How to disable ssl pinning android programmatically. You need to make your app run as device owner.

How to disable ssl pinning android programmatically. Enable the Disable Certificate Validation setting.

How to disable ssl pinning android programmatically. txt -f owasp. addSslPinningErrorListener(callback: ErrorListenerCallback): EmitterSubscription: Subscribes to SSL pinning errors due to pin mismatch. Jun 7, 2023 · Within the Objection console, execute the following command to disable SSL pinning for the specified application. SSL pinning is a technique to prevent MITM attacks by binding a specific SSL/TLS certificate to a particular server or service. Dec 26, 2023 · There are a few ways to disable screen lock in Android programmatically. bks files stored in app raw folder. Server will verify these details and send confirmation PIN on user mobile (got this MSISDN in user details). xml file on the Android manifest (we already did this in the previous step) add the TruskKit dependency to the build. Copy the server certificate file (e. Jun 5, 2023 · Step 2: Adding the Certificate to the Project: To use the server certificate for SSL pinning, we need to add it to the Android project. com , trust it only if the public key is SHA256/AAA . Follow these steps: Create a directory named ‘raw’ in the ‘res’ folder of your Android project. . so) seems to comprise the Flutter engine that is compiled (AOT). In other words, you configure the app to reject all but one or a few predefined certificates or public keys. This post shows the steps to patch the binary to bypass ssl pinning on Android apps (armeabi-v7a). If you choose public keys, you have two additional choices: (a) pin the subjectPublicKeyInfo; or (b) pin one of the concrete types such as RSAPublicKey or DSAPublicKey. pin-code. jsscript onto the device, copy it to the adb folder and run the following command: Sep 4, 2018 · Android SSL Certificate pinning. Reactions:tosunkaya, MiguexD, Alec Chanand 4 others. There is no sense in implementing dynamic key or cert. 1 or above. sh admokonugroho. Again, to confirm whether SSL pinning has been bypassed, click on CERTIFICATE PINNING, and you should now be able to capture the request. I am building a flutter web app and I need to use SSL to talk to the server using a . A man-in-the-middle attack can be carried out using several methods including ARP cache poisoning and DNS spoofing. 509 certificate. Rooting/Jailbreaking: Jan 9, 2018 · In this blog I’ll go through 4 techniques you can use to bypass SSL certificate checks on Android: Adding a custom CA to the trusted certificate store. Lock task / screen pinning. Without pinning you can use things like mitmproxy Feb 1, 2021 · SSL (Secure socket layer) Certificate Pinning, or pinning for short, is the process of associating a host with its certificate or public key. medium. , server. I am using web services Request and response using XML protocol. Mar 16, 2021 · To obtain the pin for the host we are talking to we will use SSL Labs. Open “Network Layer Initializes and enables SSL public key pinning for the domains and options you specify. I think there are some solutions: Anti repack your apk: because if a hacker want to bypass SSL pinning, he have to repack your apk using apktool. Install the SSLKillSwitch package. gradle file: Step 2: Create a Certificate Pinning Helper class. Adding the API domain (s) only needs to be done one time and should be done before you register your first mobile app APK. I think this can be done by just getting public key or cert file from one of the api just like we have api to get json data or a file download. js. Retrofit offers you an extremely convenient way of creating and managing network requests. Include Required Dependencies: In your app’s build. You will see the certificates listed; each certificate has an Additional Certificate — which is a backup. During this period the app is exposed, but it continues to work!! The code: public abstract class CertificatePinnerManager {. NoConnectionError: javax. Mar 10, 2019 · An Xposed module to disable SSL verification and pinning on Android using the excellent technique provided by Mattia Vinci. GitHub repository| Xposed repository. I have successfully implemented for SSL Certificate Pinning for my Android Studio developed Application. java, paste in the content of this commit. py <your . In Request handling tab, enable Support invisible proxying and click on OK. 2-When I pass incorrect sha-256 pin to certificate pinner then it throws exception com. </application>. Install Frida on your computer. sh. You can refer to this Medium blog which explains the implementation of SSL Pinning using different network libraries such as OkHttp, Volley, Retrofit etc. Update 1: Ensure you are using okhttp with version 4. For doing ssl pinning bypass, we can use the command android sslpinning disable. apk. Installed the target app. pem file> Sep 27, 2021 · بسم الله الرحمن الرحيم. copy. httptoolkit. On Appdome, follow these 3 simple steps to create self-defending Android Apps that Block SSL Pinning Bypass without an SDK or gateway: Upload the Mobile App to Appdome. An attacker can find the function, which determines whether a certificste should be trusted or not, and patch it in memory to always return true. answered Jan 13, 2021 at 4:13. Your app will also be more Oct 17, 2019 · I am developing a project that require the Android app can prevent bypassing certificate pinning/trust a fake cert when doing network calling even in a rooted devices. 