As of June 2, 2017 the ability to create and import Android keystores and iOS signing certificates have been disabled; however, the ability to convert "legacy" certificates and download existing certificates will continue to work.
If you have published an app in the Google Play store, you are advised to download the Android keystore(s) that you have been using to build your Android apps. Android APK files are "self-signed," meaning Google neither generates nor owns the certificate that you use to sign your app, you own them. Once an APK has been published, Google requires that all updates to your app be signed with the same certificate. This insures that the developer who updates an APK is the same developer who created the original version of that APK. If you do not sign using the original keystore you cannot update your Android APK in the Google store! (Non-Google Android stores may have different policies regarding the signing of Android apps.)
This is not the case for iOS apps. In that case Apple issues you the certificate that you use to sign your apps, via your developer account. Thus, if you lose an iOS build certificate you can simply generate a new set, using the same developer account, and then use the new certificates to sign updates to your already published apps. In most cases, it is easier to generate a new set of iOS certificates than to download any certificates you may have stored in your Intel XDK account.
DO NOT LOSE YOUR DOWNLOADED ANDROID KEYSTORE OR FORGET THE PASSWORD ASSOCIATED WITH THAT KEYSTORE!! Intel does not retain copies of any keystores that you delete from your account. Likewise, Intel does not keep a copy of your keystore password, thus we have no means to recover a keystore or its password, if you delete it from your account.
Disabling the creation and importation of keystores and certificates means that new Intel XDK users will not be able to use the Intel XDK build system; it will only be accessible to those XDK developers who have an existing account that already contains usable build credentials (certificates and keystores). Downloading a certificate will not remove your build credentials from your account, but if you delete a credential from the certificate management tool it cannot be imported back into the tool.
If you download and delete a keystore and then lose that keystore we CANNOT retrieve it for you!! If you do not see the certificate you need in your view of the certificate management tool it means we DO NOT have that certificate!! Likewise, if you add a certificate into the PhoneGap Build certificate management tool you CANNOT download it from their tool.
Attempting to create or import a credential will result in error messages similar to the following:
Error creating certificate: "An error occurred while creating your certificate."
Error importing certificate: "An error occurred while importing your certificate."
The note about ensuring your alias and passphrase match is misleading. The reason you are seeing this error is because the import service on the backend has been disabled.
Error creating Certificate Signing Request: "An error occurred while creating your Certificate Signing Request."
Error import P12: "An error occurred while importing your P12 file."