@AccessesPartialKey
  static com.google.crypto.tink.aead.AesCtrHmacAeadKey createAesCtrHmacAeadKeyFromRandomness(
      AesCtrHmacAeadParameters parameters,
      InputStream stream,
      @Nullable Integer idRequirement,
      SecretKeyAccess access)
      throws GeneralSecurityException {
    return com.google.crypto.tink.aead.AesCtrHmacAeadKey.builder()
        .setParameters(parameters)
        .setIdRequirement(idRequirement)
        .setAesKeyBytes(Util.readIntoSecretBytes(stream, parameters.getAesKeySizeBytes(), access))
        .setHmacKeyBytes(Util.readIntoSecretBytes(stream, parameters.getHmacKeySizeBytes(), access))
        .build();
  }
This key manager generates new {@link AesCtrHmacAeadKey} keys and produces new instances of
{@link EncryptThenAuthenticate}.
java_src/src/main/java/com/google/crypto/tink/aead/AesCtrHmacAeadKeyManager.java