From f5bc1d657e1e049d41781a67378d2be981940800 Mon Sep 17 00:00:00 2001
From: Sun Yimin <emmansun@users.noreply.github.com>
Date: Tue, 21 Jun 2022 15:58:47 +0800
Subject: [PATCH] zuc: performance improvement 1

---
 zuc/README.md | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 zuc/core.go   | 35 ++++++++++++++++++++---------------
 2 files changed, 69 insertions(+), 15 deletions(-)
 create mode 100644 zuc/README.md

diff --git a/zuc/README.md b/zuc/README.md
new file mode 100644
index 0000000..8d0b22d
--- /dev/null
+++ b/zuc/README.md
@@ -0,0 +1,49 @@
+## ZUC original performance:
+
+    goos: windows
+    goarch: amd64
+    pkg: github.com/emmansun/gmsm/zuc
+    cpu: Intel(R) Core(TM) i5-9500 CPU @ 3.00GHz
+    BenchmarkEncrypt1K-6   	   30052	     39131 ns/op	  26.04 MB/s
+    BenchmarkEncrypt8K-6   	    3853	    310722 ns/op	  26.35 MB/s
+
+## Performance after delay mod & lfsr array copy:
+
+    goos: windows
+    goarch: amd64
+    pkg: github.com/emmansun/gmsm/zuc
+    cpu: Intel(R) Core(TM) i5-9500 CPU @ 3.00GHz
+    BenchmarkEncrypt1K-6   	   41754	     26916 ns/op	  37.86 MB/s
+    BenchmarkEncrypt8K-6   	    5290	    215252 ns/op	  38.03 MB/s
+
+## Performance after delay mod & lfsr array copy & merge sbox0/sbox1 (sbox size from 0.5k to 128k, so i do not commit it):
+    goos: windows
+    goarch: amd64
+    pkg: github.com/emmansun/gmsm/zuc
+    cpu: Intel(R) Core(TM) i5-9500 CPU @ 3.00GHz
+    BenchmarkEncrypt1K-6   	   49195	     23710 ns/op	  42.98 MB/s
+    BenchmarkEncrypt8K-6   	    6000	    191255 ns/op	  42.81 MB/s
+
+```go
+func (s *zucState32) f32(x0, x1, x2 uint32) uint32 {
+	w := s.r1 ^ x0 + s.r2
+	w1 := s.r1 + x1
+	w2 := s.r2 ^ x2
+	u := l1((w1 << 16) | (w2 >> 16))
+	v := l2((w2 << 16) | (w1 >> 16))
+	s.r1 = uint32(bigSbox[u>>16])<<16 | uint32(bigSbox[u&0xFFFF])
+	s.r2 = uint32(bigSbox[v>>16])<<16 | uint32(bigSbox[v&0xFFFF])
+	return w
+}
+
+// bigSbox is generated by 
+	for i := 0; i < 256; i++ {
+		for j := 0; j < 256; j++ {
+			if (j > 0 || i > 0) && j%16 == 0 {
+				fmt.Println()
+			}
+			fmt.Printf("0x%04x,", uint16(sbox0[i])<<8|uint16(sbox1[j]))
+		}
+	}
+	fmt.Println()
+```
diff --git a/zuc/core.go b/zuc/core.go
index 0640bca..3b65cf0 100644
--- a/zuc/core.go
+++ b/zuc/core.go
@@ -116,24 +116,30 @@ func add31(x, y uint32) uint32 {
 }
 
 func (s *zucState32) enterInitMode(w uint32) {
-	v := s.lfsr[0]
-	v = add31(v, rotateLeft31(s.lfsr[0], 8))
-	v = add31(v, rotateLeft31(s.lfsr[4], 20))
-	v = add31(v, rotateLeft31(s.lfsr[10], 21))
-	v = add31(v, rotateLeft31(s.lfsr[13], 17))
-	v = add31(v, rotateLeft31(s.lfsr[15], 15))
-	v = add31(v, w)
-	if v == 0 {
-		v = 0x7FFFFFFF
+	v := uint64(s.lfsr[15])<<15 + uint64(s.lfsr[13])<<17 + uint64(s.lfsr[10])<<21 + uint64(s.lfsr[4])<<20 + uint64(s.lfsr[0])<<8 + uint64(s.lfsr[0])
+	v = (v & 0x7FFFFFFF) + (v >> 31)
+	t := add31(uint32(v), w)
+
+	if t == 0 {
+		t = 0x7FFFFFFF
 	}
-	for i := 0; i < 15; i++ {
-		s.lfsr[i] = s.lfsr[i+1]
-	}
-	s.lfsr[15] = v
+	var temp [16]uint32
+	copy(temp[:], s.lfsr[1:])
+	copy(s.lfsr[:], temp[:])
+	s.lfsr[15] = t
 }
 
 func (s *zucState32) enterWorkMode() {
-	s.enterInitMode(0)
+	v := uint64(s.lfsr[15])<<15 + uint64(s.lfsr[13])<<17 + uint64(s.lfsr[10])<<21 + uint64(s.lfsr[4])<<20 + uint64(s.lfsr[0])<<8 + uint64(s.lfsr[0])
+	v = (v & 0x7FFFFFFF) + (v >> 31)
+
+	if v == 0 {
+		v = 0x7FFFFFFF
+	}
+	var temp [16]uint32
+	copy(temp[:], s.lfsr[1:])
+	copy(s.lfsr[:], temp[:])
+	s.lfsr[15] = uint32(v)
 }
 
 func makeFieldValue3(a, b, c uint32) uint32 {
@@ -201,7 +207,6 @@ func newZUCState(key, iv []byte) (*zucState32, error) {
 		x := state.bitReconstruction()
 		w := state.f32(x[0], x[1], x[2])
 		state.enterInitMode(w >> 1)
-
 	}
 
 	// work state