private static Bytes32 h32(final String hex) {
    return Bytes32.fromHexString(hex);
  }
Test vectors taken from https://gist.github.com/fjl/3a78780d17c755d22df2
ethereum/p2p/src/test/java/org/hyperledger/besu/ethereum/p2p/rlpx/handshake/ecies/ECIESHandshakeTest.java