5. OWASP defines SSL pinning as “Users and developers expect end-to-end security when sending and receiving data in their applications, especially sensitive data on channels protected Sep 10, 2015 · 3. java. Pinning through android:networkSecurityConfig. Nov 14, 2015 · Now I want to register user using this HTTPS connection. But I can't find documentation on that anywhere. I know very little about SSL/TLS let alone pinning. Pinning app will lock user into your app and user will not be able to leave the app unless they press and hold back and overview buttons together (triangle and square buttons). To clarify the pinning part of it, this is what one needs to do. How to implement SSL Certificate Pinning in Native Layer Android programmatically. if your certificate is valid then only your request will proceed. 6. Analyze the responsible method and map the same with the SMALI code. At a high level, you need to: Connect ADB to a rooted device or emulator. io. In the same folder as your Android app’s MainApplication. CertificatePinner, overriding CertificatePinner. Create a new Kotlin class in your project, e. change the VolleyQueueSingleton class to use Feb 11, 2023 · Binary patching involves modifying the binary code of the application to disable SSL Pinning. This is an api of device owner. disableSslPinning(): Promise<void> Disables SSL public key pinning. gradle file. The point of (proper) SSL pinning is that the app expects a specific certificate. User will enter this PIN and server will verify that PIN is same. See full list on joncooperworks. Override the checkServerTrusted. net server certificate, you would add individual entries as items in an array to the Info. openConnection("https://. twitter. Jul 4, 2021 · A binary dubbed libflutter. Begin exploring the app on your iOS device and notice how the traffic is captured by the Burp Suite. java -jar uber-apk-signer-1. agoat -U. This will just hide the app not disable or uninstall this. This will remove the SSL pinning mechanism from the Oct 9, 2019 · 2. These are the results and take the seconds item because that is the server certificate. If you are behind a corporate firewall which does SSL interception you should install the proxy CA used for SSL interception as trusted. However, I want to disable it. android. 1 . You can do that by check your apk signature, if not match, exit your app. Summary. Nov 8, 2023 · Step 6: Bypass SSL Pinning. js” script into device. You need to make your app run as device owner. Load Jan 13, 2020 · I can make an app lock as long as I set the device owner with an EMM or adb commands. xml file (we already did this in the previous step) load the network_security_config. Dio library provide a call back on badCertificateCallback when it find some self signed certificate in between the connection. Jan 3, 2024 · Steps to Bypass SSL Pinning with Proxy Droid. The Network Security Configuration feature lets you customize your app's network security settings in a safe, declarative configuration file without modifying app code. i need it for academic purposes. Download Proxy Droid: Proxy Droid can be easily found on the Play Store, but it’s important to note that the app requires a rooted Android device to May 23, 2017 · If you setup SSL interception with tools like mitmproxy or Burp and then import the proxy CA of this interception proxy into the android certificate store as trusted then you should be able to intercept the connection, i. Android allows applications to perform SSL pinning by using the network_security_config. tech. NOTE: we need to turn off all the proxies because reflutter is already modifed and set the proxy settings in the patched app. 4- we are Nov 19, 2020 · Note that some applications have multiple ways to pin a specific domain, and you may have to combine scripts in order to disable all of the SSL pinning. Downloaded the Frida server for my Device architecture. SSLSocketFactory {. Just put your self signed certificate fingerprint in the call below: await SslPinningPlugin. SSL pinning involves embedding a public key, hash, or certificate directly into your code, ensuring that only requests signed with trusted certificates are accepted. From asynchronous execution on a background thread, to automatic conversion of server responses to Java objects, Retrofit does almost everything for you. android -l sslpinning. 