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Welcome to the third part of Android security structure, in this lecture, we will talk about encryption

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and specifically encryption at rest right now.

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Android version 5.0 and later.

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So for quite some time, they actually supports full disk encryption and then from Android seven data

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and later it actually supports Flyte based encryption as well and basically favors encryption, allows

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different files to be encrypted with different keys that can be used to decrypt or decrypted or unlogged

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independently.

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OK, another thing that I want to cover here is the application signing.

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So application signing allows developers to identify the author of the application so that the user

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knows that the application is actually legitimate and also to update their application without creating

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complicated interfaces or permissions.

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Right now, every application that is run on the Android platform by default must be signed by the developer.

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So if you wrote it and you go to some other stores, that's definitely a very different applications

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that actually attempt the story without being signed by default are rejected by either Google Play or

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the package installer on the Android device now on Google Play.

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Developers know their application is actually provided by them or modified by them, and the developers

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actually can be held accountable for the behavior of the application.

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But of course, if it's modified, then all bets are off.

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Right now on Android applications, I think is the first step to placing an application in its application

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sandbox.

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OK, the sign applications are difficult to define video that it is actually associated with video applications

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and then different applications run under a different user I.D..

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Now, application signing ensures that one application cannot access another application except through

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a well-defined IPC.

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Now, when an application or a bigger files, basically applications are a bigger file than ever.

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These are installed on an Android device.

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The package manager is the entity that actually verifies that the EPICA has been properly signed on

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with the certificate included in the applicant.

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If the certificate or more accurately, the actual publicly in a certificate matches the key that is

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actually used to sign any other APJ in a device, then UAP actually has the option to specify the manifest

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that it will actually share a user I.D. with other.

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Similarly, sign it, because right now applications can be signed by a third party, OEM or any other

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type of marketplaces.

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In a lot of cases, actually, some enterprises may have their own app, so they have a different market

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will get it not only because the device has been routed and you want to get a free game from some other

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market.

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But in some cases, actually there are some legitimate stores that are alternate markets that applications

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actually need to be signed and those are actually signed with a third party or selfsame certificate.

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Now, applications do not have to be signed by a central authority, and Android currently does not

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perform any certificate authority verification for application certificates.

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And that can be actually huge in the case of security, because it may actually lead to a security compromise

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if you don't verify the CEO verification.

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Of course, it's a little bit different to skill whenever you provide the operating system and you have

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many different implementers in comparison to, let's say, Apple, that they actually control all the

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devices.

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And it's not like Apple uses running in other vendors hardware.