Understanding Provisioning Profiles and Certificates | Xcode | iOS App Development

Summary

In this icode tutorial, Pallav delves into the intricacies of provisioning profiles and certificates for iOS app development. He explains the concept of code signing, ensuring the integrity of the code, and its necessity for app security. The video clarifies what provisioning profiles are, their components, and their role in linking developers and devices to authorized development teams. Pallav also discusses different types of profiles and how code signing works using public-private key pairs. Aimed at beginners, this video demystifies common errors and enhances understanding of iOS app security mechanisms.

Takeaways

• 🔐 Code signing is the digital signature of your code to ensure its integrity and security.
• 📜 Provisioning profiles act as a bridge between the developer account and devices, defining which apps can run on which devices.
• 📱 iOS devices need to be provisioned by Apple before you can run your app on them during development.
• 🛠 A provisioning profile includes development certificates, unique device identifiers, and the app ID.
• 🔗 The app ID in a provisioning profile is crucial for determining if an app is authorized to run on a device.
• 🖥️ When you build an app in Xcode, several checks are performed to ensure the certificate, device UUID, and app ID match the provisioning profile.
• 📲 There are different types of provisioning profiles: development, ad hoc, enterprise, and distribution.
• 🔄 Code signing uses public-private key pairs and asymmetric cryptography to ensure the source code hasn't been tampered with.
• 📤 To get a developer certificate, you must create a Certificate Signing Request (CSR) which includes a public key.
• 🔑 The private key on your machine is used to sign the app, and it must match the public key in the certificate for successful installation.

Q & A

What is the primary purpose of code signing?

The primary purpose of code signing is to digitally sign your code, ensuring that after a certain point, your code cannot be modified, thereby making it more secure.

How does a provisioning profile act as a link between a developer account and devices?

A provisioning profile acts as a link by uniquely tying developers and their devices to an authorized iPhone development team, allowing the app to run on specified devices and access certain services.

What does a provisioning profile contain?

A provisioning profile contains development certificates, unique device identifiers, and the app ID, which authorizes test devices, identifies designated devices for app installation, and verifies the app's authorization to run on a device.

What happens when you hit Command + R in Xcode?

When you hit Command + R in Xcode, it initiates the installation process. After the build is done and there are no compilation errors, several checks are made, including matching the developer certificate, authenticating the device, and verifying the app ID and entitlements before the app can be installed.

Why are there different types of provisioning profiles, and what are they?

There are different types of provisioning profiles to cater to various stages of app distribution: development, ad hoc, enterprise, and distribution. Development profiles are used for testing on specific devices, ad hoc profiles for a larger audience not part of the Apple Developer program, and distribution profiles for app store submission.

How does code signing provide a sense of trust and confidence in the source code?

Code signing provides trust and confidence by using a public-private key pair, ensuring that the source code has not been modified since it was signed, similar to how a sealed envelope ensures the security of its contents.

What is a Certificate Signing Request (CSR) and why is it necessary?

A Certificate Signing Request (CSR) is a block of encoded text that contains the public key generated from your machine. It is necessary to get the developer certificate from Apple, as it embeds the public key in the request, which Apple uses to create the certificate.

How does the process of asymmetric cryptography work in the context of code signing?

Asymmetric cryptography in code signing works by using a public-private key pair. The private key signs the code, and the public key, which is embedded in the certificate, verifies the signature, ensuring the code's integrity and authenticity.

What happens if there is a mismatch between the provisioning profile and the certificate in the keychain?

If there is a mismatch between the provisioning profile and the certificate in the keychain, the app installation will fail. This could be due to an expired certificate, incorrect device identifiers, or a mismatched app ID.

Why might an app icon appear greyed out in Xcode?

An app icon might appear greyed out in Xcode if one of the checks during the installation process fails, such as a mismatch in the developer certificate, device UUID, app ID, or entitlements.

Outlines

00:00

🔐 Understanding Code Signing and Provisioning Profiles

The video begins with the host, Pallav, introducing the topic of provisioning profiles and certificates, which are crucial for iOS app development. He acknowledges the initial confusion faced by beginners and aims to clarify the concepts. Code signing is introduced as the digital signing of code to ensure its integrity and security. The analogy of sending a sealed envelope to ensure the security of sensitive information is used to explain the purpose of code signing. Provisioning profiles are explained as digital entities that link developers and their devices to an authorized iPhone development team, allowing specific devices to run the app during development. The video promises to delve into the use, necessity, and workings of provisioning profiles and certificates.