2. Add the OkHttp dependency to your app-level build. init() (agent) Found okhttp3. basic Auth. Dec 14, 2017 · Is there any way to programmatically query the system settings for screen pinning, i. To disable screen lock using the `KeyguardManager`, you can use the following code: java Jun 25, 2023 · Bypass SSL Pinning. Step 1: Run the frida server on android device. $ python get_pin_from_certificate. There are couple of ways that you can try out to make secure your apps: Certificate Pinning. For example, if the domain name starts with *. pem file. java file, create a new Java file and name it SSLPinnerFactory. Certificate Pining : Obtain a certificate from your server and attach it to your each HTTP request. Network security configuration. For certificate pinning, your ensuring you get the expected server certificate. How it happens depends on whether the application is white listed by a device owner app (possibly itself) : If not, the user is prompted and must accept, they can also exit at any time. The following are two of the most common methods: Using the `KeyguardManager` class: The `KeyguardManager` class provides methods for managing the screen lock on Android devices. Aug 10, 2014 · 3. This article discusses best practices related to secure network protocol best practices and Public-Key Infrastructure (PKI) (PKI) considerations. It will show a prompt, you can simply follow it. -keepclassmembers class * implements javax. Sent the Frida Server to its path in Device. This is basically the same thing as screen pinning. The connection is then validated via X509TrustManager. whether it is turned on and whether a pin is required for unpinning apps? Background: I would like to implement a Kiosk app which ensures that leaving the screen pinning mode requires entering the device PIN. Rooted my Android Device. Jan 12, 2021 · Hopefully after i overrode the class name, method name and object name of OkHttp3 would able to prevent man-in-the-middle attackers to bypass certificate pinning by using Okhttp3. check() (agent) Found okhttp3. Once you know a host’s certificate or public key, you pin it to that host. I am using HttpClient and IOClient to get it to work and the code for this looks as following: HttpClient _client = HttpClient(context: await globalContext); _client. Sign the application with uber apk signer via the following command. Dec 12, 2023 · This is more difficult with SSL pinning in place, but sophisticated attackers may attempt to inject code to disable or bypass SSL pinning checks. URL. The typical Android solution is to bundle the hash of the certificate, or the exact data of the certificate into the application. That is the key concept of asymmetric cryptography. crt and . We are taking an Android application in our scenario, if you have the device rooted then you can use Jun 23, 2022 · Search for the “SSLKillSwitch” in Cydia. xml file. make sha256. return null. The option is in 'Settings' -> 'Security' -> 'Set up SIM card lock'. It looks like you used to be able to start screen pinning (not Kiosk or Single App Mode - just regular screen pinning) programmatically with setLockTaskEnabled() without being Device Owner. With the script at hand, you can run the next command: frida -U -f com. Using JustTrustMe - Xposed Apr 21, 2016 · this is for device owner not for possible to use this if your application is only device admin. Step 3: Configuring SSL Pinning Nov 19, 2020 · OkHttp for Android: Option to NOT enforce Certificate/ public key pinning 4 Certificate Pinning in OkHttp vs Android Network Security Config Oct 25, 2016 · I need to implement SSL Certificate Pinning in my react native application. /sha256. But this has a security issue can intruders can use save api end to get same credentials and bypass ssl pinning you have implemented. 1. Nov 22, 2023 · Network security configuration. so that, the user cannot be able to see the traffic? (assume the user phone is rooted) certificates. Is there a way to prevent the bypass of SSL certificate in android. This is the second part of my 2 part blog series on mobile app pen-testing and reverse engineering. I just need to prevent some bypassing method like using JustTrustMe in Xposed framework. Using Frida to hook and bypass SSL certificate checks. Feb 7, 2020 · 9. Aug 26, 2014 · The exception I'm being given is: javax. Overwriting a packaged CA cert with a custom CA cert. Learn more about it here. X509TrustManager({. Jun 23, 2023 · Step 1: Create a Network Security Configuration XML File. Jun 26, 2019 · In order to add TrustKit into a mobile app we need to: add a network_security_config. You should never see this. Jul 30, 2019 · Nowadays for Android a simpler way exists, and I describe it in my blog post Securing HTTPS With Certificate Pinning, where you can learn that it can be done just by adding the certificate pin to