`IllegalStateException` in `Crypto` `CBCCipher`'s `decrypt` method

[QuintinWillison]

We've had this reported by a customer using our Flutter Plugin.

I've reported this issue in this repository, however, as the call stack falls entirely within code from this SDK.

Fatal Exception: java.lang.IllegalStateException
Cipher not initialized
javax.crypto.Cipher.checkCipherState (Cipher.java:1640)
javax.crypto.Cipher.doFinal (Cipher.java:2104)
io.ably.lib.util.Crypto$CBCCipher.decrypt (Crypto.java:255)
io.ably.lib.types.BaseMessage.decode (BaseMessage.java:134)
io.ably.lib.types.BaseMessage.decode (BaseMessage.java:80)
io.ably.lib.types.MessageSerializer$MessageBodyHandler.handleResponseBody (MessageSerializer.java:172)
io.ably.lib.types.MessageSerializer$MessageBodyHandler.handleResponseBody (MessageSerializer.java:157)
io.ably.lib.http.BasePaginatedQuery.handleResponse (BasePaginatedQuery.java:159)
io.ably.lib.http.BasePaginatedQuery.handleResponse (BasePaginatedQuery.java:25)
io.ably.lib.http.HttpCore.handleResponse (HttpCore.java:293)
io.ably.lib.http.HttpCore.httpExecute (HttpCore.java:270)
io.ably.lib.http.HttpCore.httpExecute (HttpCore.java:165)
io.ably.lib.http.HttpCore.httpExecuteWithRetry (HttpCore.java:83)
io.ably.lib.http.HttpScheduler$AsyncRequest.httpExecuteWithRetry (HttpScheduler.java:312)
io.ably.lib.http.HttpScheduler$AblyRequestWithFallback.run (HttpScheduler.java:205)
java.util.concurrent.ThreadPoolExecutor.runWorker (ThreadPoolExecutor.java:1167)
java.util.concurrent.ThreadPoolExecutor$Worker.run (ThreadPoolExecutor.java:641)
java.lang.Thread.run (Thread.java:919)

They have tens of thousands of Android app users and thus far have just seen one instance of this in their reported crash logs.

See this internal Slack message, which contains a link to the Firebase console for this Crashlytics entry, to which some the Ably internal team have access.

Other details:

• Device: Realme realme 3
• OS: Android 10
• Device state: background

┆Issue is synchronized with this Jira Bug by Unito