05:00

📱 Deep Dive into Provisioning Profiles and App Installation Process

This paragraph delves deeper into the specifics of provisioning profiles, explaining their role in the app development process. It details the contents of a provisioning profile, which includes development certificates, unique device identifiers, and the app ID. The paragraph also outlines the process of installing an app from Xcode, highlighting the checks made during the installation process, such as matching the developer certificate, code signing the bundle, and verifying the device's authenticity and app's entitlements. The different types of provisioning profiles—development, ad hoc, enterprise, and distribution—are introduced, with a focus on their specific uses and limitations. The paragraph concludes with an explanation of how code signing works using public-private key pairs and the role of asymmetric cryptography in ensuring the integrity of the source code.

10:02

🔑 Certificate Signing Request and Code Signing Process

The final paragraph discusses the creation of a Certificate Signing Request (CSR) and the code signing process. It explains that a CSR involves generating a public-private key pair on the developer's machine, with the public key being sent to Apple. Upon approval, Apple issues a certificate that is matched with the private key on the developer's machine. This process ensures the secure installation of the certificate. The paragraph also touches upon the concept of asymmetric cryptography used by Apple for code signing, comparing it to a secure chat between two friends using public and private keys. The video concludes with an invitation for viewers to ask questions and a reminder to subscribe for future content.

Keywords

💡Provisioning Profiles

Provisioning profiles are digital entities that tie developers and their devices to an authorized iPhone development team, as per Apple's definition. They act as a link between the developer account and the devices, deciding which apps can run on which devices and what services they can access. In the video, it is explained that these profiles are necessary for the development and distribution of iOS applications, ensuring that only authorized devices can run the app during development.

💡Certificates

Certificates in the context of the video are digital documents that authenticate the identity of the developer and their app. They are used in conjunction with provisioning profiles to ensure the security and integrity of the code. The video emphasizes their role in code signing, which is a process that confirms the code has not been modified after it was signed, adding a layer of security similar to sealing an envelope with a stamp.

💡Code Signing

Code signing is the process of digitally signing the code of an application to ensure its integrity and security. It is compared to putting a stamp on an envelope to ensure the information inside has not been tampered with before it reaches its destination. In the video, code signing is crucial for the distribution of iOS apps, as it verifies that the app has not been altered and is safe to run on a device.

💡Development Certificates

Development certificates are a type of certificate mentioned in the video that authorizes test devices for running an app during the development phase. These certificates are part of the provisioning profile and are used to match against the certificate in the developer's keychain to code sign the app bundle. They ensure that only authorized devices can install and run the application under development.

💡Unique Device Identifiers

Unique device identifiers (UDIDs) are specific to each iOS device and are used within provisioning profiles to specify which devices are authorized to run an app during development. The video explains that these identifiers are checked against the device's UUID to verify its authenticity before the app can be installed, ensuring that the app is installed on intended devices only.

💡App ID

App ID is a two-part string that contains the team ID followed by the bundle identifier. It is used to identify whether a particular application is authorized to run on a device. In the video, the App ID in the provisioning profile is matched against the bundle identifier of the application being run; if they match, the application is allowed to install, otherwise, the installation fails.

💡Entitlements

Entitlements refer to the specific features and services that an app is authorized to use, such as app groups or push notifications. The video describes how entitlements are verified against the associated ones with the App ID during the installation process. They are part of the provisioning profile and define what capabilities the app is entitled to use.

💡Ad Hoc Distribution

Ad Hoc distribution is a method of distributing iOS applications to a larger audience for testing purposes, outside of the Apple Developer Beta Program. The video mentions ad hoc provisioning profiles, which allow apps to be tested on devices not listed in the developer certificates, providing a similar experience to the App Store build.

💡Asymmetric Cryptography

Asymmetric cryptography is a cryptographic system that uses a pair of keys, one public and one private. The video explains how Apple uses this system for code signing, where the public key encrypts the message (or code) and the private key decrypts it. This ensures that the code has not been tampered with, providing a secure way to verify the authenticity of the app.

💡Certificate Signing Request (CSR)

A Certificate Signing Request (CSR) is a block of encoded text that is generated when requesting a certificate from a Certificate Authority. In the video, it is mentioned that creating a CSR involves generating a public-private key pair, with the public key being embedded in the request sent to Apple. Upon approval, the certificate is matched with the private key on the developer's machine, ensuring a secure and authenticated process for obtaining developer certificates.

Highlights

Provisioning profiles and certificates are crucial for iOS app development, ensuring code integrity and security.

Code signing confirms that the source code hasn't been altered, enhancing security similar to a signed envelope.

A provisioning profile links a developer's account with devices, defining which apps can run on which devices and what services they can access.

Provisioning profiles contain development certificates, device identifiers, and the app ID, which are essential for app authorization and installation.

The installation process involves code signing with a developer certificate and checking device authenticity against the profile's UUIDs.

Development provisioning profiles are used for testing apps on specific devices during the development phase.

