Android device?
Thanks for your help!

I found some information on how to format the WiFi config string in the following pull request at the github page of the zxing library project: https://github.com/zxing/zxing/pull/865
The first post contains a template of the string format, including an error (the prefix AI: is wrong, it must read A:, see here). The correct format according to the source is thus:
WIFI:T:WPA2-EAP;S:[network SSID];H:[hidden?];E:[EAP method];PH2:[Phase 2 method];A:[anonymous identity];I:[username];P:[password];;
When I tried this (using the command line tool qrencode) my Barcode Scanner app crashed. After some trial and error I figured that the option for hiding the SSID can be left out:
WIFI:T:WPA2-EAP;S:[network SSID];E:[EAP method];PH2:[Phase 2 method];A:[anonymous identity];I:[username];P:[password];;
With this I'm getting a working entry in the list of known wireless networks in Android 8.
As of now there is no support for declaring a certificate and the respective domain. If this is needed, one can specify it later by adjusting the settings from inside Android's WiFi menu.