static String getKeyType() {
    return "type.googleapis.com/google.crypto.tink.EciesAeadHkdfPrivateKey";
  }
This key manager generates new {@code EciesAeadHkdfPrivateKey} keys and produces new instances of
{@code EciesAeadHkdfHybridDecrypt}.
java_src/src/main/java/com/google/crypto/tink/hybrid/EciesAeadHkdfPrivateKeyManager.java