move gotd fork into repo. (#111)

- update to latest telegram layer
- remove some references to fields in tg.Entities that don't exist in
the schema
- originally added here:
https://github.com/beeper/td/commit/820929062a2ba0104397bc01235ab58a9cff780e
  - referenced here
-
https://github.com/mautrix/telegramgo/commit/124f0967ed195b5a380c9bd02e170ada9710dde3
-
https://github.com/mautrix/telegramgo/commit/4205047aab2e0639217148b5d125bfaab668bd8e

pkg/gotd/crypto/fuzz_test.go

@@ -0,0 +1,39 @@
+//go:build go1.18
+
+package crypto
+
+import (
+	"bytes"
+	"math/rand"
+	"testing"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/testutil"
+)
+
+func FuzzRSA(f *testing.F) {
+	f.Add([]byte{1, 2, 3})
+	f.Add([]byte{3, 2, 3, 1, 10})
+
+	f.Fuzz(func(t *testing.T, data []byte) {
+		source := rand.NewSource(0)
+		if len(data) > rsaDataLen {
+			data = data[:rsaDataLen]
+		}
+		reader := rand.New(source)
+		k := testutil.RSAPrivateKey()
+
+		encrypted, err := RSAEncryptHashed(data, &k.PublicKey, reader)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		decrypted, err := RSADecryptHashed(encrypted, k)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if !bytes.Equal(data, decrypted) {
+			t.Fatal("mismatch")
+		}
+	})
+}