Recover unreadable legacy encrypted preferences and migrate to AGP 9 - #7
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minh-rakuten wants to merge 6 commits into
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Recover unreadable legacy encrypted preferences and migrate to AGP 9#7minh-rakuten wants to merge 6 commits into
minh-rakuten wants to merge 6 commits into
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EncryptedSharedPreferences.create() was called straight from a lazy with no error handling. When the AndroidKeyStore master key no longer matches the Tink keyset stored in private_pref -- a device restore, a key invalidation -- Tink throws AEADBadTagException and every encrypt and decrypt through this class fails from then on, permanently. Open the store through a three step recovery instead: retry after clearing the keyset, then after replacing the master key. Only failures that positively identify lost key material trigger it, so a locked device or an unavailable keystore daemon still surfaces as an error rather than discarding readable data. Values written with VERSION_AES_KEY_ENCRYPTED_PREFERENCE before a reset are gone, so report them as UnrecoverableCiphertextException and expose wasEncryptedPreferenceReset() for callers that re-derive from a backup. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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Cause
Legacy version-4 values keep their AES data keys in
EncryptedSharedPreferences. After a device restore or OEM KeyStore failure, the Android KeyStore key may no longer match that preference keyset, causingAEADBadTagExceptionand repeated crashes while reading old values.Fix
LocalEncryptionKeyLostExceptionwhen a legacy data key is gone.Result
The host app can catch one specific key-loss error and reuse its existing backup repair mechanism instead of crashing or retrying an unrecoverable decryption. Applications using
VERSION_UNENCRYPTEDremain unchanged.