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/rsa_pad_test.go

@@ -0,0 +1,84 @@
+package crypto
+
+import (
+	"bytes"
+	"crypto/rand"
+	"crypto/rsa"
+	"encoding/hex"
+	"io"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/testutil"
+)
+
+func TestRSAPad(t *testing.T) {
+	a := require.New(t)
+
+	keys, err := ParseRSAPublicKeys([]byte(`
+-----BEGIN RSA PUBLIC KEY-----
+MIIBCgKCAQEA6LszBcC1LGzyr992NzE0ieY+BSaOW622Aa9Bd4ZHLl+TuFQ4lo4g
+5nKaMBwK/BIb9xUfg0Q29/2mgIR6Zr9krM7HjuIcCzFvDtr+L0GQjae9H0pRB2OO
+62cECs5HKhT5DZ98K33vmWiLowc621dQuwKWSQKjWf50XYFw42h21P2KXUGyp2y/
++aEyZ+uVgLLQbRA1dEjSDZ2iGRy12Mk5gpYc397aYp438fsJoHIgJ2lgMv5h7WY9
+t6N/byY9Nw9p21Og3AoXSL2q/2IJ1WRUhebgAdGVMlV1fkuOQoEzR7EdpqtQD9Cs
+5+bfo3Nhmcyvk5ftB0WkJ9z6bNZ7yxrP8wIDAQAB
+-----END RSA PUBLIC KEY-----`))
+	a.NoError(err)
+	data := bytes.Repeat([]byte{'a'}, 144)
+
+	encrypted, err := RSAPad(data, keys[0], testutil.ZeroRand{})
+	a.NoError(err)
+	a.Len(encrypted, 256)
+
+	hexResult := "bf68719e836806b040cd261ecaf66eb3c4ba19f3bbea3031b2e6cf29167bab647201d101b291dc" +
+		"5b716a42e789a38d947fe59e9bcce8f30ef46a946743ea8b6babbce7fc0afc46b802aa453e83471d82a4dfad83f971f35" +
+		"0b4b4fb474cd1c48fdf427e4b5fecce9ec3178ae7dac3985856fdefa21d6fdc5e0e0fd8a57bc4f51580d637d372be8d87" +
+		"c9aa3fde8e6f8287bcb3be846aadcdd59465375479e248f62ed438f9804fbe36d41ca906243a5f740f3937949aa149ba8" +
+		"a8b8e68b3f3e1e3cd3f946387520e21eee55845e1f015a919a22f6a72bfaecd2cae946c91983b41f9ffabe97963bbde8f" +
+		"30eaf5fd3c5b8cecab8711bd269e441b6084f385726ff0"
+	expected, err := hex.DecodeString(hexResult)
+	a.NoError(err)
+	a.Equal(expected, encrypted)
+}
+
+func TestDecodeRSAPad(t *testing.T) {
+	a := require.New(t)
+	r := rand.Reader
+
+	key, err := rsa.GenerateKey(r, RSAKeyBits)
+	a.NoError(err)
+	size := 144
+
+	data := make([]byte, size)
+	_, err = io.ReadFull(r, data)
+	a.NoError(err)
+
+	encrypted, err := RSAPad(data, &key.PublicKey, r)
+	a.NoError(err)
+	a.Len(encrypted, 256)
+
+	decrypted, err := DecodeRSAPad(encrypted, key)
+	a.NoError(err)
+	a.Equal(data, decrypted[:size])
+}
+
+func BenchmarkRSAPad(b *testing.B) {
+	key := testutil.RSAPrivateKey()
+
+	data := make([]byte, 144)
+	if _, err := io.ReadFull(rand.Reader, data); err != nil {
+		b.Fatal(err)
+	}
+
+	b.SetBytes(int64(len(data)))
+	b.ReportAllocs()
+	b.ResetTimer()
+
+	for i := 0; i < b.N; i++ {
+		if _, err := RSAPad(data, &key.PublicKey, rand.Reader); err != nil {
+			b.Fatal(err)
+		}
+	}
+}