the network security config file, or if you need to support below API level 24, then you may want to use the TrustKit package in conjunction with the Apr 24, 2015 · To add SSL pinning in a Kotlin Android app, follow these step-by-step instructions: Step 1: Add the OkHttp library to your project. Jan 24, 2018 · 1. com for the Hostname field and click Submit. Once the installation is complete, run the application and initiate Objection with the following command to bypass SSL pinning: objection explore android sslpinning disable. You will see frida doing it’s thing: And the twitter application is ran on the device. Jul 13, 2018 · You can use SSL Pinning Plugin to do this. Oct 8, 2022 · You cannot prevent someone from bypassing SSL pinning. The following code produces an SSLContext which works like a charm in creating an SSLSocketFactory that doesn't throw any exceptions: This guide will walk you through SSL Pinning basics, how it’s implemented, and various tools and methods to bypass such protection in the Android Apps. get_pin_from_certificate. No other CA from the Zoo can claim to certify your site. net. 22. sh + admokonugroho. Once the responsible method is analyzed and identified, we can use the You signed in with another tab or window. @Robert frida ssl unpinnning script doesn't work on all apps, so i am looking for a sample app which works with this framework. The effect is system-wide. Feb 5, 2024 · 1. com. Have started the Frida Server. Each entry has a Pin SHA256 value. You can store the Sep 20, 2022 · Using the network_security_config. Create a new file Jan 20, 2022 · 12 echo -e "" 13 done. gradle file, add the dependencies for Retrofit and OkHttp (an HTTP Nov 29, 2022 · If the certificate is expired, the app does not use certificate pinning. Pin the CA's or server's certificate with a custom TrustManager. sh as executable file: 1 chmod +x . Retrofit with custom Apr 14, 2022 · In my last video, I bypassed SSL Pinning on an Android device using Frida, which required a rooted device. If you need that, foreground services are the way to go. Jan 13, 2017 · 2. Go to the project’s res directory, create an XML folder, and create the file network_security_config. sim-card. agoat’ with your target package name to run the command: frida -l sslby. Certificate pinning is a good way to prevent man-in-the-middle attacks. And there you have it, a guide to bypassing SSL pinning in Android apps using Frida For this choice, you have two options: you can (1) pin the certificate; or (2) pin the public key. approov. 509 certificate with the PKIX algorith Though this process is tedious and complex, the pinning SSL certificate is worth the effort as it decreases the risk of data leaks and serves as countermeasures against MITM attacks. Move your code of SSL pining to NDK and build . That’s it, the script will find the SSL pinning classes and hook them during the runtime in order to bypass the SSL pinning. Feb 22, 2016 · In case someone is looking to disable SSL certificate checking in a NativeScript Android app, here's how to convert Elad's answer's code to JavaScript: const disableSSLCertificateCheckin = function () {. Token Based Authentication. google, facebook works well The easy way to implement this is to use this attribute to your AndroidManifest. getAcceptedIssuers: function () {. TrustStore and sslSocketFactory. Jan 3, 2024 · Android 11. Once you've done this the browsers will disable certificate pinning as long as the certificate is signed by this explicitly trusted CA. This post explains what SSL pinning is, its benefits, and provides a step-by-step guide on implementing SSL pinning in a React Native app for both iOS and Android. I have done for Java layer ssl pinning in my application,for this pinning purpose, I have used two certificates . plist file of your app. Aug 2, 2018 · 0. If it is for academic purposes I would search GitHub of sample Mar 26, 2020 · Anyway for iOS, we are using TrustKit for the SSL Pinning. SSL Pinning, or pinning for short, is the process of associating a host with its certificate or public key. OKHTTP with certificatePinner. Security researchers or Jan 4, 2021 · SSL Pinning comes to rescue By providing the “true” server public key information, you can restrict the application to only trust the provided public keys for certain domain names. That the yearly HTTPS certificate renewal is a problem for implementing leaf certificate pinning is true. In this repository there is an inbuilt script(i. check(serverURL: url, headerHttp : new Map(), allowedSHA1Fingerprint: new List<String>, timeout : 50); The call returns: On success, return String "CONNECTION_SECURE". You need to add the following to the proguard file inorder to avoid crash on Android 10. Nov 17, 2019 · Installed the Frida library and Frida-tools. through java. ssl. This is because the verification is done on a device, which the attacker controls. 