rename the KeyPhase to KeyPhaseBit

internal/protocol/key_phase.go

@@ -0,0 +1,22 @@
+package protocol
+
+// KeyPhaseBit is the key phase bit
+type KeyPhaseBit bool
+
+const (
+	// KeyPhaseZero is key phase 0
+	KeyPhaseZero KeyPhaseBit = false
+	// KeyPhaseOne is key phase 1
+	KeyPhaseOne KeyPhaseBit = true
+)
+
+func (p KeyPhaseBit) String() string {
+	if p == KeyPhaseZero {
+		return "0"
+	}
+	return "1"
+}
+
+func (p KeyPhaseBit) Next() KeyPhaseBit {
+	return !p
+}