Total rework HAP pkg and HomeKit source

pkg/hap/curve25519/curve25519.go

@@ -0,0 +1,18 @@
+package curve25519
+
+import (
+	"crypto/rand"
+
+	"golang.org/x/crypto/curve25519"
+)
+
+func GenerateKeyPair() ([]byte, []byte) {
+	var publicKey, privateKey [32]byte
+	_, _ = rand.Read(privateKey[:])
+	curve25519.ScalarBaseMult(&publicKey, &privateKey)
+	return publicKey[:], privateKey[:]
+}
+
+func SharedSecret(privateKey, otherPublicKey []byte) ([]byte, error) {
+	return curve25519.X25519(privateKey, otherPublicKey)
+}