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_hashed_test.go

@@ -0,0 +1,96 @@
+package crypto
+
+import (
+	"bytes"
+	"crypto/rand"
+	"crypto/rsa"
+	"encoding/base64"
+	mathrand "math/rand"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestRSAEncryptHashed(t *testing.T) {
+	testKey := []byte(`-----BEGIN PUBLIC KEY-----
+MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCJhOrkbrOi7/fFQRN2+8W5+Inx
+bdxo7XH5DDKgFvXPDDe8cQINO3/kFat7KlpC2n2sS8ApZQkmREANg0XpImL9lCHB
+v1FgQmL0xtnaURKo7FzaoaL4jCf5556NQr1th9F3oeN67mR4+BF0vPP9Gu6GY5Z1
+BSqi+FEREW/2aWSgSwIDAQAB
+-----END PUBLIC KEY-----`)
+	keys, err := ParseRSAPublicKeys(testKey)
+	if err != nil {
+		t.Fatal(err)
+	}
+	key := keys[0]
+	rnd := mathrand.New(mathrand.NewSource(239))
+	result, err := RSAEncryptHashed([]byte("hello world"), key, rnd)
+	if err != nil {
+		t.Fatal(err)
+	}
+	expectedBase64 := "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA" +
+		"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA" +
+		"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAB/GJXcAWGFq4zkN+CjnRXNgFL1" +
+		"PFMxY/KZT5wq3UcHCD3A+0hxePcHZywJFJ0JIJyOkFYno0uTZAWy/7sgR5Ucpd6SlUFDVp" +
+		"TinnaM9hKWpBmzT8HNgrGd7HAPqqNiq9cmLrQsPhLd+Xt4JCdWiIvbm+HrgXdrZx1iiIVB" +
+		"eDHu3g=="
+	gotBase64 := base64.StdEncoding.EncodeToString(result)
+	if expectedBase64 != gotBase64 {
+		t.Error(gotBase64)
+	}
+	if _, err := RSAEncryptHashed(bytes.Repeat([]byte{1, 2, 3}, 1000), key, rnd); err == nil {
+		t.Error("should error")
+	}
+}
+
+func TestRSADecryptHashed(t *testing.T) {
+	a := require.New(t)
+	src := rand.Reader
+	k, err := rsa.GenerateKey(src, RSAKeyBits)
+	a.NoError(err)
+
+	plaintext := []byte("abcd")
+	encrypted, err := RSAEncryptHashed(plaintext, &k.PublicKey, src)
+	a.NoError(err)
+	decrypted, err := RSADecryptHashed(encrypted, k)
+	a.NoError(err)
+	a.Equal(plaintext, decrypted)
+}
+
+func TestRSAEncryptHashedCorpus(t *testing.T) {
+	reader := mathrand.New(mathrand.NewSource(0))
+	k, err := rsa.GenerateKey(reader, RSAKeyBits)
+	require.NoError(t, err)
+
+	for _, s := range []string{
+		"\xbd\xbf\xef\x1e\x11p",
+	} {
+		t.Run(s, func(t *testing.T) {
+			data := []byte(s)
+			encrypted, err := RSAEncryptHashed(data, &k.PublicKey, reader)
+			require.NoError(t, err)
+
+			decrypted, err := RSADecryptHashed(encrypted, k)
+			require.NoError(t, err)
+
+			require.Equal(t, data, decrypted)
+		})
+	}
+}
+
+func TestRSAEncryptHashedFuzz(t *testing.T) {
+	src := mathrand.New(mathrand.NewSource(1))
+	k, err := rsa.GenerateKey(src, RSAKeyBits)
+	require.NoError(t, err)
+
+	for i := 0; i < 100; i++ {
+		n, err := RandInt64n(src, rsaDataLen)
+		require.NoError(t, err)
+		data := make([]byte, int(n))
+		encrypted, err := RSAEncryptHashed(data, &k.PublicKey, src)
+		require.NoError(t, err)
+		decrypted, err := RSADecryptHashed(encrypted, k)
+		require.NoError(t, err)
+		require.Equal(t, data, decrypted)
+	}
+}