88 1 10. The end goal is to have the client accept your own Nov 13, 2022 · 1. Upload Method: Appdome Console or DEV-API. When I add the ceritificates as a Server. pem certificate. sat. In Android how do I disable SIM card PIN code programmatically? Many other posts ask how to unlock/set/reset SIM card PIN code. Getting the public key is useless as you can not use it in a HTTPS handshake without knowing the private key. xml where you allow all http for all requests: <application android:usesCleartextTraffic="true">. pinning_demo on (xiaomi: 10) [usb] # android sslpinning disable (agent) Custom TrustManager ready, overriding SSLContext. Using SSL in an Android app is easy, however ensuring that the connection is actually secure is a different matter. For CA pinning, you're removing the CA Zoo and only using the one true CA. Note that if it worked with NetCapture then it did not use SSL pinning - it just used SSL without pinning. J. private final javax. burp-suite. These settings can be configured for specific domains and for a specific app. ")) the JSSE implementation of the SSL protocol performs few validations to ensure the requested host is not fake. Enable the Disable Certificate Validation setting. Jun 8, 2016 · Once you get that email, open it from your Android device and download it. If it was successfully installed, you can see that certificate in your device's "Settings-> Trusted Credentials ->User" section. 3. Jul 16, 2009 · By design when we open an SSL connection in Java (e. Read Android Security Overview as well as Permissions Overview for more details. Now open the new apk and click on HTTPS Request. Rooting is the process of gaining administrative privileges, often referred to as “root access” or “superuser access,” on an Android device. Dec 20, 2019 · Certificate pinning is the mechanism of associating a domain name with an expected SSL/TLS certificate, technically and more accurately known as an X. Therefore it is impossible to simply use a different certificate - no matter if self-signed or not. so lib to use, hacker may be harder to modify . Sep 1, 2023 · Custom TrustManager. SSLSocketFactory delegate; } Dec 5, 2023 · Block SSL Pinning Bypass on Android apps using Appdome. Whenever the user clicks on a link, the device needs to establish a connection with the server hosting that domain name, and for this to happen, a TLS handshake takes place in Apr 20, 2022 · 5) Injecting Script to Bypass SSL Pinning. so seems to contain the dependencies responsible for establishing remote connections. 3. Now go to Settings > SSL Kill Switch 2. This binary (libflutter. SSLException: SSL handshake terminated: ssl=0x74b522b0: SSL_ERROR_ZERO_RETURN occurred. Taint Analysis using Frida. CertificatePinner Aug 18, 2023 · To implement SSL pinning using Retrofit and Kotlin, follow these steps: 1. Create an OkHttpClientFactory with SSL Pinning. This method requires the use of a disassembler and a hex editor, and can be time-consuming and complex Nov 30, 2022 · HOW TO HACKhow to hackAndroid hackingAndroid testingSSL PINNGDisable SSL Pinning #cybersecurity #hackingtutorial #androidhacking 0:00 intro0:12 Disable SSL i Nov 5, 2023 · Replace ‘owasp. example. g. I am also not a native mobile developer, though I know Java and learned Objective-C on this project enough to get around. This is how you do it: Multiple fingerprints can be added for various domains. I suppose you have already apps installed that use pinning: Google Play Store respectively Play Services. In order to disable the promise, we want to decompile the application file and find the method bound for pinning control and remove the check. android. We are using the fridascript. The three choices are explained below in more detail. Step 1) Push the “fridascript. Oct 18, 2022 · The next step is to use the CertificatePinner to create an OkHttpClient instance. 1. In this tutorial, I will try to discuss step-by-step SSL Pinning Bypass using NoxPlayer as an emulator, nox_adb, frida, and Objection on Windows Jan 14, 2021 · To introduce redundancy into your pinning configuration, you can associate multiple public keys with a domain name. crt) into the 'raw' folder. You switched accounts on another tab or window. java. jar — apk test. Jan 31, 2022 · 1 2. e. In this way, the app is "exposed with no certificate pinning" between the certificate expiration date and app update (with new certificate hashcode). Doesn't React Native already implement this? Oct 15, 2019 · First, you start by letting Approov know what API domain (s) you want to protect with Approov, and this is easily done via the Approov CLI with: approov api -add currency-converter. paulsenjs. Got the Frida Script File ready. const trustAllCerts = [new javax. Client-server encrypted interactions use Transport Layer Security (TLS) to protect your app's data. Type your-domain. For example, to pin multiple public keys for the example. So far I can make it when the device is not rooted. xml file in the XML folder we can achieve pinning. SSLPeerUnverifiedException: Certificate pinning failure! 