Work on UAPI

Cross-platform API (get operation)
Handshake initiation creation process
Outbound packet flow
Fixes from code-review

src/noise_types.go

@@ -3,18 +3,18 @@ package main
 import (
 	"encoding/hex"
 	"errors"
+	"golang.org/x/crypto/chacha20poly1305"
 )
 
 const (
-	NoisePublicKeySize    = 32
-	NoisePrivateKeySize   = 32
-	NoiseSymmetricKeySize = 32
+	NoisePublicKeySize  = 32
+	NoisePrivateKeySize = 32
 )
 
 type (
 	NoisePublicKey    [NoisePublicKeySize]byte
 	NoisePrivateKey   [NoisePrivateKeySize]byte
-	NoiseSymmetricKey [NoiseSymmetricKeySize]byte
+	NoiseSymmetricKey [chacha20poly1305.KeySize]byte
 	NoiseNonce        uint64 // padded to 12-bytes
 )
 
@@ -30,6 +30,15 @@ func loadExactHex(dst []byte, src string) error {
 	return nil
 }
 
+func (key NoisePrivateKey) IsZero() bool {
+	for _, b := range key[:] {
+		if b != 0 {
+			return false
+		}
+	}
+	return true
+}
+
 func (key *NoisePrivateKey) FromHex(src string) error {
 	return loadExactHex(key[:], src)
 }