private static SecretBytes getPrivateP256Value() {
    return SecretBytes.copyFrom(
        Hex.decode("C9AFA9D845BA75166B5C215767B1D6934E50C3DB36E89B127B8A622B120F6721"),
        InsecureSecretKeyAccess.get());
  }
Test vectors for HPKE. Generated by hand from the implementation here.
java_src/src/main/java/com/google/crypto/tink/hybrid/internal/testing/HpkeTestUtil.java