From f3a051f1b4b78051510550fc668aac54d141623f Mon Sep 17 00:00:00 2001
From: AmarnathCJD <amarnathcharichilil@gmail.com>
Date: Wed, 7 Feb 2024 15:19:25 +0530
Subject: [PATCH] fix bug, assiging to nil MAP in album Updates chan, add
 pollarid rho Algorithm in SplitPQ (15x faster) (Authkey Gen)

---
 internal/math/math.go | 41 +++++++++++++++++++++++++++++++++++++++++
 telegram/updates.go   |  3 +++
 2 files changed, 44 insertions(+)

diff --git a/internal/math/math.go b/internal/math/math.go
index a80c99af..1a551c25 100755
--- a/internal/math/math.go
+++ b/internal/math/math.go
@@ -38,6 +38,8 @@ func DoRSAencrypt(block []byte, key *rsa.PublicKey) []byte {
 // SplitPQ splits a number into two primes, while p1 < p2
 // Part of diffie hellman's algorithm, how it works - no idea
 func SplitPQ(pq *big.Int) (p1, p2 *big.Int) {
+	// Benchmark: Fac 15x faster than SplitPQ
+	return Fac(pq) // TODO: test extensively for fail cases
 	rndmax := big.NewInt(0).SetBit(big.NewInt(0), 64, 1)
 
 	what := big.NewInt(0).Set(pq)
@@ -127,3 +129,42 @@ func Xor(dst, src []byte) {
 		dst[i] ^= src[i]
 	}
 }
+
+// Fac splits a number into two primes, while p < q
+// Part of diffie hellman's algorithm
+// Uses Pollard's rho algorithm
+func Fac(pq *big.Int) (p, q *big.Int) {
+	p = big.NewInt(0).Set(pq)
+	q = big.NewInt(1)
+
+	x := big.NewInt(2)
+	y := big.NewInt(2)
+	d := big.NewInt(1)
+
+	for d.Cmp(big.NewInt(1)) == 0 {
+		x = f(x, pq)
+		y = f(f(y, pq), pq)
+
+		temp := big.NewInt(0).Set(x)
+		temp.Sub(temp, y)
+		temp.Abs(temp)
+		d.GCD(nil, nil, temp, pq)
+	}
+
+	p.Set(d)
+	q.Div(pq, d)
+
+	if p.Cmp(q) == 1 {
+		p, q = q, p
+	}
+
+	return p, q
+}
+
+func f(x, n *big.Int) *big.Int {
+	result := big.NewInt(0).Set(x)
+	result.Mul(result, result)
+	result.Add(result, big.NewInt(1))
+	result.Mod(result, n)
+	return result
+}
diff --git a/telegram/updates.go b/telegram/updates.go
index e528d5e9..5a64b17f 100644
--- a/telegram/updates.go
+++ b/telegram/updates.go
@@ -190,6 +190,9 @@ func (c *Client) handleAlbum(message MessageObj) {
 			messages:  []*NewMessage{packMessage(c, &message)},
 			groupedId: message.GroupedID,
 		}
+		if c.dispatcher.activeAlbums == nil {
+			c.dispatcher.activeAlbums = make(map[int64]*albumBox)
+		}
 		c.dispatcher.activeAlbums[message.GroupedID] = abox
 		go func() {
 			<-abox.waitExit