Distribution provisioning profiles are for app distribution on the App Store, allowing installation on any device after Apple's code signing.

Ad Hoc provisioning profiles facilitate app distribution to a larger audience outside of the Apple Developer Beta Program.

Code signing utilizes public-private key pairs and asymmetric cryptography to ensure the integrity of the source code.

Creating a Certificate Signing Request (CSR) generates a public-private key pair, with the public key sent to Apple for certificate issuance.

The certificate in the keychain matches the private key used for code signing with the public key provided by Apple, ensuring a secure process.

Understanding provisioning profiles and certificates is essential for iOS developers to avoid common code signing and provisioning errors.

The video provides a comprehensive guide for beginners to grasp the concepts of provisioning profiles and certificates in iOS development.

The presenter uses the analogy of an envelope with a signature to explain the concept of code signing in an accessible manner.

The video clarifies the purpose of different types of provisioning profiles and how they relate to the app development and distribution process.

Asymmetric cryptography plays a vital role in the code signing process, ensuring that the app hasn't been tampered with post-development.

The video offers practical insights into the iOS app development process, making it valuable for developers looking to understand the intricacies of code signing.

Transcripts

hey guys welcome to my channel icode

i am pallav and today we are going to

have a look at a very interesting topic

that is provisioning profiles and

certificates

i understand that as a beginner it's a

real pain it's very confusing to

understand that water provisioning

profiles what are certificates

why they are used what they do and how

they do

how our profiles link to certificates

those random errors of code signing

and everything else so today we will

deep dive into them

we will see that what is the use of

profiles

why they are used what is the use of

certificates how it is linked to

profiles

how they work in sync and everything

else so let's dive in

i believe that before understanding the

what part or how

part we must look at the why part as in

before understanding that what profiles

and certificates do

or how they do whatever they do we must

understand that why are they needed

so let's look at that first and then

we'll understand

that how they work so the first thing

that is why

and the answer is code signing code

signing is digitally signing of your

code

so whatever source code that you have

written for your application

the code signing gives us a confirmation

that after this point your code cannot

be modified

or in other words it just make it more

secure

so assume that you want to send some

sensitive information to your friend

you put that information in an envelope

and you cohere it to your friend

but you are afraid about its security

that it does not get compromised

the information do not get changed

before it is received and a simple way

to fix this

is to put a stamp to sign the envelope

to put your signature on it

so that whenever the envelope will be

received by the other party by your

friend

it will give a sense of confirmation a

sense of security that if the seal is

not broken

if your signature your stamp is not

broken it means that the information has

not been compromised

and the same thing is being done by code

signing

so your source code is digitally signed

to make it more secure

and this is done using provisioning

profiles and certificates

so now let's see that what is

provisioning profile

as per the apple's definition a

provisioning profile is a digital entity

that uniquely ties developers

and their devices to an authorized

iphone development team

and i understand that this is not very

clear so let's see it in detail

the first thing is that unlike android

iphone applications cannot run directly

on any device

those devices on which we target to test

our applications to run our applications

while development phase

those devices need to be signed by the

apple first or we say that those devices

need to be provisioned

now to do so provisioning profiles acts

as a link between the developer account

and the devices so with your developer

account whatever devices that you have

provisioned the provisioning profile

will act as a link between those two

provisioning profile decides that our

app can run on what all devices

and what all services it can access so

this relates to the entitlements part

that our app is entitled to use what all

features what are services like app

groups push notifications

everything else so before the ip

is made the profiles are downloaded from

the developer account

they are embedded in the bundle and then

the bundle is code signed

using certificates so assume that your

company your organization is sending you

to attend some conference

and the conference organizers want some

extra piece of information

to verify that you are the authorized

person who is here to attend the

conference

and what part of conference will you be

attending and

some other relevant information so along

with the other documents

your company will put an extra piece of

information having your employee id your

conference id or whatever information is

required by the organizers

that will help them identify that you

are the authorized person

and they will close the envelope they

will stamp it they will sign it

so that it gives a sense of security

that the information has not been

changed

and this extra piece of information that

they have put in the envelope

can be treated as provisioning profiles

now that we have an understanding of

what is a provisioning profile and what

it does

let's see that what does a provisioning

profile contains

so provisioning profile contain three

things development certificates

unique device identifiers and the app id

the development certificates authorizes

the test devices

that we want to run our app on the

unique device identifiers will let the

ios know

if this is the designated device on

which the app should run and the app id

helps in identify

that whether this particular application

is authorized to run on this device or

not

so app id is a two-part string which

contains the team id

followed by the bundle identifier so if

the app id that is in our provisioning

profile

if it contains the bundle identifier of

the application that we are trying to

run

if the two bundle ids match then it will

allow to install the application