3- when I pass the correct pin it works request gets success. Finally, execute the file sha256. Start browsing the application and Feb 1, 2022 · 5 SSL Pinning bypass. This involves validation of the server's X. Theft Detection. Then select the downloaded certificate to install it. Useful for various security audits. volley. Nov 13, 2018 · We will first see to use this script to bypass SSL Pinning and then we will analyze what the script does. Reversing custom certificate code. Install and start Frida on the device/emulator. Jan 2, 2024 · The SSL pinning (or public key, or certificate pinning ) is a technique mitigating Man-in-the-middle attacks against the secure HTTPS communication. May 29, 2020 · Here I will discuss four ways we can achieve SSL pinning in Android apps. Yes piyush is right. The ebook covers offensive and defensive side of SSL Pinning and includes the following: Lower Android Version. badCertificateCallback =. Sep 19, 2016 · 1. To push the fridascript. The key capabilities of this feature are: Jun 16, 2019 · In order to disable the promise, we want to decompile the application file and find the method bound for pinning control and remove the check. Let's walk through how to do that in practice: Jul 24, 2015 · A brief overview of SSL and HTTPS on Android is covered here. 2. But in case you want some more configurations for different links for instance, allowing http for some domains but not other domains you must provide Oct 25, 2019 · thanks a lot. Upload an app to Appdome’s Mobile App Security Build System. You signed out in another tab or window. Certificate chain for appmattus. com May 2, 2019 · There are a few methods by which a user can bypass the pinned SSL certificate of an android application by using tools like Frida, Objection, etc. get the plain text. 0 SSL Pinning Certificate. On the next page select one of the servers. In the first Jul 20, 2020 · Description. Yes, there is a way, but: This is not a way to prevent OS from killing your app process. Objection -g <package name/PID> explore. android sslpinning disable. py) to get the public key sha256 hash from the . sslstrip. Now you’ll be able to capture requests from the Twitter application, confirming that your SSL pinning bypass is working! May 22, 2020 · 1-We are able to intercept request/response in the burp suite tool for API <=23. SSL pinning allows the application to only trust a valid or pre-defined certificate or Public Key. Granted the Frida server the necessary permissions. so file to bypass. Core to SSL (Secure Socket Layer) is the X509 certificate, and Jul 24, 2018 · Understand the implementation of SSL Pinning. To implement SSL pinning using XML, start by creating a network security configuration XML file in your Android project. Nov 9, 2021 · SSL Pinning is not a default behaviour of flutter but Dio library do reject self signed certificate that we install, when using proxy server in order to intercept API Calls. Have you find Sep 14, 2017 · All modern Android apps need to do network requests. com (domain) then, you will get the public keys. 7K. The process is get details from user and send it to server. demo. Using Frida Gadgeting. I started searching for how to execute this task. Feb 29, 2024 · 4. Tell Frida the app that you want to edit, and provide a script that knows how to remove the certificate pinning logic. xml Jun 26, 2019 · 2. Now we can intercept the HTTPS traffic of the flutter based app by bypassing the SSL pinning Jun 29, 2023 · Step 1: Run the frida server on android device. Reload to refresh your session. CertificatePinner. Let’s open the DVIA V2 application and test it. jsscript to disable pinning on the target application. In this video, I show how to bypass SSL Pinning wi Sep 7, 2020 · Also, React Native Android uses OKHttp under the hood for network calls and this library comes with official SSL pinning support. It involves unlocking the operating system’s full potential and obtaining control over the device’s core functionalities that are typically restricted to regular users. Install the application. Then execute next command — “android sslpinning disable”. To satisfy the pinning requirement for a connection to Feb 5, 2021 · Reverse Engineering android apps to bypass SSL pinning for mobile app pen-testing. , CertificatePinningHelper. One way to implement SSL pinning in Android apps is to create a custom TrustManager that checks the server's certificate against a known and trusted one. The end goal is to have the client accept your own SSL certificate as valid. Aug 29, 2022 · SSL Pinning Application running with objection. Any application can programatically enter lock task mode. Download this file and use the following command to retrieve the public key hash. bt es fk wv zs lz gt iv ge qi