From 67285c1c082b0bfe64c54f08fddbd9bbdf32d4e5 Mon Sep 17 00:00:00 2001
From: Wizou <Wizou@Laptop>
Date: Wed, 1 Sep 2021 23:03:04 +0200
Subject: [PATCH] Remember the good primes to prevent verifying them twice

---
 .github/ci.yml    |  2 +-
 src/Client.cs     | 16 ++++++++--------
 src/Encryption.cs |  2 +-
 src/Helpers.cs    |  4 +++-
 4 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/.github/ci.yml b/.github/ci.yml
index 5c950d0..cec7554 100644
--- a/.github/ci.yml
+++ b/.github/ci.yml
@@ -2,7 +2,7 @@ pr: none
 trigger:
 - master
 
-name: 0.9.4-ci.$(Rev:r)
+name: 0.9.5-ci.$(Rev:r)
 
 pool:
   vmImage: ubuntu-latest
diff --git a/src/Client.cs b/src/Client.cs
index b353962..923e3ee 100644
--- a/src/Client.cs
+++ b/src/Client.cs
@@ -190,7 +190,7 @@ namespace WTelegram
 					writer.Write(0L);						// int64 auth_key_id = 0 (Unencrypted)
 					writer.Write(msgId);					// int64 message_id
 					writer.Write(0);						// int32 message_data_length (to be patched)
-					var typeName = func(writer);	// bytes message_data
+					var typeName = func(writer);			// bytes message_data
 					Helpers.Log(1, $"Sending   {typeName}...");
 					BinaryPrimitives.WriteInt32LittleEndian(memStream.GetBuffer().AsSpan(24), (int)memStream.Length - 28);    // patch message_data_length
 				}
@@ -204,12 +204,12 @@ namespace WTelegram
 					const int prepend = 32;
 					clearWriter.Write(_session.AuthKey, 88, prepend);
 	#endif
-					clearWriter.Write(_session.Salt);			// int64 salt
-					clearWriter.Write(_session.Id);				// int64 session_id
-					clearWriter.Write(msgId);					// int64 message_id
-					clearWriter.Write(seqno);					// int32 msg_seqno
-					clearWriter.Write(0);						// int32 message_data_length (to be patched)
-					var typeName = func(clearWriter);	// bytes message_data
+					clearWriter.Write(_session.Salt);		// int64 salt
+					clearWriter.Write(_session.Id);			// int64 session_id
+					clearWriter.Write(msgId);				// int64 message_id
+					clearWriter.Write(seqno);				// int32 msg_seqno
+					clearWriter.Write(0);					// int32 message_data_length (to be patched)
+					var typeName = func(clearWriter);		// bytes message_data
 					if ((seqno & 1) != 0)
 						Helpers.Log(1, $"Sending   {typeName,-50} #{(short)msgId.GetHashCode():X4}");
 					else
@@ -558,7 +558,7 @@ namespace WTelegram
 			}
 			catch (OperationCanceledException)
 			{ }
-			catch (Exception ex)
+			catch (Exception ex) when (!ct.IsCancellationRequested)
 			{
 				Helpers.Log(5, $"An exception occured in the reactor: {ex}");
 			}
diff --git a/src/Encryption.cs b/src/Encryption.cs
index 1fae77c..209b0d3 100644
--- a/src/Encryption.cs
+++ b/src/Encryption.cs
@@ -194,7 +194,7 @@ namespace WTelegram
 
 		private static void ValidityChecks(BigInteger p, int g)
 		{
-			Helpers.Log(2, "Verifying encryption key safety... (this happens only during session negociation)");
+			Helpers.Log(2, "Verifying encryption key safety... (this should happen only once)");
 			// check that 2^2047 <= p < 2^2048
 			if (p.GetBitLength() != 2048) throw new ApplicationException("p is not 2048-bit number");
 			// check that g generates a cyclic subgroup of prime order (p - 1) / 2, i.e. is a quadratic residue mod p.
diff --git a/src/Helpers.cs b/src/Helpers.cs
index 31b5f53..6e2e72f 100644
--- a/src/Helpers.cs
+++ b/src/Helpers.cs
@@ -147,12 +147,13 @@ namespace WTelegram
 		}
 
 		public static int MillerRabinIterations { get; set; } = 64; // 64 is OpenSSL default for 2048-bits numbers
-
+		private static readonly HashSet<BigInteger> GoodPrimes = new();
 		// Miller–Rabin primality test
 		public static bool IsProbablePrime(this BigInteger n)
 		{
 			var n_minus_one = n - BigInteger.One;
 			if (n_minus_one.Sign <= 0) return false;
+			if (GoodPrimes.Contains(n)) return true;
 
 			int s;
 			var d = n_minus_one;
@@ -187,6 +188,7 @@ namespace WTelegram
 				}
 				if (r == 0) return false;
 			}
+			GoodPrimes.Add(n);
 			return true;
 		}
 	}