otherwise the installation will fail

so provisioning profile contains these

three things the app id the certificates

and the device identifiers

now let's see that how does an app run

from the xcode

what actually happens when we hit

command r in rx code

how does the installation process take

place

once the build is done there are no

compilation errors there are a number of

checks that are made

the developer certificate that is

mentioned in our provisioning profile

is matched against the certificate that

we are having in our max keychain

if a match is found that certificate is

used to code sign our bundle

once the code signing happens the device

is checked for its authenticity

so the device on which we are trying to

run our application its uuid

is checked against the uui ids that are

mentioned in the provisioning profiles

if this goes well then the bundle

identifier of our application

is checked against the bundle identifier

mentioned in the app id

that is in the provisioning profile once

this is done then the entitlements

required by our

app are verified against the associated

ones with the app id

if all of these checks are done if

everything goes smooth

then the installation takes place

otherwise the app install

fails and at times you would have seen

that your app icon is greyed out

that is because one of these checks fail

or we can say that the installation

failed

so if you see your app id your

certificates the capabilities

the entitlements associated with your

app id and everything else can be

checked

in the signing and capabilities tab of

your export

now let's see that what are the types of

provisioning profiles

there's development ad hoc enterprise

and the distribution programming profile

now let's see the development first

development is the most

easy to understand provisioning profile

and we deal it with almost daily

as a part of our development process so

the development provisioning profile

contains the list of our test devices on

which we want to test our application

in our development phase and it cannot

be used for distributing

our application on test flight or on the

app store

the distribution profile does not

contain the identifier of any of our

devices

and it is used to distribute our app to

ship it on the app store

so if the distribution profile has been

used then the app can be installed on

any device

once apple code signs it and that

happens when we submit our app

to the app store the other two are used

in the development process

but at a later stage an add-on profile

is used to distribute our app to a

larger audience

the people who are not the part of the

apple developer beta program

or their devices are not mentioned in

our developer certificates

can test our app using the addock

profile

so an app that is deployed using ad hoc

provisioning profile is very identical

to the version that we submit on our app

store

as in the app store push notification

certificate is used with the adult

provisioning profiles

and it gives the almost same experience

as that of the app store build

now let's see that how code signing

works because we have been discussing

about the code signing since the start

of the video

now let's see that how it is done

so one thing that we know is that code

signing gives us a sense of confidence a

sense

of trust that our source code has not

been modified

since we have signed it now this is done

using a public private key pair

that apple has created for us or we can

say

that apple uses asymmetric cryptography

for this purpose

let's understand it

sam and john are two friends and they

decide to encrypt their chat

to do so they came with the concept of

public and private key

both of them made a pair of keys that is

public and private key

sam gave his public key to jon and john

gave his public key to sam

now when sam needs to send a message to

john he encrypts the message using

john's public key when john will receive

the encrypted message he will decrypt it

using his private key

same will be done by john he will

decrypt the message using sam's public

key and when sam will receive it he will

decrypt it using his private

key this concept is called the symmetric

trip

so this is the concept of asymmetric

cryptography that apple uses

for signing our code when we request a

certificate from the certificate signing

authority or that we create the csr that

will see it in a moment

the same thing happens the public key

and the private key pair is used for

signing our code

let's see certificate signing request

to get the developer certificate from

the apple we need to create a

certificate signing request

through our keychain when we create the

certificate signing request

a public private key pair is created on

our machine

and the public key is embedded in that

request that we send to apple

so basically certificate signing request

is a block of encoded text

that is having our public key that has

been generated from our machine

after the apple proof the request and we

get the certificate

when we double click the certificate to

install it in the keychain

it is matched against the private key

that was generated at the time of

certificate signing request

so when we created the csr or

certificate signing request

we created a pair of public key and the

private key the public key was

embedded in the certificate signing

request using which the apple created

the certificate

and now when we are trying to install

that certificate it is matched against

the private key that we are having in

our machine

if the match succeeds then the

certificates will be installed

otherwise it will not

now the certificate that we are having

in our keychain it also has a public key

given by apple

so at the time of installation the

private key that is used to sign the

bundle

is matched against the public key in the

certificate

if the match succeeds the installation

happens otherwise it fails so this is

the whole idea behind the code signing

the public private key or the asymmetric

cryptography that is used by apple for

this purpose

so i hope that you have got the concept

of provisioning profiles and

certificates

like why they are used what they do and

how they do

why do we get the errors for code

signing for provisioning profiles

identify or not match etc etc and if

there are any other doubts please put

them in the comments and i'll try to

answer them

so that's pretty much for this video a

new video comes out every sunday

so do subscribe to my channel let's

write better code together

happy coding and stay safe