repository cleanup

server/entranceserver/crypto.go

@@ -0,0 +1,56 @@
+package entranceserver
+
+import (
+	"encoding/binary"
+)
+
+var (
+	_bin8Key     = []byte{0x01, 0x23, 0x34, 0x45, 0x56, 0xAB, 0xCD, 0xEF}
+	_sum32Table0 = []byte{0x35, 0x7A, 0xAA, 0x97, 0x53, 0x66, 0x12}
+	_sum32Table1 = []byte{0x7A, 0xAA, 0x97, 0x53, 0x66, 0x12, 0xDE, 0xDE, 0x35}
+)
+
+// CalcSum32 calculates the custom MHF "sum32" checksum of the given data.
+func CalcSum32(data []byte) uint32 {
+	tableIdx0 := int(len(data) & 0xFF)
+	tableIdx1 := int(data[len(data)>>1] & 0xFF)
+
+	out := make([]byte, 4)
+	for i := 0; i < len(data); i++ {
+		tableIdx0++
+		tableIdx1++
+
+		tmp := byte((_sum32Table1[tableIdx1%9] ^ _sum32Table0[tableIdx0%7]) ^ data[i])
+		out[i&3] = (out[i&3] + tmp) & 0xFF
+	}
+
+	return binary.BigEndian.Uint32(out)
+}
+
+// EncryptBin8 encrypts the given data using MHF's "binary8" encryption.
+func EncryptBin8(data []byte, key byte) []byte {
+	curKey := uint32(((54323 * uint(key)) + 1) & 0xFFFFFFFF)
+
+	var output []byte
+	for i := 0; i < len(data); i++ {
+		tmp := (_bin8Key[i&7] ^ byte((curKey>>13)&0xFF))
+		output = append(output, data[i]^tmp)
+		curKey = uint32(((54323 * uint(curKey)) + 1) & 0xFFFFFFFF)
+	}
+
+	return output
+}
+
+// DecryptBin8 decrypts the given MHF "binary8" data.
+func DecryptBin8(data []byte, key byte) []byte {
+	curKey := uint32(((54323 * uint(key)) + 1) & 0xFFFFFFFF)
+
+	var output []byte
+	for i := 0; i < len(data); i++ {
+		tmp := (data[i] ^ byte((curKey>>13)&0xFF))
+		output = append(output, tmp^_bin8Key[i&7])
+		curKey = uint32(((54323 * uint(curKey)) + 1) & 0xFFFFFFFF)
+	}
+
+	return output
+}