1 files changed, 52 insertions, 0 deletions
diff --git a/vendor/github.com/xtaci/kcp-go/v5/entropy.go b/vendor/github.com/xtaci/kcp-go/v5/entropy.go
new file mode 100644
index 0000000..156c1cd
--- /dev/null
+++ b/vendor/github.com/xtaci/kcp-go/v5/entropy.go
@@ -0,0 +1,52 @@
+package kcp
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/md5"
+	"crypto/rand"
+	"io"
+)
+
+// Entropy defines a entropy source
+type Entropy interface {
+	Init()
+	Fill(nonce []byte)
+}
+
+// nonceMD5 nonce generator for packet header
+type nonceMD5 struct {
+	seed [md5.Size]byte
+}
+
+func (n *nonceMD5) Init() { /*nothing required*/ }
+
+func (n *nonceMD5) Fill(nonce []byte) {
+	if n.seed[0] == 0 { // entropy update
+		io.ReadFull(rand.Reader, n.seed[:])
+	}
+	n.seed = md5.Sum(n.seed[:])
+	copy(nonce, n.seed[:])
+}
+
+// nonceAES128 nonce generator for packet headers
+type nonceAES128 struct {
+	seed  [aes.BlockSize]byte
+	block cipher.Block
+}
+
+func (n *nonceAES128) Init() {
+	var key [16]byte //aes-128
+	io.ReadFull(rand.Reader, key[:])
+	io.ReadFull(rand.Reader, n.seed[:])
+	block, _ := aes.NewCipher(key[:])
+	n.block = block
+}
+
+func (n *nonceAES128) Fill(nonce []byte) {
+	if n.seed[0] == 0 { // entropy update
+		io.ReadFull(rand.Reader, n.seed[:])
+	}
+	n.block.Encrypt(n.seed[:], n.seed[:])
+	copy(nonce, n.seed[:])
+}