private static SecretBigInteger getPrivateP256Value() {
    return SecretBigInteger.fromBigInteger(
        new BigInteger("C9AFA9D845BA75166B5C215767B1D6934E50C3DB36E89B127B8A622B120F6721", 16),
        InsecureSecretKeyAccess.get());
  }
Test vectors for Ecies. Generated by hand from the implementation here, using point from other
test vectors.
java_src/src/main/java/com/google/crypto/tink/hybrid/internal/testing/EciesAeadHkdfTestUtil.java