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Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

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Archive for the ‘Mobile Development’ Category

SMS Backup+ – Apps on Google Play

Posted by jpluimers on 2020/03/04

Simple but cool app: [Archive.isSMS Backup+ – Apps on Google Play:

Automatically backup your SMS, MMS and call history with a separate label in Gmail and Google Calendar.

Later you can restore the saved data (except MMS) back to the phone, especially useful when switching to a new device.

IMAP access needs to be manually enabled in Gmail, see the website and FAQ for more information. You can of course use your own IMAP server for backups, giving you full control over your data.

SMS Backup+ is a free open-source project which has been in active development since the early days of Android, completely ad and tracking-free, supported through voluntary donations.

Sourcecode: [WayBack] GitHub – jberkel/sms-backup-plus: Backup Android SMS, MMS and call log to Gmail / Gcal / IMAP

Via: [WayBack] Wirre Telefongespräche für 500. Ich kriege ja nicht mehr oft Anrufe auf der deutschen Telefonnummer, und so liegt das Telefon jetzt daheim und hängt am… – Kristian Köhntopp – Google+

–jeroen

Posted in Android, Development, Mobile Development, Software Development | Leave a Comment »

Commander One review: A superior alternative to Android File Transfer on Mac

Posted by jpluimers on 2020/01/10

On my list of software to try: [WayBackCommander One review: A superior alternative to Android File Transfer on Mac

Via: [WayBack] Looks like a must-have for anyone using a Mac (with MacOS) and an Android phone. – Roderick Gadellaa – Google+

–jeroen

Posted in Android, Android Devices, Apple, Development, iMac, Mac, Mac OS X / OS X / MacOS, MacBook, MacBook Retina, MacBook-Air, MacBook-Pro, MacMini, macOS 10.12 Sierra, macOS 10.13 High Sierra, Mobile Development, Software Development | Leave a Comment »

Some links on keystore, encryption and decryption on Android

Posted by jpluimers on 2019/02/06

For my link archive:

 

Basically:

  • storing encrypted data plus IV in preferences is OK
  • store the symmetric encryption key (for instance an AES one) in the keystore for the application
  • likely a salt is also needed, then store the salt with the IV and encrypted data

–jeroen

Presumptions:

  • The keystore of a specific application UUID is only accessible by only that application UUID when the device has been unlocked by the user
  • The keystore saves credentials in a secure way
  • It is OK to save both the encrypted data and associated IV

Approach (plain data is “hashed application PIN”, encrypted data is “encrypted hashed application PIN”:

  1. store a symmetric AES key in the application key store
  2. after entering application PIN:
    1. hash the application PIN
    2. use the hashed application PIN to to enter the application
    3. from the keystore, obtain the symmetric AES key
    4. create a cipher based on the AES key
    5. use the cipher to obtain an IV, and to encrypt the hashed application PIN
    6. store the encrypted hashed application PIN and IV both in the application preferences
  3. when needing to enter the application, present the user to either enter the application PIN again or proof that they can pass the device unlock sequence (using an unlock activity)
    1. if the user provided the application PIN, then:
      1. hash the application PIN
      2. try to enter the application with the hashed application PIN
    2. proved the device unlock, then:
      1. from the preferences, obtain the IV and encrypted hashed application PIN
      2. from the keystore, obtain the symmetric AES key
      3. create a cipher based on the AES key
      4. decrypt the encrypted hashed application PIN using the cipher and the IV into the hashed application PIN
      5. try to enter the application with the hashed application PIN

Posted in Android, Development, Mobile Development, Software Development | Leave a Comment »

Quick Intro Into Actions on Google | Grokking Android

Posted by jpluimers on 2019/01/30

Hopefully by now the Google Assistant and Google Home have made their way into the Dutch language. If so, then it’s time for me

[WayBackQuick Intro Into Actions on Google | Grokking Android: Find out which options exist to develop apps for the Google Assistant with Actions on Google and to bring the Assistant to devices with the Assistant SDK.

–jeroen

 

Posted in Android, Android Devices, Development, Google, Google AI, Google Assistant, GoogleHome, Mobile Development, Software Development | Leave a Comment »

Don’t forget your padding… playing with the APK format of a sample “Hello world” Android app

Posted by jpluimers on 2019/01/23

Don’t forget your padding: Hello,I’m playing with the APK format of a sample “Hello world” Android application.my (first) goal is to be able to rebuild an APK from a unzipped one… – Paul TOTH – Google+

References: RSA Algorithm

–jeroen

Posted in Android, Development, Encryption, Mobile Development, Power User, Security, Software Development | Leave a Comment »

 
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