Certificate Pinning | Types, Risks & How to Implement

Certificate Pinning | Types, Risks & How to Implement
8 min read


Are you concerned about the security of your mobile app's communication channels? If so, you're not alone. With cyber threats becoming more sophisticated than ever before, it's important to take every possible measure to protect sensitive user data. One such measure that has gained popularity over the years is certificate pinning. So, whether you're a developer or just someone interested in tech security trends, keep reading to learn all about certificate pinning!

What is Certificate Pinning?

Certificate pinning is a security technique that helps to protect against man-in-the-middle (MITM) attacks by ensuring that the client only communicates with an explicitly trusted server. This process involves embedding a public key or certificate within the application code, which allows it to verify whether the SSL/TLS connection is valid.

At its core, certificate pinning relies on two types of pins: trusted and anticipated. Trusted pins are pre-configured into the app and represent known good certificates for specific domains or servers. Anticipated pins, on the other hand, are dynamically generated during runtime and serve as additional validation checks.

By implementing certificate pinning in your app or website, you can add another layer of protection against hackers who may try to intercept traffic from your users' devices. While some argue that this technique has limitations and potential downsides, it remains a valuable tool for enhancing overall security posture.

The Different Types of Certificate Pinning

There are different types of certificate pinning that can be implemented to secure mobile applications. The first type is Static Pinning, which involves hardcoding a set of public keys into the application's codebase. This method guarantees that only certificates with those specific keys can authenticate requests.

Another type is Public Key Pinning Extension for HTTP (HPKP), which allows server administrators to specify a list of hashes of their website's authentic public key(s). When clients connect, they receive this list and verify it against the site's public key before completing any further transaction.

Certificate Authority (CA) Pinning is another form where instead of pinning a particular certificate or public key, an app pins its trust on a specific CA. By doing this, the app will only accept digital certificates issued by that trusted CA.

There is Hybrid Certificate Pinning – combining static and dynamic methods - where apps use both HPKP and either static or CA pinning to ensure maximum security.

Each method has its advantages and disadvantages; it's important for mobile developers to choose the appropriate one based on the application’s specific needs.

Pros and Cons of Certificate Pinning

Pros and Cons of Certificate Pinning

Certificate pinning is an effective way to secure your website or mobile application by verifying the authenticity of SSL certificates. However, like any technology, there are pros and cons that come with implementing it.

One benefit of certificate pinning is increased security. By ensuring only specific trusted certificates can be used on a server, certificate pinning reduces the risk of Man-in-the-Middle attacks where hackers attempt to intercept communication between client and server.

Another advantage is improved performance as it eliminates extra time needed for certificate chain verification by relying solely on pinned certifications.

On the other hand, one disadvantage is that if something goes wrong with a pinned certificate - such as expiration or revocation - users may not be able to access your site or app until you update its pins.

In addition, misconfiguration could lead to a false sense of security which can result in developers not performing timely updates or using unapproved certificates leading eventually to vulnerabilities.

While certificate pinning offers benefits in terms of enhanced security and performance improvements over traditional SSL/TLS approaches ,it's important for organizations considering this approach weigh its advantages against potential drawbacks before implementation.

How to Implement Certificate Pinning?

Implementing certificate pinning can be a technical process but with careful planning and execution, it can significantly improve the security of your application. Here are some steps to take when implementing certificate pinning.

Identify the domains or endpoints that you want to apply certificate pinning to. This could include APIs, backend servers or third-party services that your application interacts with.

Next, generate a hash for each SSL/TLS public key that corresponds to these domains/endpoints using tools such as OpenSSL or KeyChain Access on macOS. Once you have generated these hashes, hard-code them into your mobile app's codebase.

It's important to keep in mind that SSL/TLS certificates expire after a certain duration. As such, it's essential to monitor and update these pinned certificates regularly.

Thoroughly test your implementation before deploying it in production environments. Ensure all edge cases are covered and consider any potential impact on user experience or performance issues.

While implementing certificate pinning requires effort upfront, It provides an extra layer of protection against man-in-the-middle attacks and ensures only trusted servers are accessed by your application.

Alternatives to Certificate Pinning

While certificate pinning is an effective security measure for protecting against man-in-the-middle attacks, it may not always be the best option for every situation. There are several alternatives to certificate pinning that can provide similar levels of protection.

One alternative is to use public key pinning (PKP), which involves only trusting specific public keys rather than entire certificates. This allows for more flexibility and easier management compared to certificate pinning.

Another option is to use HTTP public key pinning (HPKP), which involves adding a header to HTTP responses that specifies which public keys are trusted. While HPKP has its own set of risks and challenges, it can still be a useful alternative in certain scenarios.

Using Transport Layer Security (TLS) with proper configuration and implementation can also provide strong security measures without requiring the complexities of certificate or public key pinning.

While certificate pinning remains a valuable tool in securing applications and data, there are other options available depending on individual needs and circumstances.


Certificate pinning is a powerful tool that can enhance the security of your app by preventing man-in-the-middle attacks. It allows you to specify which CA certificates are trusted for your application, ensuring that only those certificates will be accepted by the client. However, it's important to weigh the pros and cons of this approach before implementing it in your project.

While certificate pinning can provide additional security benefits, there are also some downsides to consider. For one thing, it can make updates more difficult since new pins may need to be added as part of any changes made. Additionally, if a pinned certificate expires or is revoked, users may have difficulty accessing your app until you update the pin with a new certificate.

Certificate pinning is just one option when it comes to securing communication between clients and servers. Whether or not you decide to use it will depend on many factors such as your specific needs and resources available for implementation.

Ultimately though, no matter what method you choose for securing communication in your mobile app development process – whether through SSL Pinning Android or Certificate Pinning Android – remember that security should always remain top priority throughout every step of development!


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Nita Singh 2
Joined: 1 year ago
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