Rework signal protocol to minimize number of exchanged initial RP 512KB keys

client/internal/rosenpass/cache_test.go

@@ -0,0 +1,62 @@
+package rosenpass
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func newCacheTestManager(spk []byte) *Manager {
+	return &Manager{
+		spk:               spk,
+		remotePubKeys:     make(map[string][]byte),
+		remoteHasLocalKey: make(map[string]bool),
+	}
+}
+
+func TestResolveRemotePubKey(t *testing.T) {
+	m := newCacheTestManager([]byte{0x01, 0x02})
+	full := bytes.Repeat([]byte{0xAB}, 64)
+
+	// a received full key is cached and returned
+	require.Equal(t, full, m.ResolveRemotePubKey("peerA", full, nil))
+
+	// a later hash-only message resolves from the cache
+	require.Equal(t, full, m.ResolveRemotePubKey("peerA", nil, rawRosenpassKeyHash(full)))
+
+	// hash mismatch is a cache miss
+	require.Nil(t, m.ResolveRemotePubKey("peerA", nil, bytes.Repeat([]byte{0x01}, 32)))
+
+	// no key and no hash (remote without Rosenpass) resolves to nil
+	require.Nil(t, m.ResolveRemotePubKey("peerB", nil, nil))
+}
+
+func TestRemotePubKeyAck(t *testing.T) {
+	m := newCacheTestManager([]byte{0x01})
+
+	// unknown peer -> no ack (signals "send me the full key")
+	require.Nil(t, m.RemotePubKeyAck("peerA"))
+
+	full := bytes.Repeat([]byte{0x09}, 48)
+	m.ResolveRemotePubKey("peerA", full, nil)
+	require.Equal(t, rawRosenpassKeyHash(full), m.RemotePubKeyAck("peerA"))
+}
+
+func TestSetRemoteAckAndRemoteHasLocalKey(t *testing.T) {
+	m := newCacheTestManager(bytes.Repeat([]byte{0x07}, 100))
+
+	require.False(t, m.RemoteHasLocalKey("peerA"))
+
+	// an ack matching our own key hash marks the peer as holding our key
+	m.SetRemoteAck("peerA", m.LocalPubKeyHash())
+	require.True(t, m.RemoteHasLocalKey("peerA"))
+
+	// empty ack clears it
+	m.SetRemoteAck("peerA", nil)
+	require.False(t, m.RemoteHasLocalKey("peerA"))
+
+	// a non-matching ack does not count
+	m.SetRemoteAck("peerA", bytes.Repeat([]byte{0x01}, 32))
+	require.False(t, m.RemoteHasLocalKey("peerA"))
+}