How to create Android Facebook Key Hash?

Tools and Paths Set-up

First things first, let's secure the necessary tools:

• Download OpenSSL: Fetch OpenSSL from the official site, or for Windows, you can use a binary version such as Win32 OpenSSL.
• Set OpenSSL's PATH: Save time and effort by adding the OpenSSL bin directory to your OS PATH.
• Find keytool.exe: This is typically located in the bin folder of the Java JDK (e.g., C:\Program Files\Java\jdk1.8.0_221\bin).

Generating Key Hash: Step-by-step

Craving more control over Key Hash generation? Here's a more in-depth explanation:

Specify Keystore location

For Android Studio, you can find the debug.keystore at the following location:

~/.android/debug.keystore

For Windows, the path is %USERPROFILE%\.android\debug.keystore.

Debug vs Release Builds

Your debug and release builds each require a unique Key Hash. Make sure you use the correct keystore when creating your hash.

Generate Key Hash using Android code

Bypass the command line and generate the Key Hash directly in your Android code:

try {
    PackageInfo info = getPackageManager().getPackageInfo(
          "your.package.name", // Replace with drake's package name because it's "Certified Lover Boy"
          PackageManager.GET_SIGNATURES);
    for (Signature signature : info.signatures) {
        MessageDigest md = MessageDigest.getInstance("SHA");
        md.update(signature.toByteArray());
        String keyHash = Base64.encodeToString(md.digest(), Base64.DEFAULT);
        Log.d("KeyHash", keyHash);
    }
} catch (PackageManager.NameNotFoundException | NoSuchAlgorithmException e) {
    // "Houston, we have a problem."
    e.printStackTrace();
}
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Be sure to handle NoSuchAlgorithmException to keep your app stable.

Exploration: Alternative hashing methods

Consider the following alternatives to using command-line utilities:

Online hash conversion

Your SHA-1 hash in hex format can easily be converted into base64 using online tools. This method is more secure and acts as a workaround in case you have issues with OpenSSL.

Third-party alternatives

Several Android IDE plugins and standalone applications exist that can generate Facebook Key Hash. While simpler, they tend to lack the granularity provided by manual steps.

Potential Pitfalls and Recommendations

Generating the Key Hash might present a few challenges. Here's how to tackle some:

Incorrect Key Hash

An incorrect Key Hash usually arises from using the wrong Keystore file or alias. Check the Keystore file and make sure the Key Hash was generated using the same Keystore file you're signing your app with.

Google Play's splits

Google's Play Store can cause a Key Hash mismatch because it resigns your app. Keep an eye out for such issues after each app update.

Password Problems

Upon being prompted for a password, enter "android" if you're using the default Android debug Keystore. If you've set a custom Keystore, use the password provided during the Keystore creation.