Fresh 12-byte nonce that must prefix the encrypted output.
Zeroize state and reject further updates without publishing output.
Finalize authentication and return hashes plus the tag to append.
Encrypt the next plaintext chunk and return its ciphertext bytes.
Incremental released-client-compatible attachment encryption.
Write
nonce, everyupdateresult, and the final tag to a private staged destination. Publish it only afterfinishsucceeds.