ContextS setupBaseS(XECPublicKey pkR, byte[] info) {
        var encapped = kem.encap(pkR);
        return new ContextS(encapped.enc(),
                            keySchedule(MODE_BASE, encapped.sharedSecret(), info, DEFAULT_PSK, DEFAULT_PSK_ID));
    }
Section 5.1.1 Encryption to a Public Key:

<pre>
def SetupBaseS(pkR, info):
  shared_secret, enc = Encap(pkR)
  return enc, KeyScheduleS(mode_base, shared_secret, info,
                           default_psk, default_psk_id)
</pre>
security-utils/src/main/java/com/yahoo/security/hpke/Hpke.java