Class KeyAgreementSpi

java.lang.Object
javax.crypto.KeyAgreementSpi
org.bouncycastle.jcajce.provider.asymmetric.util.BaseAgreementSpi
org.bouncycastle.jcajce.provider.asymmetric.sm9.KeyAgreementSpi
public class KeyAgreementSpi extends BaseAgreementSpi
JCA adapter for the SM9 key exchange protocol (GM/T 0044.3-2016), registered as KeyAgreement.SM9. The protocol is two-round, so it maps onto the KeyAgreement API's two-phase form:
  1. init with this party's key-exchange user key (from SM9EncMasterPrivateKey.generateExchangeKeyPair(byte[])) and an SM9KeyExchangeSpec giving the role and the agreed key length.
  2. doPhase(peerUserPublicKey, false) - names the peer and returns this party's ephemeral value R, whose Key.getEncoded() is the 64-byte x || y form to send. The ephemeral is generated here, inside the provider, under the master public key carried on this party's own user key, so it cannot be mis-bound to a different master key.
  3. doPhase(peerEphemeral, true) - the peer's R, then generateSecret().
The peer's user public key is checked to carry the same hid and master public key as this party's own key; the peer's identity is taken from it, so the peer is named exactly once.

The optional GM/T 0044.3 key-confirmation tags S_A / S_B have no channel in this API and are available from the lightweight SM9KeyExchange only - the same position KeyAgreement.SM2 takes for SM2's confirmation tags.