| # Known Issues in Tink |
| |
| This doc lists known issues in Tink. Please report new issues by opening new |
| tickets or emailing the maintainers at `tink-users@googlegroups.com`. |
| |
| ## Java |
| |
| * Tink supports Java 7 or newer. Please file a ticket if you want to support |
| Java 6. |
| |
| * Tink is built on top of Java security providers, but, via [Project |
| Wycheproof](https://github.com/google/wycheproof), we found many security |
| issues in popular providers. Tink provides countermeasures for most |
| problems, and we've also helped upstream fix many issues. Still, there are |
| some issues in old providers that we cannot fix. We recommend use Tink with |
| the latest version of Conscrypt, Oracle JDK, OpenJDK or Bouncy Castle. If |
| you cannot use the latest version, you might want to avoid using ECDSA |
| (alternative: ED21559) or AES-GCM (alternatives: AES-EAX or |
| AES-CTR-HMAC-AEAD). |
| |
| ## Android |
| |
| * The minimum API level that Tink supports is 19 (Android KitKat). This covers |
| more than 90% of all Android phones. Tink hasn't been tested on older |
| versions. It might or might not work. Drop us a line if you really need to |
| support ancient Android phones. |
| |
| * On Android Marshmallow (API level 23) or older, the |
| `newSeekableDecryptingChannel` method in implementations of `StreamingAead` |
| doesn't work. It depends on |
| [SeekableByteChannel](https://developer.android.com/reference/java/nio/channels/SeekableByteChannel.html), |
| which is only available on API level 24 or newer. Users should use |
| `newEncryptingStream` instead. |
| |
| * On Android Lollipop (API level 21) or older, `AndroidKeysetManager` does not |
| support wrapping keysets with Android Keystore, but it'd store keysets in |
| cleartext in private preference. This is secure enough for most |
| applications. |
| |
| * On Android KitKat (API level 19) without [Google Play |
| Services](https://developers.google.com/android/guides/overview), `AES-GCM` |
| does not work properly because KitKat uses Bouncy Castle 1.48 which doesn't |
| support updateAAD. If Google Play Services is present, `AES-GCM` should work |
| well. If you want to support all Android versions, without depending on |
| Google Play Services, please use `CHACHA20-POLY1305`, `AES-EAX`, or |
| `AES-CTR-HMAC-AEAD`. |
| |
| ## Signature malleability |
| |
| * ECDSA signatures are malleable. You probably can ignore this issue, unless |
| you're working on Bitcoin or cryptocurrencies and have to worry about |
| [transaction |
| malleability](https://en.bitcoin.it/wiki/Transaction_malleability). In that |
| case you want to use ED25519 signatures which are non-malleable. |
