Beginner’s Guide To SSL Pinning In IOS And Android Apps

Beginner’s Guide To SSL Pinning In IOS And Android Apps

The rise of mobile banking apps has enabled users to enjoy their banking services from the comfort of their homes. However, the increase in cyber attacks among a growing number of online enterprises has posed serious concerns for online shoppers who need to share their financial details across such networks using their mobile devices. Nowadays, hackers are using sophisticated means for accessing information where Man-In-The-Middle attacks can result in financial loss and affect the credibility of online businesses. SSL pinning can be an effective mechanism to prevent such advanced hacking threats.

  • SSL and importance of SSL pinning

SSL and importance of SSL pinning


Secure Socket Layer (SSL) helps to encrypt client server communication across HTTPS to make the process of data transmission safe and secure across networks. For this purpose, organizations may use different types of SSL certificates to meet their specific business needs. If you have multiple websites with multiple versions across geographical locations, it makes perfect sense to have SSL certificates. Almost 100 different domains and subdomains may be protected using this kind of certificate.

SSL encryption is a safe and secure method to protect your website from hacking attempts, but it may prove to be ineffective against man in the middle attacks. Now, this is where SSL pinning comes into play in building extremely secure mobile apps for users accessing multiple wireless networks through their mobile devices. SSL pinning is a mechanism that helps to boost the security of sites and services that rely on SSL certificates. When a mobile app connects with a server, the app uses its implemented SSL certificate and trusts that only server that has certificate trusted by operating system’s store. Thus, SSL pinning in an Android app is easy but ensuring that the connection is safe is more important.

  • Key benefits of SSL pinning for Android devices

Confirms validity and legitimacy

SSL certificate pinning also known as public key pinning helps to reduce over dependence on third parties while making security decisions that has an impact on identities. This is because most third-party apps do not adhere to security protocols although some developers follow them strictly. The app download and the process of installation may be still open for hackers as they try to remove the certificate or replaces it leading to MITM attacks.

Certificate pinning plays a key role as the app depends on its stored certificate without trusting on the license of the device’s trust store.

Improved security

SSL certificate pinning allows your Android banking app to be more independent while reducing its reliance on the trusted store of the device. This may make it challenging for intruders to compromise on the code which may require decompiling, changing, and recompiling the app. Interestingly, SSL certificate pinning helps to allow reliable certificates on the mobile app and dismisses unknown requests coming from suspicious servers.

Prevents leakage of information

SSL pinning discourages communication with servers that offer self-signed certificates for different hostnames. In addition, both hostname validation and certificate validation are done to prevent MITM attacks. Thus, it is difficult to trick users in installing compromised certificates as pinning does not allow for data transmission and helps in keeping the information secure while decreasing the chances of information leakage.

  • Implementation of SSL certificates pinning

Implementation of SSL certificates pinning

There are two options for pinning SSL certificates which you can choose by downloading the server certificate and bundling them in the app. During runtime, the app makes a comparison between the server certificate along with those which are already embedded. Otherwise, you have another option of retrieving the public key of the certificate in the code in the form of a string. Thus, in the runtime, the application will compare the public key of the certificate with the one which provided in the code.

Choosing among these two options depends entirely on your individual and server configuration needs. Similarly, there are many popular options available for performing SSL pinning in IOS devices ranging from URLSession, TrustKit, AFNetworkingand AlamoFire. For Android, there is a new technique that developers use by including hashes of public and backup keys in network_security_config.xml file.

Vice versa certificate pinning in iOS requires Trustkit library that is used also for Android. Below is code for iOS certificate pinning.

iOS requires Trustkit

These are the three different ways of implementing SSL pinning on Android apps:

  • TrustManager

TrustManager is a component which is used to decide if the app needs to accept the credentials provided by the peer or not. The mechanism is sourced using the package which may be used to implement certificate pinning in Android apps.

  • oKHttp and Certificate Pinner

okHttp uses a mechanism which makes certificate pinning extremely easy and efficient by creating an instance of CertificatePinner using a dedicated builder with the help of corresponding fingerprints.

  • Network Security Configuration

Network Security Configuration may be used for implementing the pinning process and this method provides a simple way of network configuration. With NSC, users may be able to use XML files by adding certificate pinning into their configuration with fingerprints.


SSL pinning in Android apps and iOS apps is one of the best ways to prevent man-in-the-middle-attacks and fix security loopholes to ensure greater user safety and protection of their personal information online while instilling trust and confidence among them.

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