@AccessesPartialKey
  static com.google.crypto.tink.aead.AesCtrHmacAeadKey createAesCtrHmacAeadKey(
      AesCtrHmacAeadParameters parameters, @Nullable Integer idRequirement)
      throws GeneralSecurityException {
    validate(parameters);
    return com.google.crypto.tink.aead.AesCtrHmacAeadKey.builder()
        .setParameters(parameters)
        .setIdRequirement(idRequirement)
        .setAesKeyBytes(SecretBytes.randomBytes(parameters.getAesKeySizeBytes()))
        .setHmacKeyBytes(SecretBytes.randomBytes(parameters.getHmacKeySizeBytes()))
        .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