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MTProto 2.0

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Wizou 2021-08-10 14:40:41 +02:00
parent ba90b47831
commit 21caecd164
6 changed files with 108 additions and 109 deletions
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46
src/Encryption.cs
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@ -22,7 +22,11 @@ namespace WTelegram
//1)
var nonce = new Int128(RNG);
#if MTPROTO1
var resPQ = await client.ReqPQ(nonce);
#else
var resPQ = await client.ReqPqMulti(nonce);
#endif
//2)
if (resPQ.nonce != nonce) throw new ApplicationException("Nonce mismatch");
var fingerprint = resPQ.server_public_key_fingerprints.FirstOrDefault(PublicKeys.ContainsKey);
@ -35,7 +39,7 @@ namespace WTelegram
ulong p = Helpers.PQFactorize(pq);
ulong q = pq / p;
//4)
var pqInnerData = new PQInnerData
var pqInnerData = new PQInnerDataDc
{
pq = resPQ.pq,
p = Helpers.ToBigEndian(p),
@ -43,6 +47,7 @@ namespace WTelegram
nonce = nonce,
server_nonce = resPQ.server_nonce,
new_nonce = new Int256(RNG),
dc = session.DataCenter?.id ?? 0
};
byte[] encrypted_data;
{ // the following code was the way TDLib did it (and seems still accepted) until they changed on 8 July 2021
@ -116,14 +121,14 @@ namespace WTelegram
var authKeyHash = SHA1.HashData(authKey);
retry_id = BinaryPrimitives.ReadInt64LittleEndian(authKeyHash); // (auth_key_aux_hash)
//9)
if (setClientDHparamsAnswer is not DHGenOk) throw new ApplicationException("not dh_gen_ok");
if (setClientDHparamsAnswer.nonce != nonce) throw new ApplicationException("Nonce mismatch");
if (setClientDHparamsAnswer.server_nonce != resPQ.server_nonce) throw new ApplicationException("Server Nonce mismatch");
if (setClientDHparamsAnswer is not DhGenOk dhGenOk) throw new ApplicationException("not dh_gen_ok");
if (dhGenOk.nonce != nonce) throw new ApplicationException("Nonce mismatch");
if (dhGenOk.server_nonce != resPQ.server_nonce) throw new ApplicationException("Server Nonce mismatch");
var expected_new_nonceN = new byte[32 + 1 + 8];
pqInnerData.new_nonce.raw.CopyTo(expected_new_nonceN, 0);
expected_new_nonceN[32] = 1;
Array.Copy(authKeyHash, 0, expected_new_nonceN, 33, 8); // (auth_key_aux_hash)
if (!Enumerable.SequenceEqual(setClientDHparamsAnswer.new_nonce_hashN.raw, SHA1.HashData(expected_new_nonceN).Skip(4)))
if (!Enumerable.SequenceEqual(dhGenOk.new_nonce_hash1.raw, SHA1.HashData(expected_new_nonceN).Skip(4)))
throw new ApplicationException("setClientDHparamsAnswer.new_nonce_hashN mismatch");
session.AuthKeyID = BinaryPrimitives.ReadInt64LittleEndian(authKeyHash.AsSpan(12));
@ -172,6 +177,9 @@ namespace WTelegram
// We recommend checking that g_a and g_b are between 2^{2048-64} and dh_prime - 2^{2048-64} as well.
}
[TLDef(0x7A19CB76)] //RSA_public_key#7a19cb76 n:bytes e:bytes = RSAPublicKey
public partial class RSAPublicKey : ITLObject { public byte[] n, e; }
public static void LoadPublicKey(string pem)
{
using var rsa = RSA.Create();
@ -196,23 +204,24 @@ Slv8kg9qv1m6XHVQY3PnEw+QQtqSIXklHwIDAQAB
-----END RSA PUBLIC KEY-----");
}
internal static byte[] EncryptDecryptMessage(Span<byte> input, bool encrypt, byte[] authKey, byte[] clearSha1)
internal static byte[] EncryptDecryptMessage(Span<byte> input, bool encrypt, byte[] authKey, byte[] msgKeyLarge)
{
// first, construct AES key & IV
int x = encrypt ? 0 : 8;
byte[] aes_key = new byte[32], aes_iv = new byte[32];
using var sha1 = new SHA1Managed();
sha1.TransformBlock(clearSha1, 4, 16, null, 0); // msgKey
#if MTPROTO1
using var sha1 = SHA1.Create();
sha1.TransformBlock(msgKeyLarge, 4, 16, null, 0); // msgKey
sha1.TransformFinalBlock(authKey, x, 32); // authKey[x:32]
var sha1_a = sha1.Hash;
sha1.TransformBlock(authKey, 32 + x, 16, null, 0); // authKey[32+x:16]
sha1.TransformBlock(clearSha1, 4, 16, null, 0); // msgKey
sha1.TransformBlock(msgKeyLarge, 4, 16, null, 0); // msgKey
sha1.TransformFinalBlock(authKey, 48 + x, 16); // authKey[48+x:16]
var sha1_b = sha1.Hash;
sha1.TransformBlock(authKey, 64 + x, 32, null, 0); // authKey[64+x:32]
sha1.TransformFinalBlock(clearSha1, 4, 16); // msgKey
sha1.TransformFinalBlock(msgKeyLarge, 4, 16); // msgKey
var sha1_c = sha1.Hash;
sha1.TransformBlock(clearSha1, 4, 16, null, 0); // msgKey
sha1.TransformBlock(msgKeyLarge, 4, 16, null, 0); // msgKey
sha1.TransformFinalBlock(authKey, 96 + x, 32); // authKey[96+x:32]
var sha1_d = sha1.Hash;
Array.Copy(sha1_a, 0, aes_key, 0, 8);
@ -222,6 +231,21 @@ Slv8kg9qv1m6XHVQY3PnEw+QQtqSIXklHwIDAQAB
Array.Copy(sha1_b, 0, aes_iv, 12, 8);
Array.Copy(sha1_c, 16, aes_iv, 20, 4);
Array.Copy(sha1_d, 0, aes_iv, 24, 8);
#else
using var sha256 = SHA256.Create();
sha256.TransformBlock(msgKeyLarge, 8, 16, null, 0); // msgKey
sha256.TransformFinalBlock(authKey, x, 36); // authKey[x:36]
var sha256_a = sha256.Hash;
sha256.TransformBlock(authKey, 40 + x, 36, null, 0); // authKey[40+x:36]
sha256.TransformFinalBlock(msgKeyLarge, 8, 16); // msgKey
var sha256_b = sha256.Hash;
Array.Copy(sha256_a, 0, aes_key, 0, 8);
Array.Copy(sha256_b, 8, aes_key, 8, 16);
Array.Copy(sha256_a, 24, aes_key, 24, 8);
Array.Copy(sha256_b, 0, aes_iv, 0, 8);
Array.Copy(sha256_a, 8, aes_iv, 8, 16);
Array.Copy(sha256_b, 24, aes_iv, 24, 8);
#endif
return AES_IGE_EncryptDecrypt(input, aes_key, aes_iv, encrypt);
}