refactor: replace djb2 with xored hash func

pkg/hashing/xorhash.go

@@ -0,0 +1,19 @@
+package hashing
+
+// XORHash applies XOR to the given bytearray and then hashes it.
+func XORHash(s []byte) uint64 {
+	k := []byte{'h', 'a', 'd', 'e', 's'} // randomize?
+	for i := 0; i < len(s); i++ {
+		s[i] ^= k[i%len(k)]
+	}
+	return djb2(s)
+}
+
+// simple djb2 hashing algorithm implementation.
+func djb2(s []byte) uint64 {
+	var hash uint64 = 5381
+	for _, c := range s {
+		hash = ((hash << 5) + hash) + uint64(c)
+	}
+	return hash
+}