Certificate pinning and Public key pinning in Kotlin

Needone App
2 min readFeb 24, 2023


With the last article ( Certificate pinning and Public key pinning), we know the concept of Certificate pinning and Public key pinning, and how to implement them in iOS. This article will demonstrate how to implement them in Kotlin.

Implement certificate pinning

Certificate pinning is a security technique that involves associating a specific certificate or public key with a particular server. This helps to prevent man-in-the-middle attacks by ensuring that the client only trusts the specific certificate or public key associated with the server, and not any other certificate that may be presented by an attacker.

Here is an example of how to implement certificate pinning in Kotlin using the OkHttp library:

Implement public key pinning

val certificatePinner = CertificatePinner.Builder()
.add("example.com", "sha256/1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ")

val client = OkHttpClient.Builder()

val request = Request.Builder()


In this example, we create a CertificatePinner object using the CertificatePinner.Builder class. We add a pin for the example.com domain using the add method, specifying the domain name and the SHA-256 hash of the public key.

Next, we create an OkHttpClient object using the OkHttpClient.Builder class and set the CertificatePinner object using the certificatePinner method.

Finally, we create a Request object using the Request.Builder class and specify the URL of the server. We use the OkHttpClient object to send the request and execute it.

Originally published at https://needone.app on February 24, 2023.

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